Draft Revision to CAR Section 9 Series M Part I ISSUE II -Meteorological Service for Air Navigation

GOVERNMENT OF INDIA OFFICE OF THE DIRECTOR GENERAL OF CIVIL AVIATION TECHNICAL CENTRE, OPP SAFDURJUNG AIRPORT, NEW DELHI CIVIL AVIATION REQUIREMENTS SECTION 9 – AIR SPACE AND AIR TRAFFIC MANAGEMENT SERIES M PART I, ISSUE II, 24th March, 2017 EFFECTIVE: FORTHWITH F. NO. AV.27077/1/2010-ANS Subject: Meteorological Service for Air Navigation 1. INTRODUCTION In pursuant to Article 28 of the Convention on International Civil Aviation each contracting State undertakes to provide Air navigation facilities and standard systems in accordance with standards which may be recommended or established from time to time, pursuant to this Convention. International Civil Aviation Organization adopts and amends from time to time, as may be necessary, international standards and recommended practices and procedures for Meteorological services for International Air Navigation in Annex 3. This CAR is issued under the provisions of Rule 29C and Rule 133A of the Aircraft Rules, 1937 for provision of Meteorological services for International Air Navigation to ensure the flow of information/data necessary for the safety, regularity and efficiency of international air navigation. 1.1 Definitions When the following terms are used in the Standards and Recommended Practices for Meteorological Service for International Air Navigation, they have the following meanings: Aerodrome - A defined area on land or water (including any buildings, installations and equipment) intended to be used either wholly or in part for the arrival, departure and surface movement of aircraft. Aerodrome Climatological summary- Concise summary of specified meteorological elements at an aerodrome, based on statistical data. Aerodrome climatological table - Table providing statistical data on the observed occurrence of one or more meteorological elements at an aerodrome. Rev. 4, ___October 2024 1CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Aerodrome control tower - A unit established to provide air traffic control service to aerodrome traffic. Aerodrome elevation - The elevation of the highest point of the landing area. Aerodrome meteorological office - An office designated to provide meteorological service for aerodromes serving international air navigation. Aerodrome reference point - The designated geographical location of an aerodrome Aeronautical fixed service (AFS) - A telecommunication service between specified fixed points provided primarily for the safety of air navigation and for the regular, efficientand economicaloperationof airservices. Aeronautical fixed telecommunication network (AFTN) - A worldwide system of aeronautical fixed circuits provided, as part of the aeronautical fixed service, for the exchange of messages and/or digital data between aeronautical fixed stations having the same or compatible communications characteristics. Aeronautical meteorological station – A station designated to make observations and meteorological reports for use in international airnavigation. Aeronautical mobile service (RR S1.32) - A mobile service between aeronautical stations and aircraft stations, or between aircraft stations, in which survival craft stations may participate; emergency position-indicating radio beacon stations may also participate in this service on designated distress and emergency frequencies. Aeronautical telecommunication station - A station in the aeronautical telecommunication service. Aircraft - Any machine that can derive support in the atmosphere from the reactions of the air other than the reactions of the air against the earth’s surface. Aircraft observation - The evaluation of one or more meteorological elements made from an aircraft in flight. AIRMET information - Information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather phenomena which may affect the safety of low-level aircraft operations and which was not already included in the forecast issued for low-level flights in the flight information region concerned or sub-area thereof. Air-report- - A report from an aircraft in flight prepared in conformity with requirements for position, and operational and/ or meteorological reporting. Note.— Details of the AIREP form are given in the PANS-ATM (Doc 4444). Air traffic services unit - A generic term meaning variously, air traffic control unit, flight information Centre or air traffic services reporting office. Alternate aerodrome - An aerodrome to which an aircraft may proceed when it becomes either impossible or inadvisable to proceed to or to land at the aerodrome of intended landing where the necessary services and facilities are available, where aircraft performance requirements can be met and which is operational at the 2 Rev. _--Rev 4 , ---October 2024CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Expected time of use. Alternate aerodromes include the following: Take-off alternate - An alternate aerodrome at which an aircraft would be able to land should this become necessary shortly after take-off and it is not possible to use the aerodrome of departure. En-route alternate - An alternate aerodrome at which an aircraft would be able to land in the event that a diversion becomes necessary while en route. Destination alternate - An alternate aerodrome at which an aircraft would be able to land should it become impossible or inadvisable to land at the aerodrome of intended landing. Note.— The aerodrome from which a flight departs may also be an en-route or a destination alternate aerodrome for that flight. Altitude - The vertical distance of a level, a point or an object considered as a point, measured from mean sealevel(MSL) Approach control unit - A unit established to provide air traffic control service to controlled flights arriving at, or departing from, one or more aerodromes. Appropriate ATS authority - The relevant authority designated by the State responsible for providing air traffic services in the airspace concerned. Area control centre (ACC) - A unit established to provide air traffic control service to controlled flights in control areas under its jurisdiction. Area navigation (RNAV) - A method of navigation which permits aircraft operations on any desired flight path within the coverage of ground- or space-based navigation aids or within the limits of the capability of self-contained aids, or a combination of these. Note. — Area navigation includes performance-based navigation as well as otheroperations that do not meet the definition of performance-based navigation. Automatic dependent surveillance — contract (ADS-C) - A means by which the terms of an ADS-C agreement will be exchanged between the ground system and the aircraft, via a data link, specifying under what conditions ADS-C reports would be initiated, and what data would be contained in the reports. Note. — The abbreviated term “ADS contract” is commonly used to refer to ADS event contract, ADS demand contract, ADS periodic contract or an emergency mode. Briefing - Oral commentary on existing and/or expected meteorological conditions. Cloud of operational significance - A cloud with the height of cloud base below 1 500 m (5 000 ft) or below the highest minimum sector altitude, whichever is greater or a cumulonimbus cloud or a towering cumulus cloud at any height. Consultation - Discussion with a meteorologist or another qualified person of existing and/or expected meteorological conditions relating to flight operations; a discussion includes answers to questions. Control area (CTA) - A controlled airspace extending upwards from as pacified limit above the earth. Rev. _--Rev 4 , ---October 2024 3CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Cruising level - A level maintained during a significant portion of a flight. Elevation - The vertical distance of a point or a level, on or affixed to the surface of the earth, measured from meansea level. Extended range operation - Any flight by an aero plane with two turbine power- units where the flight time at the one power-unit inoperative cruise speed (in ISA and still air conditions), from a point on the route to an adequate alternate aerodrome, is greater than the threshold time approved by the State of the Operator. Flight crew member - A licensed crew member charged with duties essential to the operation of an aircraft during a flight duty period. Flight documentation - Written or printed documents, including charts or forms, containing meteorological information for a flight. Flight information Centre (FIC) - A unit established to provide flight information service and alerting service. Flight information region (FIR) - An airspace of defined dimensions within which flight information service and alerting service are provided. Flight level. A surface of constant atmospheric pressure which is related to a specific pressure datum, 1 013.2 hecto Pascal’s (hPa), and is separated from other such surfaces by specific pressure intervals. Note 1. — A pressure type altimeter calibrated in accordance with the Standard Atmosphere: a) When set to a QNH altimeter setting, will indicate altitude; b) when set to a QFE altimeter setting, will indicate height above the QFE reference datum; and c) When set to a pressure of 1 013.2 hPa, may be used to indicate flight levels. Note 2. — The terms “height” and “altitude”, used in Note 1, indicate altimetry ratherthan geometric height sand altitudes. Forecast - A statement of expected meteorological conditions for a specified time or period, and for a specified area or portion of airspace. GAMET area forecast – An area forecast in abbreviated plain language for low-level flights for a flight information region or sub-area thereof, prepared by the meteorological office designated by the meteorological authority concerned and exchanged with meteorological offices in adjacent flight information regions, as agreed between the meteorological authorities concerned. Grid point data in digital form - Computer processed meteorological data for a set of regularly spaced points on a chart, for transmission from a meteorological computer to another computer in a code form suitable for automated use. Note.— In most cases such data are transmitted on medium or high speed telecommunications channels. Height - The vertical distance of a level, a point or an object considered as a point, measured from as pacified datum. Rev. _--Rev 4 , ---October 2024 4CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Human Factors principles - Principles which apply to aeronautical design, certification, training, operations and maintenance and which seek safe interfac e between the human and other system components by proper consideration to human performance. International airways volcano watch (IAVW) - International arrangements for monitoring and providing warnings to aircraft of volcanic ash in the atmosphere. Note. — The IAVW is based on the cooperation of aviation and non-aviation operational units using information derived from observing sources and networks that are provided by States. The watch is coordinated by ICAO with the cooperation of other concerned international organizations. ICAO meteorological information exchange model (IWXXM). A data model for representing aeronautical meteorological information. Level - A generic term relating to vertical position of an aircraft in flight and meaning variously height, altitude or flight level. Meteorological authority - The authority providing or arranging for the provision of meteorological service for international air navigation on behalf of a Contracting State. Meteorological bulletin-A text comprising meteorological information preceded by an appropriate heading. Meteorological information - Meteorological report, analysis, forecast, and any other statement relating to existing or expected meteorological conditions. Meteorological office. An office designated to provide meteorological service for international airnavigation. Meteorological report - A statement of observed meteorological conditions related to a specified time and location. Meteorological satellite - An artificial Earth satellite making meteorological observations and transmitting these observations to Earth. Meteorological watch office (MWO) - An office designated to provide information concerning the occurrence or expected occurrence of specified en-route weather and other phenomena in the atmosphere that may affect the safety of aircraft operations within its specified area of responsibility. Minimum sector altitude - The lowest altitude which may be used which will provide a minimum clearance of 300 m (1 000 ft) above all objects located in the area contained within a sector of a circle of 46 km (25 NM) radius centered on a radio aid to navigation. Navigation specification - A set of aircraft and flight crew requirements needed to support performance-based navigation operations within a defined airspace. There are two kinds of navigation specifications: Required navigation performance (RNP) specification. A navigation specification based on area navigation that includes the requirement for performance monitoring and alerting, designated by the prefix RNP, e.g. RNP 4, RNP APCH. Rev. _--Rev 4 , ---October 2024 5CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Area navigation (RNAV) specification. A navigation specification based on area navigation that does not include the requirement for performance monitoring and alerting, designated by the prefix RNAV, e.g. RNAV 5, RNAV 1. Note. — The Performance-based Navigation (PBN) Manual (Doc 9613), Volume II, contains detailed guidance on navigation specifications. Observation (meteorological) -The evaluation of one or more meteorological elements. Operational control - The exercise of authority over the initiation, continuation, diversion or termination of a flight in the interest of the safety of the aircraft and the regularity and efficiency of the flight. Operational flight plan - The operator’s plan for the safe conduct of the flight based on considerations of aero plane performance, other operating limitations and relevant expected conditions on the route to be followed and at the aerodromes concerned. Operational planning - The planning of flight operations by an operator. Operator - A person, organization or enterprise engaged in or offering to engage in an aircraft operation. Performance-based navigation (PBN) - Area navigation based on performance requirements for aircraft operating along an ATS route, on an instrument approach procedure orin a designated airspace. Note. — Performance requirements are expressed in navigation specification (RNAV specification, RNP specification) in terms of accuracy, integrity, continuity, availability and functionality needed for the proposed operation in the context of a particular air space concept. Pilot-in-command - The pilot designated by the operator, or in the case of general aviation, the owner, as being in command and charged with the safe conduct of a flight. Prevailing visibility - The greatest visibility value, observed in accordance with the definition of “visibility”, which is reached within at least half the horizon circle or within at least half of the surface of the aerodrome. These areas could comprise contiguous or non-contiguous sectors. Note. — This value may be assessed by human observation and/or instrumented systems. When instruments are installed, they are used to obtain the best estimate of the prevailing visibility. Prognostic chart - A forecast of a specified meteorological element(s) for a specified time or period and a specified surface or portion of airspace, depicted graphically on a chart. Quality assurance - All the planned and systematic activities implemented within the quality system, and demonstrated as needed, to provide adequate confidence that an entity will fulfil requirements for quality (ISO 9000*). Rev. _--Rev 4 , ---October 2024 6CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Quality control - The operational techniques and activities that are used to fulfil requirements for quality (ISO 9000*). Quality management - All activities of the overall management function that determine the quality policy, objectives and responsibilities, and implementing them by means such as quality planning, quality control, quality assurance and quality improvement withinthe qualitysystem(ISO 9000*). * ISO Standard 9000 — Quality Management Systems — Fundamentals and Vocabulary. Regional air navigation agreement - Agreement approved by the Council of ICAO Normally on the advice of a regional air navigation meeting. Reporting point. A specified geographical location in relation to which the position of an aircraft can be reported. Rescue coordination Centre - A unit responsible for promoting efficient organization of search and rescue services and for coordinating the conduct of search and rescue operations within a search and rescue region. Runway - A defined rectangular area on a land aerodrome prepared for the landing and take- off of aircraft. Runway visual range (RVR) - The range over which the pilot of an aircraft on the Centre line of a runway can see the runway surface markings or the lights delineating the runway or identifying its Centre line. Search and rescue services unit - A generic term meaning, as the case may be, rescue coordination centre, rescue sub-centre or alerting post. SIGMET information - Information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather and other phenomena in the atmosphere that may affect the safety of aircraft operations. Space weather centre (SWXC). A centre designated to monitor and provide advisory information on space weather phenomena expected to affect high-frequency radio communications, communications via satellite, GNSS-based navigation and surveillance systems and/or pose a radiation risk to aircraft occupants. Note. – A space weather centre is designated as global and/or regional. Standard isobaric surface - An isobaric surface used on a worldwide basis for representing and analyzing the conditions in the atmosphere. State volcano observatory - A volcano observatory, designated by regional air navigation agreement, to monitor active or potentially active volcanoes within a State and to provide information on volcanic activity to its associated area control Centre/flight information Centre, meteorological watch office and volcanic ash advisory Centre. Threshold - The beginning of that portion of the runway usable for landing. Touchdown zone - The portion of a runway, beyond the threshold, where it is intended landing aero planes first contact the runway. Rev. _--Rev 4 , ---October 2024 7CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Tropical cyclone - Generic term fora non-frontal synoptic scale cyclone originating over tropical or sub-tropical waters with organized convection and definite cyclonic surface wind circulation. Tropical cyclone advisory Centre (TCAC) – A meteorological Centre designated by regional air navigation agreement to provide advisory information to meteorological watch offices, world area forecast centers and international OPMET data banks regarding the position, forecast direction and speed of movement, central pressure and maximum surface windof tropicalcyclones. Upper-air chart - A meteorological chart relating to a specified upper-air surface or layer of the atmosphere. Visibility - Visibility for aeronautical purposes is the greater of: a) the greatest distance at which a black object of suitable dimensions, situated near the ground, can be seen and recognized when observed against a bright background; b) The greatest distance at which lights in the vicinity of 1 000 candelas can be seen and identified against an unlit background. Note. — the two distances have different values in air of a given extinction coefficient, and the latter b) varies with the background illumination. The former a) is represented by the meteorological optical range (MOR). Volcanic ash advisory Centre (VAAC) - A meteorological Centre designated by regional air navigation agreement to provide advisory information to meteorological watch offices, area control centers, flight information centers, world area forecast centers and international OPMET data banks regarding the lateral and vertical extent and forecast movement of volcanic ash in the atmosphere. VOLMET - Meteorological information for aircraft in flight. Data link-VOLMET (D-VOLMET) - Provision of current aerodrome routine meteorological reports (METAR) and aerodrome special meteorological reports (SPECI), aerodrome forecasts (TAF), SIGMET, special air-reports not covered by a SIGMET and, where available, AIRMET via datalink. VOLMET broadcast - Provision, as appropriate, of current METAR, SPECI, TAF and SIGMET by means of continuous and repetitive voice broadcasts. World area forecast Centre (WAFC) - A meteorological Centre designated to prepare and issue significant weather forecasts and upper-air forecasts in digital form on a global basis direct to States using the aeronautical fixed service Internet- based services. World area forecast system (WAFS) - A worldwide system by which world area forecast centers provide aeronautical meteorological en-route forecasts in uniform standardized formats. Rev. _--Rev 4 , ---October 2024 8CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 1.2 Terms used with a limited meaning For the purpose of this CAR, the following terms are used with a limited meaning as indicated below: a) to avoid confusion in respect of the term “service” between the meteorological service considered as an administrative entity and the service which is provided, “meteorological authority” is used for the former and“ service” for the latter; b) “provide” is used solely in connection with the provision of service; c) “issue” is used solely in connection with cases where the obligation specifically extends to sending out the information to a user; d) “make available” is used solely in connection with cases where the obligation ends with making the information accessible to a user; and e) “Supply” is used solely in connection with cases where either c) or d) applies. 2. General Provisions 2.1 Objective, determination and provision of meteorological service 2.1.1 The objective of meteorological service shall be to contribute towards the safety, regularity and efficiency of international air navigation. 2.1.2 The objective shall be achieved by supplying the following users: operators, flight crew members, air traffic services units, search and rescue services units, airport managements and others concerned with the conduct or development of international air navigation, with the meteorological information necessary for the performance of their respective functions. 2.1.3 The meteorological services to be provided for international air navigation over Indian Territory shall be in accordance with the provisions contained in this CAR. Meteorological service to be provided for international air navigation over international waters and other areas outside the territory of India shall be in accordance with regional air navigation agreements. 2.1.4 India Meteorological Department (IMD) shall provide Meteorological Services for safety, regularity, and efficiency of International air navigation in accordance with the provisions of this CAR and regional air navigation agreements in this regard. Note1. — Detailed specifications concerning presentation and contents of the aeronautical information publication is provided in PANS-AIM (Doc 10066), Appendix 2. Note2. — IMD shall be the designated Meteorological Authority for provision of Meteorological Services for air navigation over the Indian Territory; including international waters and other areas outside the territory of India in accordance with regional air navigation agreement. 2.1.5 IMD shall ensure compliance with the requirements of the World 9 Rev. _--Rev 4 , ---October 2024CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Meteorological Organization (WMO) in respect of qualifications, competencies, education and training of meteorological personnel providing service for international air navigation. Note.— Requirements concerning qualifications, competencies, education and training of meteorological personnel in aeronautical meteorology are given in WMO Publication No. 49, Technical Regulations, Volume I — General Meteorological Standards and Recommended Practices, Part V — Qualifications and Competencies of Personnel Involved in the Provision of Meteorological (Weather and Climate) and Hydrological Services, Part VI — Education and Training of Meteorological Personnel, and Appendix A — Basic Instruction Packages. 2.2 Supply, use, quality management and interpretation of meteorological information 2.2.1 Close liaison shall be maintained between those concerned with the supply and those concerned with the use of meteorological information on matters which affect the provision of meteorological service for international air navigation. 2.2.2 IMD shall ensure establishment and implementation of a properly organized quality system comprising procedures, processes and resources necessary to provide for the quality management of the meteorological information to be supplied to the users listed in 2.1.2. 2.2.3 The quality system established in accordance with 2.2.2 should be in conformity with the International Organization for Standardization (ISO) 9000 series of quality assurance standards and should be certified by an approved organization. Note.— Note.— The ISO 9000 series of quality assurance standards provide a basic framework for the development of a quality assurance programme. The details of a successful programme are to be formulated by each State and in most cases are unique to the State organization Guidance on the establishment and implementation of quality management system is given in the Guide to the Implementation of Quality Management Systems for National Meteorological and Hydrological Services and Other Relevant Service Providers (WMO-No. 1100). 2.2.4 The quality system should provide the users with assurance that the meteorological information supplied complies with the stated requirements in terms of the geographical and spatial coverage, format and content, time and frequency of issuance and period of validity, as well as the accuracy of measurements, observations and forecasts. When the quality system indicates that meteorological information to be supplied to the users does not comply with the stated requirements, and automatic error correction procedures are not appropriate, such information should not be supplied to the users unless it is validated with the originator. Note. — Requirements concerning the geographical and spatial coverage, format and content, time and frequency of issuance and period of validity of meteorological information to be supplied to aeronautical users are given in para 3, 4, 6, 7, 8, 9 and 10 and Appendices 2, 3, 5, 6, 7, 8 and 9 of this CAR and the relevant regional air navigation plans. Guidance concerning the accuracy of measurement and observation, and accuracy of forecasts is given 10 Rev. _--Rev 4 , ---October 2024CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 in Attachments A and B respectively, to this CAR. 2.2.5 In regard to the exchange of meteorological information for operational purposes, the quality system should include verification and validation procedures and resources for monitoring adherence to the prescribed transmission schedules for individual messages and/or bulletins required to be exchanged, and the times of their filing for transmission. The quality system should be capable of detecting excessive transit times of messages and bulletins received. Note. — Requirements concerning the exchange of operational meteorological information are given in para 11 and Appendix 10 of this CAR. 2.2.6 Demonstration of compliance of the quality system applied shall be by audit. If non- conformity of the system is identified, action shall be initiated to determine and correct the cause. All audit observations shall be evidence- based and properly documented. 2.2.7 Owing to the variability of meteorological elements in space and time, to limitations of observing techniques and to limitations caused by the definitions of some of the elements, the specific value of any of the elements given in a report shall be understood by the recipient to be the best approximation of the actual conditions at the time of observation. Note. — Guidance on the operationally desirable accuracy of measurement or observation is given in Attachment A of this CAR. 2.2.8 Owing to the variability of meteorological elements in space and time, to limitations of forecasting techniques and to limitations caused by the definitions of some of the elements, the specific value of any of the elements given in a forecast shall be understood by the recipient to be the most probable value which the element is likely to assume during the period of the forecast. Similarly, when the time of occurrence or change of an element is given in a forecast, this time shall be understood to be the most probable time. Note. — Guidance on the operationally desirable accuracy of forecasts is given in Attachment B of this CAR. 2.2.9 The meteorological information supplied to the users listed in 2.1.2 shall be consistent with Human Factors principles and shall be in forms which require a minimum of interpretation by these users, as specified in the following Paras. Note. — Guidance material on the application of Human Factors principles canbe found in the Human Factors Training Manual (Doc 9683). 2.2.10 Recommendation.—Contracting States should ensure that the meteorological information supplied to the users listed in 2.1.2 is provided through information services. Note 1.—In the context of system-wide information management (SWIM), the notion of information service addresses machine interaction in a service-oriented architecture. Note2.- Procedures on information services are contained in the Procedures for Air Navigation Services – Information (PANS-IM, DOC 10199). Rev. _--Rev 4 , ---October 2024 11CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Note3.- Guidance material on information services can be found in the Manual on System-wide Information Implementation (Doc 10203). 2.3 Notifications required from operators 2.3.1 An operator requiring meteorological service or changes in existing meteorological service shall notify IMD or concerned aerodrome meteorological office, sufficiently in advance. The minimum amount of advance notice required shall be as agreed between the IMD and the Rev. _--Rev 4 , ---October 2024 12CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Operator concerned. 2.3.2 IMD shall be notified by the operator requiring service when: a) new routes or new types of operations are planned; b) changes of a lasting character are to be made in scheduled operations; and c) Other changes, affecting the provision of meteorological service, are planned. Such information shall contain all details necessary for the planning of appropriate arrangements by IMD. 2.3.3 The operator or a flight crew member shall ensure that, where required by the meteorological authority in consultation with users, the aerodrome meteorological office concerned is notified: a) of flight schedules; b) when non-scheduled flights are to be operated; and c) When flights are delayed, advanced or cancelled. 2.3.4 The notification to the aerodrome meteorological office, of individual flights should contain the following information except that, in the case of scheduled flights, the requirement for some or all of this information may be waived as agreed between the aerodrome meteorological office and the operator concerned: a) aerodrome of departure and estimated time of departure; b) destination and estimated time of arrival; c) route to be flown and estimated times of arrival at, and departure from, any intermediate aerodrome (s); d) alternate aerodromes needed to complete the operational flight plan and taken from the relevant list contained in the regional air navigation plan; e) cruising level; f) type of flight, whether under visual or instrument flight rules; g) type of meteorological information requested for a flight crew member, whether flight documentation and/or briefing or consultation; and h) Time at which briefing, consultation and/or flight documentation are required. 3. GLOBAL SYSTEMS, SUPPORTING CENTRE AND METEOROLOGICAL OFFICES Note. – Please refer Appendix 2 of this CAR for technical specifications and other detailed criteria. 3.1 Objective of the world area forecast system (WAFS) The technical specifications related to World Area Forecast System (WAFS) are Rev. _--Rev 4 , ---October 2024 13CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Stipulates in Chapter 3 and Appendix 2 of ICAO Annex 3 for the contracting states which have accepted responsibilities for providing a World Area Forecast Centers (WAFC). India is not a WAFC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with them and use its products/services effectively. 3.2 World area forecast centers (WAFC) The technical specifications related to World Area Forecast System (WAFS) are stipulates in Chapter 3 and Appendix 2 of ICAO Annex 3 for the contracting states which have accepted responsibilities for providing a World Area Forecast Centers (WAFC). India is not a WAFC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with them and use its products/services effectively. 3.2.1 Intentionally left blank. 3.2.2 Intentionally left blank. 3.3 Aerodrome meteorological offices 3.3.1 IMD shall establish one or more aerodrome and/or other meteorological offices which shall be adequate for the provision of the meteorological service required to satisfy the needs of international air navigation. 3.3.2 An aerodrome meteorological office shall carry out all or some of the following functions as necessary to meet the needs of flight operations at the aerodrome: a) prepare and/or obtain forecasts and other relevant information for flights with which it is concerned; the extent of its responsibilities to prepare forecasts shall be related to the local availability and use of en- route and aerodrome forecast material received from other offices; b) Prepare and/or obtain forecasts of local meteorological conditions; c) Maintain a continuous survey of meteorological conditions over the aerodromes for which it is designated to prepare forecasts; d) Provide briefing, consultation and flight documentation to flight crew members and/or other flight operations personnel; e) Supply other meteorological information to aeronautical users; f) Display the available meteorological information; g) Exchange meteorological information with other aerodrome meteorological offices; and h) Supply information received on pre-eruption volcanic activity, a volcanic eruption or volcanic ash cloud, to its associated air traffic services unit, Rev. _--Rev 4 , ---October 2024 14CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Aeronautical information service unit and meteorological watch office as agreed between the meteorological, aeronautical information service and ATS authorities concerned. 3.3.3 The aerodromes for which landing forecasts are required shall be determined by regional air navigation agreement. 3.3.4 For an aerodrome without an aerodrome meteorological office located at the aerodrome: a) The meteorological authority concerned shall designate one or more aerodrome meteorological office(s) to supply meteorological information as required; and b) The competent authorities shall establish means by which such information can be supplied to the aerodromes concerned. 3.4 Meteorological watch offices (MWO) 3.4.1 IMD shall establish one or more meteorological watch offices (MWO) for provision of services enumerated under para 3.4.2 to cover all the Flight Information Regions of India. Note.— Guidance on the bilateral or multilateral arrangements between Contracting States for the provision of meteorological watch office services, including for cooperation and delegation, can be found provision in the Manual of Aeronautical Meteorological Practice (Doc 8896). 3.4.2 A MWO shall: a) maintain watch over meteorological conditions affecting flight operations within its area of responsibility; b) prepare SIGMET and other information relating to its area of responsibility; c) supply SIGMET information and, as required, other meteorological information to associated air traffic services units; d) disseminate SIGMET information; e) when required by regional air navigation agreement, in accordance with 7.2.1 1) prepare AIRMET information related to its area of responsibility; 2) supply AIRMET information to associated air traffic services units; and 3) disseminate AIRMET information; f) supply information received on pre-eruption volcanic activity, a volcanic eruption and volcanic ash cloud for which a SIGMET has not already been issued, to its associated ACC/FIC, as agreed between the meteorological and ATS authorities concerned, and to its associated VAAC as Rev. _--Rev 4 , ---October 2024 15CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Determined by regional air navigation agreement; and g) Supply information received concerning the release of radioactive materials into the atmosphere, in the area for which it maintains watch or adjacent areas, to its associated ACC/FIC, as agreed between the meteorological and ATS authorities concerned, and to aeronautical information service units, as agreed between the meteorological and appropriate civil aviation authorities concerned. The information shall comprise location, date and time of the release, and forecast trajectories of the radioactive materials. Note. — The information is provided by WMO regional specialized meteorological centers (RSMC) for the provision of transport model products for radiological environmental emergency response, at the request of the delegated authority of the State in which the radioactive material was released into the atmosphere, or the International Atomic Energy Agency (IAEA). The information is sent by the RSMC to a single contact point of the national meteorological service in each State. This contact point has the responsibility of redistributing the RSMC products within the State concerned. Furthermore, the information is provided by IAEA to RSMC co-located with VAAC London (designated as the focal point) which in turn notifies theACCs/FICs concerned about the release. 3.4.3 The boundaries of the area over which meteorological watch is to be maintained by a MWO shall, be coincident with the boundaries of a FIR or a CTA or a combination of FIRs and/or CTAs. 3.5 Volcanic ash advisory centers (VAAC) The technical specifications related to Volcanic Ash Advisory Centers (VAACs) are stipulates in Chapter 3 and Appendix 2 of ICAO Annex 3 for the contracting states which have accepted responsibilities for providing a VAAC. India is not a VAAC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with VAAC and use its products/services effectively. 3.6 State volcano observatories Intentionally left blank. 3.7 Tropical cyclone advisory centers IMD shall establish Tropical Cyclone Advisory Centers (TCAC) having adequate facilities to: a) monitor the development of tropical cyclones in its area of responsibility, using geostationary and polar-orbiting satellite data, radar data and other meteorological information; b) issue advisory information concerning the position of the cyclone Centre, change in intensity at time of observation its direction and speed of 16 Rev. _--Rev 4 , ---October 2024CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 movement, central pressure and maximum Rev. _--Rev 4 , ---October 2024 17CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Surface wind near the Centre; in abbreviated plain language to: 1) MWOs in its area of responsibility; 2) other TCACs whose areas of responsibility may be affected; and 3) WAFCs, international OPMET data banks, and centers designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services; and c) Issue updated advisory information to MWOs for each tropical cyclone, as necessary, but at least every six hours. 3.8 Space weather centers (SWXC) The technical specifications related to SWXC are stipulates in Chapter 3, Appendix 2 and Attachment E of ICAO Annex 3 for the contracting states which have accepted responsibilities to monitor and provide advisory information on space weather. India is not a SWXC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with SWXC and use its products/services effectively. 3.8.1 Intentionally left blank. 3.8.2 Intentionally left blank. 3.8.3 Intentionally left blank. 4. METEOROLOGICAL OBSERVATIONS AND REPORTS Note. — Please refer Appendix 3 of this CAR for technical specifications and detailed criteria . 4.1 Aeronautical meteorological stations and observations 4.1.1 IMD shall establish at aerodromes and other points of significance to international air navigation, such aeronautical meteorological stations as it determines to be necessary. An aeronautical meteorological station may be a separate station or may be combined with a synoptic station. Note. — Aeronautical meteorological stations may include sensors installed outside the aerodrome, where considered justified, by the meteorological authority to ensure the compliance of meteorological service for international air navigation with the provisions of this CAR. 4.1.2 IMD should establish, or arrange for the establishment of, aeronautical meteorological stations on offshore structures or at other points of significance if requested by the operators of the concerned offshore structure in support of helicopter operations to offshore structures. Rev. _--Rev 4 , ---October 2024 18CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 4.1.3 Aeronautical meteorological stations shall make routine observations at fixed intervals. At aerodromes, the routine observations shall be supplemented by special observations whenever specified changes occur in respect of surface wind, visibility, runway visual range, present weather, clouds and/or air temperature. 4.1.4 IMD shall establish a mechanism for its aeronautical meteorological stations to be inspected at sufficiently frequent intervals to ensure that a high standard of observations is maintained, that instruments and all their indicators are functioning correctly, and to check whether the exposure of the instruments has changed significantly. Note. — Guidance on the inspection of aeronautical meteorological stations including the frequency of inspections is given in the Manual on Automatic Meteorological Observing Systems at Aerodromes (Doc 9837). 4.1.5 At aerodromes, with runways intended for Category II and III instrument approach and landing operations, automated equipment for measuring or assessing, as appropriate, and for monitoring and remote indicating of surface wind, visibility, runway visual range, height of cloud base, air and dew-point temperatures and atmospheric pressure shall be installed to support approach and landing and take-off operations. These devices shall be integrated automatic systems for acquisition, processing, dissemination and display in real time of the meteorological parameters affecting landing and take-off operations. The design of integrated automatic systems shall observe Human Factors principles and include back-up procedures. Note 1. — Categories of precision approach and landing operations are defined in CAR Section 8 series B part 1. Note 2. — Guidance material on the application of Human Factors principles can be found in the ICAO Human Factors Training Manual (ICAO Doc 9683). 4.1.6 At aerodromes, with runways intended for Category I instrument approach and landing operations, automated equipment for measuring or assessing, as appropriate, and for monitoring and remote indicating of surface wind, visibility, runway visual range, height of cloud base, air and dew-point temperatures and atmospheric pressure should be installed to support approach and landing and take-off operations. These devices should be integrated automatic systems for acquisition, processing, dissemination and display in real time of the meteorological parameters affecting landing and take-off operations. The design of integrated automatic systems should observe Human Factors principles and include back-up procedures. 4.1.7 Where an integrated semi-automatic system is used for the dissemination/display of meteorological information, it should be capable of accepting the manual insertion of data covering those meteorological elements which cannot be observed by automatic means. 4.1.8 The observations shall form the basis for the preparation of reports to be disseminated at the aerodrome of origin and of reports to be disseminated beyond the aerodrome of origin. Rev. _--Rev 4 , ---October 2024 19CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 4.2 Agreement between meteorological authorities and air traffic services authorities An agreement between the IMD and the ATS authority should be established to cover, amongst other things: a) the provision in air traffic services units of displays related to integrated automatic systems; b) the calibration and maintenance of these displays/ instruments; c) the use to be made of these displays/instruments by air traffic services personnel; d) as and where necessary, supplementary visual observations (for example, of meteorological phenomena of operational significance in the climb-out and approach areas) if and when made by air traffic services personnel to update or supplement the information supplied by the meteorological station; e) meteorological information obtained from aircraft taking off or landing (for example, on wind shear); and f) if available, meteorological information obtained from ground weather radar. Note.—Guidance on the subject of coordination between ATS and aeronautical meteorological services is contained in the ICAO Manual on Coordination between Air Traffic Services, Aeronautical Information Services and Aeronautical Meteorological Services (ICAO Doc 9377). 4.3 Routine observations and reports 4.3.1 At aerodromes, routine observations shall be made throughout the 24 hours each day, unless otherwise agreed between IMD, the appropriate ATS authority, and the operator concerned. Such observations shall be made at intervals of one hour or, if so determined by regional air navigation agreement, at intervals of one half hour. At other aeronautical meteorological stations, such observations shall be made as determined by the IMD taking into account the requirements of air traffic services units and aircraft operations. 4.3.2 Reports of routine observations shall be issued as: a) local routine reports, only for dissemination at the aerodrome of origin, (intended for arriving and departing aircraft); and b) METAR for dissemination beyond the aerodrome of origin (mainly intended for flight planning, VOLMET broadcasts and D-VOLMET). Note.— Meteorological information used in ATIS (voice- ATIS and D-ATIS) is to be extracted from the local routine report, in accordance with CAR Section 9 Series E Part I Para 4.3.6.1g Rev. _--Rev 4 , ---October 2024 20CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 4.3.3 At aerodromes that are not operational throughout 24 hours in accordance with 4.3.1, METAR shall be issued prior to the aerodrome resuming operations in accordance with agreement between IMD, ATS authority and operator. 4.4 Special observations and reports 4.4.1 A list of criteria for special observations shall be established by the meteorological authority in consultation with the appropriate ATS authority, operators and others concerned. 4.4.2 Reports of special observations shall be issued as: a) local special reports, only for dissemination at the aerodrome of origin, (intended for arriving and departing aircraft); and b) SPECI for dissemination beyond the aerodrome of origin (mainly intended for flight planning, VOLMET broadcasts and D-VOLMET) unless METAR are issued at half-hourly intervals. Note.— Meteorological information used in ATIS (voice- ATIS and D-ATIS) is to be extracted from the local special report, in accordance with CAR Section 9 Series E Part I Para 4.3.6.1. 4.4.3 At aerodromes that are not operational throughout 24 hours in accordance with 4.3.1, following the resumption of the issuance of METAR, SPECI shall be issued, as necessary. 4.5 Contents of Reports 4.5.1 Local routine reports, local special reports, METAR and SPECI shall contain the following elements in the order indicated: a) identification of the type of report; b) location indicator; c) time of the observation; d) identification of an automated or missing report, when applicable; e) surface wind direction and speed; f) visibility; g) runway visual range, when applicable; h) present weather; i) cloud amount, cloud type (only for cumulonimbus and towering cumulus clouds) and height of cloud base or, where measured, vertical visibility; j) air temperature and dew-point temperature; and Rev. _--Rev 4 , ---October 2024 21CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 k) QNH and, when applicable, QFE (QFE included only in local routine and special reports). Note. — The location indicators referred to under b) and their significations are published in Location Indicators (Doc 7910). 4.5.2 In addition to elements listed under 4.5.1 a) to k), local routine reports, local special reports, METAR and SPECI should contain supplementary information to be placed after element k). 4.5.3 Optional elements included under supplementary information shall be included in METAR and SPECI in accordance with regional air navigation agreement. 4.6 Observing and reporting meteorological elements 4.6.1 Surface wind 4.6.1.1 The mean direction and the mean speed of the surface wind shall be measured, as well as significant variations of the wind direction and speed, and reported in degrees true and meter per second (or knots), respectively. 4.6.1.2 When local routine and special reports are used for departing aircraft, the surface wind observations for these reports should be representative of conditions along the runway; when local routine and special reports are used for arriving aircraft, the surface wind observations for these reports should be representative of the touchdown zone. 4.6.1.3 For METAR and SPECI, the surface wind observations should be representative of conditions above the whole runway where there is only one runway and the whole runway complex where there is more than one runway. 4.6.2 Visibility 4.6.2.1 The visibility as defined in this CAR shall be measured or observed, and reported in meters or kilometers. Note. — Guidance on the conversion of instrument readings into visibility is given in Attachment D of this CAR. 4.6.2.2 Intentionally left blank 4.6.2.3 For METAR and SPECI, the visibility observations should be representative of the aerodrome. 4.6.3 Runway visual range Note.— Guidance on the subject of runway visual range is contained in the ICAO Manual of Runway Visual Range Observing and Reporting Practices (Doc 9328). 4.6.3.1 Runway visual range as defined in this CAR shall be assessed on all runways intended for Category II and III instrument approach and landing operations. Rev. _--Rev 4 , ---October 2024 22CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 4.6.3.2 Runway visual range as defined in this CAR should be assessed on all runways intended for use during periods of reduced visibility, including: a) precision approach runways intended for Category I instrument approach and landing operations; and b) Runways used for take-off and having high-intensity edge lights and/orCentre line lights. Note.— Precision approach runways are defined in CAR Section 4 Series ‘B', Part 1, under “Instrument runway”. 4.6.3.3 The runway visual range, assessed in accordance with 4.6.3.1 and 4.6.3.2, shall be reported in meters throughout periods when either the visibility or the runway visual range is less than 1500 m. 4.6.3.4 Runway visual range assessments shall be representative of: a) the touchdown zone of the runway intended for non-precision or Category I instrument approach and landing operations; b) the touchdown zone and the mid-point of the runway intended for Category II instrument approach and landing operations; and c) The touchdown zone, the mid-point and stop-end of the runway intendedfor Category III instrument approach and landing operations. 4.6.3.5 The units providing air traffic service and aeronautical information service for an aerodrome shall be kept informed without delay of changes in the serviceability status of the automated equipment used for assessing runway visual range. 4.6.4 Present weather 4.6.4.1 The present weather occurring at the aerodrome shall be observed and reported as necessary. The following present weather phenomena shall be identified, as a minimum: rain, drizzle, snow and freezing precipitation (including intensity thereof), haze, mist, fog, freezing fog and thunderstorms (including thunderstorms in the vicinity). 4.6.4.2 For local routine and special reports, the present weather information shall be representative of conditions at the aerodrome. 4.6.4.3 For METAR and SPECI, the present weather information shall be representative of conditions at the aerodrome and, for certain specified present weather phenomena, in its vicinity. 4.6.5 Clouds 4.6.5.1 Cloud amount, cloud type and height of cloud base shall be observed, and reported as necessary to describe the clouds of operational significance. When the sky is obscured, vertical visibility shall be observed and reported, where measured, in lieu of cloud amount, cloud type and height of cloud Rev. _--Rev 4 , ---October 2024 23CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Base. The height of cloud base and vertical visibility shall be reported in meters (or feet). 4.6.5.2 Intentionally left blank. 4.6.5.3 Cloud observations for METAR and SPECI shall be representative of the aerodrome and its vicinity. 4.6.6 Air temperature and dew-point temperature 4.6.6.1 The air temperature and the dew-point temperature shall be measured and reported in degrees Celsius. 4.6.6.2 Observations of air temperature and dew-point temperature for local routine reports, local special reports, METAR and SPECI should be representative of the whole runway complex. 4.6.7 Atmospheric pressure The atmospheric pressure shall be measured, and QNH and QFE values shall be computed and reported in hector Pascals. 4.6.8 Supplementary information Observations made at aerodromes shall include the available supplementary information concerning significant meteorological conditions, particularly those in the approach and climb-out areas. Where practicable, the information should identify the location of the meteorological condition. 4.7 Reporting meteorological information from automatic observing systems Intentionally Left Blank. 4.7.1 Intentionally left blank. 4.7.2 Intentionally left blank. 4.7.3 Intentionally left blank. 4.8 Observations and reports of volcanic activity The occurrence of pre-eruption volcanic activity, volcanic eruptions and volcanic ash cloud should be reported without delay to the associated air traffic services unit, aeronautical information services unit and meteorological watch office. The report should be made in the form of a volcanic activity report comprising the following information in the order indicated: a) message type, VOLCANIC ACTIVITY REPORT; b) station identifier, location indicator or name of station; c) date/time of message; d) location of volcano and name if known; and e) concise description of event including, as appropriate, level of intensity of volcanic activity, occurrence of an eruption and its date and time, and the existence of a volcanic ash cloud in the area together with direction of ash cloud movement and height. Rev. _--Rev 4 , ---October 2024 24CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Note.— Pre-eruption volcanic activity in this context means unusual and/or increasing volcanic activity which could presage a volcanic eruption. 5. AIRCRAFT OBSERVATIONS AND REPORTS Note. — Technical specifications and detailed criteria related to this Para are given in Appendix 4 of this CAR. 5.1 Obligations of States Each Contracting State shall arrange, according to the provisions of this Para, for observations to be made by aircraft of its registry operating on international air routes and for the recording and reporting of these observations. 5.2 Types of aircraft observations The following aircraft observations shall be made: a) routine aircraft observations during en-route and climb-out phases of the flight; and b) Special and other non-routine aircraft observations during any phase of the flight. 5.3 Routine aircraft observations - designation 5.3.1 When air-ground data link is used and automatic dependent surveillance - contract (ADS-C) or secondary surveillance radar (SSR) Mode S is being applied, automated routine observations should be made every 15 minutes during the en-route phase and every 30 seconds during the climb-out phase for the first 10 minutes of the flight. 5.3.2 For helicopter operations to and from aerodromes on offshore structures, routine observations should be made from helicopters at points and times as agreed between the meteorological authorities and the helicopter operators concerned. 5.3.3 In the case of air routes with high-density air traffic (e.g. organized tracks), an aircraft from among the aircraft operating at each flight level shall be designated, at approximately hourly intervals, to make routine observations in accordance with 5.3.1. The designation procedures shall be in accordance with regional air navigation agreement. 5.3.4 In the case of the requirement to report during the climb-out phase, an aircraft shall be designated, at approximately hourly intervals, at each aerodrome to make routine observations in accordance with 5.3.1. 5.4 Routine aircraft observations - exemptions Aircraft not equipped with air-ground data link shall be exempted from making routine aircraft observations. Rev. _--Rev 4 , ---October 2024 25CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 5.5 Special aircraft observations Special observations shall be made by all aircraft whenever the following conditions are encountered or observed: a) moderate or severe turbulence; or b) moderate or severe icing; or c) severe mountain wave; or d) thunderstorms, without hail, that are obscured, embedded, widespread or in squall lines; or e) thunderstorms, with hail, that are obscured, embedded, widespread or in squall lines; or f) heavy dust storm or heavy sandstorm; or g) volcanic ash cloud; or h) Pre-eruption volcanic activity or a volcanic eruption. i) As of 5 4 November 2021, runway braking action encountered is not as good as reported. Note. — Pre-eruption volcanic activity in this context means unusual and/or increasing volcanic activity which could presage a volcanic eruption. 5.6 Other non-routine aircraft observations When other meteorological conditions not listed under 5.5, e.g. wind shear, are encountered and which, in the opinion of the pilot-in-command, may affect the safety or markedly affect the efficiency of other aircraft operations, the pilot-in- command shall advise the appropriate air traffic services unit as soon as practicable. Note.— Icing, turbulence and, to a large extent, wind shear are elements which, for the time being, cannot be satisfactorily observed from the ground and for which in most cases aircraft observations represent the only available evidence. 5.7 Reporting of aircraft observations during flight 5.7.1 Aircraft observations shall be reported by air-ground data link. Where air- ground data link is not available or appropriate, special and other non-routine aircraft observations during flight shall be reported by voice communications. 5.7.2 Aircraft observations shall be reported during flight at the time the observation is made or as soon thereafter as is practicable. 5.7.3 Aircraft observations shall be reported as air-reports. 5.8 Relay of air-reports by air traffic services units The meteorological authority concerned shall make arrangements with the appropriate ATS authority to ensure that, on receipt by the ATS units of: a) special air-reports by voice communications, the ATS units relay them without delay to their associated MWO; and b) Routine and special air-reports by data link communications, the ATS units relay them without delay to their associated MWO, the WAFCs and the centers designated by regional air navigation agreement for the operation Rev. _--Rev 4 , ---October 2024 26CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 of aeronautical fixed service Internet-based services. 5.9 Recording and post-flight reporting of aircraft observations of volcanic activity Special aircraft observations of pre-eruption volcanic activity, a volcanic eruption or volcanic ash cloud shall be recorded on the special air-report of volcanic activity form. A copy of the form shall be included with the flight documentation provided to flights operating on routes which, in the opinion of the meteorological authority concerned, could be affected by volcanic ash clouds. 6. FORECASTS Note.— Please refer Appendix 5 of this CAR for technical specifications and detailed criteria. 6.1 Use of forecasts The issue of a new forecast by an aerodrome meteorological office, such as a routine aerodrome forecast, shall be understood to cancel automaticallyany forecast of the same type previously issued for the same place and for the same period of validity or part thereof. 6.2 Aerodrome forecasts 6.2.1 An aerodrome forecast shall be prepared, in accordance with regional air navigation agreement, by the aerodrome meteorological office designated by the meteorological authority concerned. Note.— The aerodromes for which aerodrome forecasts are to be prepared and the period of validity of these forecasts are listed in the relevant facilities and services implementation document (FASID). 6.2.2 An aerodrome forecast shall be issued at a specified time not earlier than one hour prior to the beginning of its validity period and consist of a concise statement of the expected meteorological conditions at an aerodrome for a specified period. 6.2.3 Aerodrome forecasts and amendments thereto shall be issued as TAF and include the following information in the order indicated: a) identification of the type of forecast; b) location indicator; c) time of issue of forecast; d) identification of a missing forecast, when applicable; e) date and period of validity of forecast; f) identification of a cancelled forecast, when applicable; g) surface wind; h) visibility; i) weather; j) cloud; and Rev. _--Rev 4 , ---October 2024 27CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 k) expected significant changes to one or more of these elements during the Period of validity. Optional elements shall be included in TAF in accordance with regional air navigation agreement. 6.2.4 Aerodrome meteorological offices preparing TAF shall keep the forecasts under continuous review and, when necessary, shall issue amendments promptly. The length of the forecast messages and the number of changes indicated in the forecast shall be kept to a minimum. Note. — Guidance on methods to keep TAF under continuous review is given in Chapter 3 of the Manual of Aeronautical Meteorological Practice (ICAO Doc 8896). 6.2.5 TAF that cannot be kept under continuous review shall be cancelled. 6.2.6 The period of validity of a routine TAF should be not less than 9 hours nor more than 30 hours; the period of validity should be determined by regional air navigation agreement. Routine TAF valid for less than 12 hours should be issued every 3 hours and those valid for 12 to 30 hours should be issued every 6 hours. 6.2.7 When issuing TAF, aerodrome meteorological offices shall ensure that not more than one TAF is valid at an aerodrome at any given time. 6.3 Landing forecasts 6.3.1 A landing forecast shall be prepared by the aerodrome meteorological office designated by the meteorological authority concerned; as determined by regional air navigation agreement; such forecasts are intended to meet requirements of local users and of aircraft within about one hour’s flying time from the aerodrome. 6.3.2 Landing forecasts shall be prepared in the form of a trend forecast. 6.3.3 A trend forecast shall consist of a concise statement of the expected significant changes in the meteorological conditions at that aerodrome to be appended to a local routine report, a local special report, METAR or SPECI. The period of validity of a trend forecast shall be 2 hours from the time of the report which forms part of the landing forecast. 6.4 Forecasts for take-off 6.4.1 A forecast for take-off shall be prepared by the aerodrome meteorological office designated by the meteorological authority concerned as agreed between the meteorological authority and operators concerned. 6.4.2 A forecast for take-off shall refer to a specified period of time and should contain information on expected conditions over the runway complex in regard to surface wind direction and speed and any variations thereof, temperature, pressure (QNH), and any other elements as agreed locally. Rev. _--Rev 4 , ---October 2024 28CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 6.4.3 A forecast for take-off should be supplied to operators and flight crew Members on request within the 3 hours before the expected time of departure. 6.4.4 Aerodrome meteorological offices preparing forecasts for take-off should keep the forecasts under continuous review and, when necessary, should issue amendments promptly. 6.5 Area forecasts for low-level flights 6.5.1 When the density of traffic operating below flight level 100 (or up to flight level 150 in mountainous areas, or higher, where necessary) warrants the routine issue and dissemination of area forecasts for such operations, the frequency of issue, the form and the fixed time or period of validity of those forecasts and the criteria for amendments thereto shall be determined by the meteorological authority in consultation with the users. 6.5.2 Intentionally left blank. 6.5.3 Intentionally left blank. 7. SIGMET AND AIRMET INFORMATION, AERODROME WARNINGS AND WIND SHEAR WARNINGS AND ALERTS Note.— Please refer Appendix 6 of this CAR for technical specifications and detailed criteria. 7.1 SIGMET information 7.1.1 SIGMET information shall be issued by a meteorological watch office and shall give a concise description in abbreviated plain language concerning the occurrence and/or expected occurrence of specified en-route weather and other phenomena in the atmosphere that may affect the safety of aircraft operations, and of the development of those phenomena in time and space. 7.1.2 SIGMET information shall be cancelled when the phenomena are no longer occurring or are no longer expected to occur in the area. 7.1.3 The period of validity of a SIGMET message shall be not more than 4 hours. In the special case of SIGMET messages for volcanic ash cloud and tropical cyclones, the period of validity shall be extended up to 6 hours. 7.1.4 SIGMET messages concerning volcanic ash cloud and tropical cyclones should be based on advisory information provided by VAACs and TCACs, respectively, designated by regional air navigation agreement. 7.1.5 Close coordination shall be maintained between the meteorological watch office and the associated area control Centre/flight information Centre to ensure that information on volcanic ash included in SIGMET and NOTAM messages is consistent. 7.1.6 SIGMET messages shall be issued not more than 4 hours before the commencement of the period of validity. In the special case of SIGMET Rev. _--Rev 4 , ---October 2024 29CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 messages for volcanic ash cloud and tropical cyclones, these messages shall Be issued as soon as practicable but not more than 12 hours before the commencement of the period of validity. SIGMET messages for volcanic ash and tropical cyclones shall be updated at least every 6 hours. 7.2 AIRMET Information Intentionally left blank. 7.2.1 Intentionally left blank. 7.2.2 Intentionally left blank. 7.2.3 Intentionally left blank. 7.3 Aerodrome warnings 7.3.1 Aerodrome warnings shall be issued by the aerodrome meteorological office designated by the meteorological authority concerned and shall give concise information of meteorological conditions which could adversely affect aircraft on the ground, including parked aircraft, and the aerodrome facilities and services. 7.3.2 Aerodrome warnings shall be cancelled when the conditions are no longer occurring and/ or no longer expected to occur at the aerodrome. 7.4 Wind shear warnings and alerts Note.— Guidance on the subject is contained in the Manual on Low-level Wind Shear (Doc 9817). Wind shear alerts are expected to complement wind shear warnings and together are intended to enhance situational awareness of wind shear. 7.4.1 Wind shear warnings shall be prepared by the concerned aerodrome meteorological office and shall give concise information of the observed wind shear which could adversely affect aircraft on the approach path or take-off path or during circling approach. 7.4.2 Wind shear warnings for arriving aircraft and/or departing aircraft should be cancelled when aircraft reports indicate that wind shear no longer exists, or alternatively, after two hours elapsed time. The criteria for the cancellation of a wind shear warning should be defined locally for each aerodrome, asagreed between the meteorological authority, the appropriate ATS authority and the operators concerned. 7.4.3 At aerodromes where wind shear is detected by automated, ground-based, wind shear remote-sensing or detection equipment, wind shear alerts generated by these systems shall be issued. Wind shear alerts shall give concise, up-to-date information related to the observed existence of wind shear involving a headwind/tailwind change of 7.5 m/s (15 kt) or more which could adversely affect aircraft on the final approach path or initial take-offpath and aircraft on the runway during the landing roll or take-off run. Rev. _--Rev 4 , ---October 2024 30CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 7.4.4 Wind shear alerts issued in accordance with para 7.4.3 should be updated at Least every minute. The wind shear alert should be cancelled as soon as the headwind/tailwind change falls below 7.5 m/s (15 kt). 8. AERONAUTICAL CLIMATOLOGICAL INFORMATION Note1.— Please refer Appendix 7 of this CAR for technical specifications and detailed criteria. 8.1 General provisions 8.1.1 Aeronautical climatological information required for the planning of flight operations shall be prepared in the form of aerodrome climatological tables and aerodrome climatological summaries. Such information shall be supplied to aeronautical users as agreed between the meteorological authority and the users concerned. Note.— Climatological data required for aerodrome planning purposes are set out in CAR Section 4 Series B Part I para.3.1.4 & Attachment A. 8.1.2 Aeronautical climatological information shall normally be based on observations made over a period of at least five years and the period should be indicated in the information supplied. 8.1.3 Climatological data related to sites for new aerodromes and to additional runways at existing aerodromes should be collected starting as early as possible before the commissioning of those aerodromes or runways. 8.2 Aerodrome climatological tables IMD should make arrangements for collecting and retaining the necessary observational data and have the capability: a) to prepare aerodrome climatological tables for each regular and alternate international aerodrome within its territory; and b) to make available such climatological tables to an aeronautical user within a time period as agreed between the meteorological authority and that the user concerned. 8.3 Aerodrome climatological summaries Aerodrome climatological summaries should follow the procedures prescribed by the World Meteorological Organization (WMO). Where computer facilities are available to store, process and retrieve the information, the summaries should be published, or otherwise made available to aeronautical users on request. Where such computer facilities are not available, the summaries should be prepared using the models specified by the WMO, and should be published and kept up to date as necessary. 8.4 Copies of meteorological observational data Rev. _--Rev 4 , ---October 2024 31CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Each meteorological authority, on request and to the extent practicable, shall make available to any other meteorological authority, to operators and to others concerned with the application of meteorology to international air navigation, meteorological observational data required for research, investigation or operational analysis. 9. SERVICE FOR OPERATORS AND FLIGHT CREW MEMBERS Note.— Please refer Appendix 8 of this CAR for technical specifications and detailed criteria. 9.1 General provisions 9.1.1 Meteorological information shall be supplied to operators and flight crew members for: a) pre-flight planning by operators; b) in-flight re-planning by operators using centralized operational control of flight operations; c) use by flight crew members before departure; and d) Aircraft in flight. 9.1.2 Meteorological information supplied to operators and flight crew members shall cover the flight in respect of time, altitude and geographical extent. Accordingly, the information shall relate to appropriate fixed times, or periods of time, and shall extend to the aerodrome of intended landing, also covering the meteorological conditions expected between the aerodrome of intended landing and one alternate aerodrome designated by the operator. 9.1.3 Meteorological information supplied to operators and flight crew members shall be up to date and include the following information, a) Forecasts of 1) upper wind and upper-air temperature; 2) upper-air humidity; 3) geopotential altitude of flight levels; 4) flight level and temperature of tropopause; 5) direction, speed and flight level of maximum wind; 6) SIGWX phenomena; and 7) Cumulonimbus clouds, icing and turbulence. Note 1.— Forecasts of upper-air humidity and geopotential altitude of flight levels are used only in automatic flight planning and need not be displayed. Note 2.— Forecasts of cumulonimbus cloud, icing and turbulence are intended to be processed and, if necessary, visualized according to the specific thresholds relevant to user operations. Rev. _--Rev 4 , ---October 2024 32CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 b) METAR or SPECI (including trend forecasts as issued in accordance with regional air navigation agreement) for the aerodromes of departure and intended landing, and for take-off, en-route and destination alternate aerodromes; c) TAF or amended TAF for the aerodromes of departure and intended landing, and for take-off, en-route and destination alternate aerodromes; d) forecasts for take-off; e) SIGMET information and appropriate special air-reports relevant to the whole route; Note.— Appropriate special air-reports will be those not already used in the preparation of SIGMET. f) volcanic ash and tropical cyclone advisory information relevant to the whole route; g) as determined by regional air navigation agreement, GAMET area forecast and/or area forecasts for low-level flights in chart form preparedin support of the issuance of AIRMET information, and AIRMET information for low- level flights relevant to the whole route; h) aerodrome warnings for the local aerodrome; i) meteorological satellite images; j) ground-based weather radar information; and k) Space weather advisory information relevant to the whole route. 9.1.4 Forecasts listed under 9.1.3 a) shall be generated from the digital forecasts provided by the WAFCs whenever these forecasts cover the intended flight path in respect of time, altitude and geographical extent, unless otherwise agreed between the meteorological authority and the operator concerned. 9.1.5 When forecasts are identified as being originated by the WAFCs, no modifications shall be made to their meteorological content. 9.1.6 Charts generated from the digital forecasts provided by the WAFCs shall be made available, as required by operators, for fixed areas of coverage as shown in Appendix 8 of this CAR, Figures A8-1, A8-2 and A8-3. 9.1.7 When forecasts of upper wind and upper-air temperature listed under 9.1.3 a) 1) Are supplied in chart form, they shall be fixed time prognostic charts for flight levels as specified in Appendix 2 1.2.2 a). When forecasts of SIGWX phenomena listed under 9.1.3 a) 6) are supplied in chart form, they shall be fixed time prognostic charts for an atmospheric layer limited by flight levels as specified in Appendix 2, 1.3.2 and Appendix 5, 4.3.2. 9.1.8 The forecasts of upper wind and upper-air temperature and of SIGWX phenomena above flight level 100 requested for pre-flight planning and in- flight re-planning by the operator shall be supplied as soon as they become available, but not later than 3 hours before departure. Other meteorological Rev. _--Rev 4 , ---October 2024 33CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Information requested for pre-flight planning and in-flight re-planning by the operator shall be supplied as soon as is practicable. 9.1.9 When necessary, IMD shall initiate coordinating action with themeteorological authorities of other States with a view to obtaining from them the reports and/or forecasts required. 9.1.10 Meteorological information shall be supplied to operators and flight crew members at the location to be determined by the IMD, after consultation with the operators concerned and at the time agreed between the aerodrome meteorological office and the operator concerned. The service for pre-flight planning shall be confined to flights originating within India. At an aerodrome without an aerodrome meteorological office at the aerodrome, arrangements for the supply of meteorological information shall be as agreed between IMD and the operator concerned. 9.2 Briefing, consultation and display 9.2.1 Briefing and/or consultation shall be provided, on request, to flight crew members and/or other flight operations personnel. Its purpose shall be to supply the latest available information on existing and expected meteorological conditions along the route to be flown, at the aerodrome of intended landing, alternate aerodromes and other aerodromes as relevant, either to explain and amplify the information contained in the flight documentation or, as agreed between IMD and the operator concerned, in lieu of flight documentation. 9.2.2 Meteorological information used for briefing and consultation shall include any or all of the information listed in 9.1.3. 9.2.3 If the aerodrome meteorological office expresses an opinion on the development of the meteorological conditions at an aerodrome which differs appreciably from the aerodrome forecast included in the flight documentation, the attention of flight crew members shall be drawn to the divergence. The portion of the briefing dealing with the divergence shall be recorded at the time of briefing and this record shall be made available to the operator. 9.2.4 The required briefing, consultation, display and/or flight documentation shall normally be provided by the aerodrome meteorological office associated with the aerodrome of departure. At an aerodrome where these services are not available, arrangements to meet the requirements of flight crew members shall be as agreed between the meteorological authority and the operator concerned. In exceptional circumstances, such as an undue delay, the aerodrome meteorological office associated with the aerodrome shall provide or, if that is not practicable, arrange for the provision of a new briefing, consultation and/ or flight documentation as necessary. 9.2.5 The flight crew member or other flight operations personnel for whom briefing, consultation and/or flight documentation has been requested should visit the aerodrome meteorological office at the time agreed between the aerodrome meteorological office and the operator concerned. Where local Rev. _--Rev 4 , ---October 2024 34CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Circumstances at an aerodrome make personal briefing or consultation impracticable, the aerodrome meteorological office should provide those services by telephone or other suitable telecommunications facilities. 9.3 Flight documentation 9.3.1 Flight documentation to be made available shall comprise information listed under 9.1.3 a) 1) and 6), b), c), e), f) and, if appropriate, g) and k). However, flight documentation for flights of two hours’ duration or less, after a short stop or turnaround, shall be limited to the information operationally needed, as agreed between the meteorological authority and operator concerned, but in all cases the flight documentation shall at least comprise information on 9.1.3 b), c), e), f) and, if appropriate, g) and k). 9.3.2 Whenever it becomes apparent that the meteorological information to be included in the flight documentation will differ materially from that made available for pre-flight planning and in-flight re-planning, the operator shall be advised immediately and, if practicable, be supplied with the revised information as agreed between the operator and the aerodrome meteorological office concerned. 9.3.3 In cases where a need for amendment arises after the flight documentation has been supplied, and before take-off of the aircraft, the aerodrome meteorological office should, as agreed locally, issue the necessary amendment or updated information to the operator or to the local ATS unit, for transmission to the aircraft. 9.3.4 The IMD shall retain information supplied to flight crew members, either as printed copies or in computer files, for a period of at least 30 days from the date of issue. This information shall be made available, on request, for inquiries or investigations and, for these purposes, shall be retained until the inquiry or investigation is completed 9.4 Automated pre-flight information systems for briefing, consultation, flight planning and flight documentation 9.4.1 Where IMD uses automated pre-flight information systems to supply and display meteorological information to operators and flight crew members for self-briefing, flight planning and flight documentation purposes, the information supplied and displayed shall comply with the relevant provisions in 9.1 to 9.3 inclusive. 9.4.2 Automated pre-flight information systems providing for a harmonized, common point of access to meteorological information and aeronautical information services information by operators, flight crew members and other aeronautical personnel concerned should be as agreed between the meteorological authority and the civil aviation authority or the agency to which the authority to provide service has been delegated in accordance with CAR Section 9, Series ‘I’, Part- I, Para 2.1.1. Note.— The meteorological and aeronautical information services information Rev. _--Rev 4 , ---October 2024 35CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Concerned is specified in 9.1 to 9.3 and Appendix 8 and in CAR Section 9, Series ‘I’, Part-I, Para 8.1 and 8.2, respectively. 9.4.3 Where automated pre-flight information systems are used to provide for a harmonized, common point of access to meteorological information and aeronautical information services information by operators, flight crew members and other aeronautical personnel concerned, IMD shall remain responsible for the quality control and quality management of meteorological information provided by means of such systems in accordance with para 2.2.2. Note.— The responsibilities relating to aeronautical information services information and the quality assurance of the information are given in CAR Section 9, Series ‘I’ Part 1 Para 1, 2 and 3. 9.5 Information for aircraft in flight 9.5.1 Meteorological information for use by aircraft in flight shall be supplied by an aerodrome meteorological office or MWO to its associated ATS unit and through D-VOLMET or VOLMET broadcasts. Meteorological information for planning by the operator for aircraft in flight shall be supplied on request, as agreed between meteorological authority or authorities and the operator concerned. 9.5.2 Meteorological information for use by aircraft in flight shall be supplied to ATS units in accordance with the specifications of para 10. 9.5.3 Meteorological information shall be supplied through D-VOLMET or VOLMET broadcasts as determined by regional air navigation agreement, and in accordance with the specifications of para 11. 10. INFORMATION FOR AIR TRAFFIC SERVICES, SEARCH AND RESCUE SERVICES AND AERONAUTICAL INFORMATION SERVICES Note.— Please refer Appendix 9 of this CAR for Technical specifications and detailed criteria. 10.1 Information for air traffic services units 10.1.1 IMD shall designate an aerodrome meteorological office or MWO to be associated with each ATS unit. The associated aerodrome meteorological office or MWO shall, after coordination with the ATS unit, supply, or arrange for the supply of up-to-date meteorological information to the unit as necessary for the conduct of its functions. 10.1.2 An aerodrome meteorological office should be associated with an aerodrome control tower or approach control unit for the provision of meteorological information. 10.1.3 A MWO shall be associated with a FIC or an ACC for the provision of Rev. _--Rev 4 , ---October 2024 36CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Meteorological information. 10.1.4 Where, owing to local circumstances, it is convenient for the duties of an associated aerodrome meteorological office or MWO to be shared between two or more aerodrome meteorological offices or MWO, the division of responsibility should be determined by the meteorological authority in consultation with the appropriate ATS authority. 10.1.5 Any meteorological information requested by an ATS unit in connection with an aircraft emergency shall be supplied as rapidly as possible. 10.2 Information for search and rescue services units Aerodrome meteorological offices or MWO designated by the meteorological authority in accordance with regional air navigation agreement shall supply search and rescue services units with the meteorological information they require in a form established by mutual agreement. For that purpose, the designated aerodrome meteorological office or MWO shall maintain liaison with the search and rescue services unit throughout a search and rescue operation. 10.3 Information for aeronautical information services units The meteorological authority, in coordination with the appropriate civil aviation authority, shall arrange for the supply of up-to-date meteorological information to relevant aeronautical information services units, as necessary, for the conduct of their functions. 11. REQUIREMENTS FOR AND USE OF COMMUNICATIONS Note 1.— Technical specifications and detailed criteria related to this Para are given in Appendix 10 of this CAR. Note 2.— It is recognized that it is for each Contracting State to decide upon its own internal organization and responsibility for implementing the telecommunications facilities referred to in this Para. 11.1 Requirements for communications 11.1.1 Suitable telecommunications facilities shall be made available to permit aerodrome meteorological offices and, as necessary, aeronautical meteorological stations to supply the required meteorological information to ATS units on the aerodromes for which those offices and stations are responsible, and in particular to aerodrome control towers, approach control units and the aeronautical telecommunications stations serving these aerodromes. 11.1.2 Suitable telecommunications facilities shall be made available to permit MWO to supply the required meteorological information to ATS and search and rescue services units in respect of the FIR, control areas and search and rescue regions for which those offices are responsible, and in particular to FIC, ACC and rescue coordination Centre’s and the associated aeronautical Rev. _--Rev 4 , ---October 2024 37CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Telecommunications stations. 11.1.3 Suitable telecommunications facilities shall be made available to permit WAFC to supply the required WAFS products to aerodrome meteorological offices, meteorological authorities and other users 11.1.4 Telecommunications facilities between aerodrome meteorological offices and, as necessary, aeronautical meteorological stations and aerodrome control towers or approach control units shall permit communications bydirect speech, the speed with which the communications can be established being such that the required points may normally be contacted within approximately 15 seconds. 11.1.5 Telecommunications facilities between aerodrome meteorological offices or meteorological offices and FIC, ACC, rescue coordination centres and aeronautical telecommunications stations should permit: a) communications by direct speech, the speed with which the communications can be established being such that the required points may normally be contacted within approximately 15 seconds; and b) Printed communications, when a record is required by the recipients; the message transit time should not exceed 5 minutes. Note.— In 11.1.4 and 11.1.5, “approximately 15 seconds” refers to telephony communications involving switchboard operation and “5 minutes” refers to printed communications involving retransmission. 11.1.6 The telecommunications facilities required in accordance with Para 11.1.4 and 11.1.5 should be supplemented, as and where necessary, by other formsof visual or audio communications, for example, closed-circuit television or separate information processing systems. 11.1.7 As agreed between the meteorological authority and the operators concerned, provision should be made to enable operators to establish suitable telecommunications facilities for obtaining meteorological information from aerodrome meteorological offices or other appropriate sources. 11.1.8 Suitable telecommunications facilities shall be made available to permit meteorological offices to exchange operational meteorological information with other meteorological offices. 11.1.9 The telecommunications facilities used for the exchange of operational meteorological information should be the aeronautical fixed service or, for the exchange of non-time critical operational meteorological information, the public Internet, subject to availability, satisfactory operation and bilateral/multilateral and/or regional air navigation agreements. Note 1.— Aeronautical fixed service Internet-based services, operated by the WAFC, providing for global coverage are used to support the global exchanges of operational meteorological information. Note 2.— Guidance material on non-time-critical operational meteorological Rev. _--Rev 4 , ---October 2024 38CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24th March 2017 Information and relevant aspects of the public Internet is provided in the Guidelines on the Use of the Public Internet for Aeronautical Applications (Doc 9855). 11.2 Use of aeronautical fixed service communications and public Internet - Meteorological bulletins Meteorological bulletins containing operational meteorological information to be transmitted via the aeronautical fixed service or public Internet shall be originated by the appropriate meteorological office or aeronautical meteorological station. Note.— Meteorological bulletins containing operational meteorological information authorized for transmission via the aeronautical fixed service are listed in CAR Section 9, Series ‘D’, Part 3, Para 4 together with the relevant priorities and priority indicators. 11.3 Use of aeronautical fixed service communications - WAFS products World area forecast system products in digital form should be transmitted using binary data communications techniques. The method and channels used for the dissemination of the products should be as determined by regional air navigation agreement. 11.4 Use of aeronautical mobile service communications The content and format of meteorological information transmitted to aircraft and by aircraft shall be consistent with the provisions of this CAR. 11.5 Intentionally left blank. 11.6 Use of aeronautical broadcasting service — contents of VOLMET broadcasts 11.6.1 Continuous VOLMET broadcasts, normally on very high frequencies (VHF), shall contain current METAR and SPECI, together with trend forecasts where available. 11.6.2 Scheduled VOLMET broadcasts, normally on high frequencies (HF), shall contain current METAR and SPECI, together with trend forecasts where available and, where so determined by regional air navigation agreement, TAF and SIGMET. APPENDICES APPENDIX 1. FLIGHT DOCUMENTATION – MODEL CHARTS AND FORMS (See Para 9 of this CAR) MODEL A - OPMET information MODEL IS - Upper wind and temperature chart for standard isobaric surface Rev. _--Rev 4 , ---October 2024 39CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Example 1. Arrows, feathers and pennants (Mercator projection) Example 2. Arrows, feathers and pennants (Polar stereographic projection) MODEL SWH - Significant weather chart (high level) Example. Polar stereographic projection (showing the jet stream and vertical extent) MODEL SWM - Significant weather chart (medium level) MODEL SWL - Significant weather chart (low level) Example 1 Example 2 MODEL TCG - Tropical cyclone advisory information in graphical format MODEL VAG - Volcanic ash advisory information in graphical format Example 1 Mercator projection Example 2 Polar stereographic projection MODEL STC - SIGMET for tropical cyclone in graphical format MODEL SVA - SIGMET for volcanic ash in graphical format Example 1 Mercator projection Example 2 Polar stereographic projection MODEL SGE - SIGMET for phenomena other than tropical cyclone and volcanic ash in graphical format MODEL SN - Sheet of notations used in flight documentation Editorial Note.— Replace the existing MODEL VAG example in toto by the following two newexamples. VOLCANIC ASH ADVISORY INFORMATION IN GRAPHICAL FORMAT MODEL VAG Example 1. Mercator projection UPPER WIND AND TEMPERATURE CHART FOR STANDARD ISOBARIC SURFACE Rev. 2, 8th November 2018 40CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 VOLCANIC ASH ADVISORY INFORMATION IN GRAPHICAL FORMAT MODEL VAG Example 2. Polar stereographic projection UPPER WIND AND TEMPERATURE CHART FOR STANDARD ISOBARIC SURFACE Rev. 2, 8th November 2018 41CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Editorial Note.— Replace the existing MODEL SVA example in toto by the following two new examples. SIGMET FOR VOLCANIC ASH IN GRAPHICAL FORMAT MODEL SVA Example 1. Mercator projection UPPER WIND AND TEMPERATURE CHART FOR STANDARD ISOBARIC SURFACE Rev. 2, 8th November 2018 42CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 SIGMET FOR VOLCANIC ASH IN GRAPHICAL FORMAT MODEL SVA UPPER WIND AND TEMPERATURE CHART FOR STANDARD ISOBARIC SURFACE Rev. 2, 8th November 2018 43CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Example 2. Polar stereographic projection UPPER WIND AND TEMPERATURE CHART FOR STANDARD ISOBARIC SURFACE Rev. 2, 8th November 2018 44CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 OPMET INFORMATION MODEL A UPPER WIND AND TEMPERATURE CHART FOR STANDARD ISOBARIC SURFACE Rev. 2, 8th November 2018 45CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 MODEL IS Example 1. Arrows, feathers and pennants (Mercator projection) UPPER WIND AND TEMPERATURE CHART FOR STANDARD ISOBARIC SURFACE Rev. 2, 8th November 2018 46CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 MODEL IS Example 2. Arrows, feathers and pennants (Polar stereographic projection) SIGNIFICANT WEATHER CHART (HIGH LEVEL) Rev. 2, 8th November 2018 47CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 MODEL SWH Example — Polar stereographic projection (showing the jet stream vertical extend) SIGNIFICANT WEATHER CHART (MEDIUM LEVEL) MODEL SWM Rev. 2, 8th November 2018 48CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 March 2017 th SIGNIFICANT WEATHER CHART (LOW LEVEL) MODEL SWL Rev. 2, 8th November 2018 49CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 March 2017 th SIGNIFICANT WEATHER CHART (LOW LEVEL) MODEL SWL Rev. 2, 8th November 2018 50CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Example 2 TROPICAL CYCLONE ADVISORY INFORMATION IN GRAPHICAL FORMAT Rev. 2, 8 November 2018 51 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 MODEL TCG SIGMET FOR TROPICAL CYCLONE IN GRAPHICAL FORMAT MODEL STC Rev. 2, 8 November 2018 52 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 SIGMET FOR PHENOMENA OTHER THAN TROPICAL CYCLONE Rev. 2, 8 November 2018 53 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 AND VOLCANIC ASH IN GRAPHICAL FORMAT MODEL SGE Rev. 2, 8 November 2018 54 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 SHEET OF NOTATIONS USED IN FLIGHT DOCUMENTATION MODEL SN APPENDIX 2. TECHNICAL SPECIFICATIONS RELATED TO GLOBAL SYSTEMS, SUPPORTING CENTRES AND METEOROLOGICAL Rev. 2, 8 November 2018 55 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 OFFICES (See Para 3 of this CAR) 1 World Area Forecast System (WAFS) The technical specifications related to World Area Forecast System (WAFS) are stipulates in Appendix 2 of ICAO Annex 3 for the contracting states which haveaccepted responsibilities for providing a World Area Forecast Centers (WAFC). India is not a WAFC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with them and use its products/services effectively. 1.1 Formats and codes Intentionally left blank 1.2 Upper-air gridded forecasts 1.2.1 The forecasts of upper winds; upper-air temperature; and humidity; direction, speed and flight level of maximum wind; flight level and temperature of tropopause, areas of cumulonimbus clouds, icing,turbulence, and geopotential altitude of flight levels shall be prepared four times a day by a WAFC and shall be valid for fixed valid times at 6, 9, 12, 15, 18, 21, 24, 27, 30, 33 and 36 hours after the time (0000, 0600, 1200 and 1800 UTC) of the synoptic data on which the forecasts were based. Each forecast disseminated as soon as technically feasible as but not later than 5 hours after standard time of observation 1.1.2 The grid point forecasts prepared by a WAFC shall comprise: (a) wind and temperature data for flight levels 50 (850 hPa), 80 (750 hPa), 100 (700 hPa), 140 (600 hPa), 180 (500 hPa), 210 (450 hPa), 240 (400 hPa), 270 (350 hPa), 300 (300 hPa), 320 (275 hPa),340 (250 hPa), 360 (225 hPa), 390 (200 hPa), 410 (175 hPa), 450 (150 hPa), 480 (125 hPa) and 530 (100 hPa); (b) flight level and temperature of tropopause; (c) direction, speed and flight level of maximum wind; (d) humidity data for flight levels 50 (850 hPa), 80 (750 hPa), 100 (700 hPa), 140 (600 hPa) and180 (500 hPa); (e) horizontal extent and flight levels of base and top of cumulonimbus clouds; (f) icing for layers centered at flight levels 60 (800 hPa), 100 (700 hPa), 140 (600 hPa), 180 (500hPa), 240 (400 hPa) and 300 (300 hPa); Note-Layers centred at a flight level referred to in (f) have a depth of 100hpa g) Turbulence for layers centered at flight levels 100 (700 hpa), 140 (600 hpa), 180(500 hpa) 240 (400 hPa), 270 (350 hPa), 300 (300 hPa), 340 (250 hPa), 390 (200 hPa) and 450 (150 hPa); and Note .1— Layers centred at a flight level referred to in g) and h) have a depth of 100 hPa for flight levels below 240, then 50 hpa for flight levels 240 and above Note 2 turbulence referred to in g) above encompasses all types of turbulence, including clear-air and in-cloud turbulence Rev. 2, 8 November 2018 56 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 (H) Geopotential altitude data for flight levels 50 (850 hPa), 80 (750 hPa), 100 (700 hPa), 140 (600 hPa), 180 (500 hPa), 210 (450 hPa), 240 (400 hPa), 270 (350 hPa), 300 (300 hPa), 320 (275 hPa), 340 (250 hPa), 360 (225 hPa), 390 (200 hPa), 410 (175 hPa), 450 (150 hPa), 480 (125 hPa) and 530 (100 hPa). Note –the exact pressure levels (hpa) for a, b, f, g and h are provided in the manual of aeronautical meteorological practice (Doc 8896) 1.2.3 The foregoing grid point forecasts shall be issued by a WAFC in binary code form using theGRIB code form prescribed by the World Meteorological Organization (WMO). Note.— The GRIB code form is contained in the Manual on Codes (WMO-No. 306), Volume I.2, PartB — Binary Codes. 1.2.4 The foregoing grid point forecasts a, b, c, d) and h shall be prepared by a WAFC in aregular grid with a horizontal resolution of 1.25° of latitude and longitude. 1.2.5- The foregoing grid point forecasts e), f) and g) shall be prepared by a WAFC in a regular grid with a horizontal resolution of 0.25° of latitude and longitude. 1.2 Significant weather (SIGWX) forecasts 1.3.1 General provisions 1.3.1.1 Forecasts of significant en-route weather phenomena shall be prepared as SIGWX forecasts four times a day by a WAFC and shall be valid for fixed valid times at 24 hours after the time (0000, 0600, 1200 and 1800 UTC) of the synoptic data on which the forecasts were based. Each forecast shall be disseminated as soon as technically feasible but not later than 7 hours after standard time of observation under normal operations and not later than 9 hours after standard time of observation during backup operations. 1.3.1.2 SIGWX forecasts shall be issued in binary code form using the BUFR code form prescribedby WMO. Note. — The BUFR code form is contained in the Manual on Codes (WMO-No. 306), Volume I.2,Part B — Binary Codes. 1.3.1.3 Recommendation. — As of 4 November 2021, in addition to 1.3.1.2, SIGWX forecasts should be disseminated in IWXXM GML form. Note 1. — Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). Note 2. — Geography markup language (GML) is an encoding standard of the Open Geospatial Consortium (OGC). 2. Aerodrome Meteorological Offices 2.1 Use of WAFS products 2.1.1 Aerodrome meteorological offices shall use forecasts issued by the Rev. 2, 8 November 2018 57 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 WAFCs in the preparation of flight documentation, whenever these forecasts cover the intended flight path in respect of time, altitude and geographical extent, unless otherwise agreed between the meteorological authority and the operator concerned. 1.2.2 In order to ensure uniformity and standardization of flight documentation, the WAFS GRIB and BUFR data received and, as of 4 November 2021, IWXXM data received, shall be decoded into standard WAFS charts in accordance with relevant provisions in this CAR, and the meteorological content and identification of the originator of the WAFS forecasts shall not be amended. 2.2 Notification of WAFC concerning significant discrepancies Aerodrome meteorological offices using WAFS BUFR or, as of 4 November 2021, IWXXM data shall notify the WAFC concerned immediately if significant discrepancies are detected orreported in respect of WAFS SIGWX forecasts concerning: a) icing, turbulence, cumulonimbus clouds that are obscured, frequent, embedded or occurring at a squall line, and sandstorms/dust storms; and b) Volcanic eruptions or a release of radioactive materials into the atmosphere, of significance to aircraft operations. Rev. 2, 8 November 2018 58 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 The WAFC receiving the message shall acknowledge its receipt to the originator, together with brief comment on the report and any action taken, using the same means of communication employed by the originator. Note. — Guidance on reporting significant discrepancies is provided in the Manual of Aeronautical Meteorological Practice (Doc 8896). 3 Volcanic Ash Advisory Centre’s (VAAC) 3.1 Volcanic ash advisory information The technical specifications related to Volcanic Ash Advisory center’s (VAACs) are stipulates in Appendix 2 of ICAO Annex 3 for the contracting states which have accepted responsibilities for providing a VAAC. India is not a VAAC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with VAAC and use its products/services effectively. 4. State Volcano Observatories 4.1 Information from State volcano observatories ICAO stipulates in Appendix 2 of Annex 3 the technical specifications required of contracting states which maintain volcano observatories monitoring active volcanoes. India does not maintain any volcano observatories. However, the Service Provider shall have to be familiar with the roles/functions of volcano observatories in the region so as to be able to interact with them and use its products/services effectively. 5 Tropical Cyclone Advisory Centre’s (TCAC) 5.1 Tropical cyclone advisory information 5.1.1 The advisory information on tropical cyclones shall be issued for tropicalcyclones when the maximum of the 10-minute mean surface wind speed is expected to reach or exceed 17 m/s (34 kt) during the period covered by the advisory. 5.1.2 The advisory information on tropical cyclones disseminated in abbreviated plain language, using approved ICAO abbreviations and numerical values of self-explanatorynature, shall be in accordance with the template shown in Table A2-2. 5.1.3 Until 4 November 2020, tropical cyclone advisory information should be disseminated in IWXXM GML form in addition to the issuance of this advisory information in accordance with 5.1.2. 5.1.4 As of 5 November 2020, tropical cyclone advisory Centre’s shall disseminate tropicalcyclone advisory information in IWXXM GML form in addition to the dissemination ofthis advisory information in abbreviated plain language in accordance with 5.1.2. Rev. 2, 8 November 2018 59 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Note. — The technical specifications for IWXXM are contained in the Manual on Codes (WMO-No. 306), Volume I.3, Part D — Representation Derived from Data Models. Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). 5.1.5 The tropical cyclone advisory information listed in Table A2-2, when prepared in graphical format, shall be as specified in Appendix 1 and issued using the PNG format. 6. Space Weather Centre The technical specifications related to SWXC are stipulates in Chapter 3, para 3.8, Appendix 2 and Attachment E of ICAO Annex 3 for the contracting states which have accepted responsibilities to monitor and provide advisory information on space weather. India is not a SWXC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with SWXC and use its products/services effectively. Rev. 2, 8 November 2018 60 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Table A2-1. Template for advisory message for volcanic ash Key: M = inclusion mandatory, part of every message; O = inclusion optional; C = inclusion conditional, included whenever applicable; = = a double line indicates that the text following it should be placed on the subsequentline. Note 1. — The ranges and resolutions for the numerical elements included in advisory messages forvolcanic ash are shown in Appendix 6, Table A6-4. Note 2. — The explanations for the abbreviations can be found in the Procedures for Air NavigationServices — ICAO Abbreviations and Codes (PANS-ABC, Doc 8400). Note 3. — Inclusion of a colon after each element heading is mandatory. Note 4.— The numbers 1 to 19 are included only for clarity and are not part of the advisory message,as shown in the example. Element Detailed content Template(s) Examples … … … … … 5 Name of Name and IAVCEI2 VOLCANO: nnnnnnnnnnnnnnnnnnnnnn VOLCANO KARYMSKY volcano (M) number of volcano [nnnnnn] : 300130 or UNKNOWN or UNNAMED UNNAMED UNKNOWN 6 … … … … … 7 State or region State, or region if AREA: nnnnnnnnnnnnnnnn AREA: RUSSIA (M) ash is not reported or over a State UNKNOWN UNKNOWN 8 Summit Summit elevation in SUMMIT ELEV: nnnnM (or nnnnnFT) SUMMIT 1536M elevation (M) m (or ft) or ELEV: SFC SFC or UNKNOWN 9 … … … … … 10 Information Information source INFO SOURCE: Free text up to 32 characters INFO HIMAWARI-8 source (M) using free text SOURCE: KVERT KEMSD 11 … … … … … 12 Eruption details Eruption details ERUPTION Free text up to 64 characters ERUPTIO ERUPTION AT (M) (including date/time DETAILS: or N 20080923/0000Z of eruption(s)) UNKNOWN DETAILS: FL300 REPORTED Element Detailed content Template(s) Examples NO ERUPTION – RE- SUSPENDED VA6 UNKNOWN … … … … … … 18 Remarks (M) Remarks, as RMK: Free text up to 256 characters RMK: LATEST REP FM necessary or KVERT (0120Z) NIL INDICATES ERUPTION HAS CEASED. TWO DISPERSING VA CLD ARE EVIDENT ON SATELLITE IMAGERY RE-SUSPENDED VA6, 7 NIL 19 … … … … … Rev. 2, 8 November 2018 61 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Notes.— . . . 6. To be included (as free text) only for those situations where volcanic ash has been re-suspended. 7. To be included (as free text) where space in the remarks section allows. Example A 2-1. Advisory message for volcanic ash VA ADVISORY DTG: 20080923/0130Z VAAC: TOKYO VOLCANO: KARYMSKY 300130 PSN: N5403 E15927 AREA: RUSSIA SUMMIT ELEV: 1536M ADVISORY NR: 2008/4 INFO SOURCE: HIMAWARI-8 KVERT KEMSD … Table A2-2. Template for advisory message for tropical cyclones Key: M = inclusion mandatory, part of every message; C = inclusion conditional, including whenever applicable; O = inclusion optional; = = a double line indicates that the text following it should be placed on the subsequent line. Element Detailed content Template(s) Examp les 1 Identification of Type of message TC ADVISORY TC ADVISORY the type of message 2 Status indicator Indicator of test or exercise STATUS: TEST or EXER STATUS: TEST (C)1 STATUS: EXER 3 Time of origin Year, month, day and time DTG: nnnnnnnn/nnnnZ DTG 20040925/19600Z (M) in UTC of issue Rev. 2, 8 November 2018 62 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 4 Name of TCAC Name of TCAC (location TCAC: nnnn or nnnnnnnnnn TCAC: YUFO1 (M) indicator or full name) TCAC: MIAMI 5 Name of tropical Name of tropical cyclone or TC: nnnnnnnnnnnn or NN TC: GLORIA cyclone (M) “NN” for unnamed tropical cyclone 6 Advisory Advisory number: Year Advisory nnnn/[n][n]nn Advisory NR: 2004/1301 number (M) in full and message NR: number(separate sequence for each cyclone) 7 Observed Day and time (in UTC) and OBS nn/nnnnZ OBS 25/1800Z Position of the Position of the centre of the PSN: Nnn[nn] or Snn[nn] Wnnn[nn] or PSN: N2706 W07306 centre (M) tropical cyclone (in degrees Ennn[nn] and minutes) Location of CB cloud (referring to CB: WI nnnKM (or nnnNM) OF TC CENTRE 8 Observed CB CB: WI 250NM OF TC latitude and longitude (in degrees or cloud (C O) CENTRE TOP FL500 and minutes)) and vertical extent WI4 Nnn[nn] or Snn[nn] Wnnn[nn] or (flight level) Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or NIL Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] TOP [ABV or BLW] FLnnn 9 10 Changes in Changes of maximum surface INTST INTSF or INTST CHANGE: INTSF intensity (M) wind speed at time of CHANGE WKN or observation NC Example A2-2. Advisory message for tropical cyclones TC ADVISORY 20040925/19600Z DTG: YUFO TCAC: GLORIA TC: 2004/13 ADVISORY NR: 25/1800Z N2706 W07306 OBS PSN: WI 250NM OF TC CENTRE CB: MOV: NW 20KMH INTST CHANGE III INTSF C: 965HPA MAX WIND: 25MPS FCST PSN +6 HR: 25/2200Z N2748 W07350 FCST MAX WIND +6 HR: 22MPS FCST PSN +12 HR: 26/0400Z N2830 W07430 FCST MAX WIND +12 HR: 22MPS FCST PSN +18HR: 26/1000Z N2852 W07500 FCST MAX WIND +18 HR: 21MPS FCST PSN +24HR: 26/1600Z N2912 W07530 FCST MAX WIND +24 HR: 20MPS RMK: NIL 20040925/2000Z Rev. 2, 8 November 2018 63 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 NXT MSG: Table A2-3. Template for advisory message for space weather information Element Detailed content Template(s) Examples 1 … … … … … … … … … 7 Space weather Effect and intensity of SWX EFFECT: HF COM MOD or SEV [AND]3 or SWX EFFECT: HF COM MOD effect and the space weather SATCOM MOD or SEV [AND]3 or intensity (M) phenomena GNSS MOD or SEV SATCOM SEV [AND]3 or RADIATION4 MOD or SEV GNSS SEV HF COM MOD AND SATCOM MOD AND GNSS MOD RADIATION MOD SATCOM SEV 8 Observed or Day and time (n UTC) OBS nn/nnnnZ OBS SWX:: 08/0100Z DAYLIGHT expected space of observed (or FCST) SWX: DAYLIGHT SIDE or SIDE weather phenomena (or HNH and/or MNH and/or EQN and/or phenomena (M) forecast if EQS and/or MSH and/or HSH Wnnn(nn) 08/0100Z HNH HSH phenomena have yet or Ennn(nn) – Wnnn(nn) or Ennn(nn) to occur); and/or E18000 – W18000 ABV FLnnn or FLnnn – nnn and/or Horizontal extent34 Nnn[nn] or Snn[nn] Wnnn[nn] orEnnn[nn] 08/0100Z HNH HSH Rev. 2, 8 November 2018 64 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 (latitude bands and – Nnn[nn] or Snn[nn] Wnnn[nn] or W18000 – W09000 longitude in degrees) Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] ABV FL350 and/or altitude of or Ennn[nn] – [Nnn[nn] or Snn[nn] space weather Wnnn[nn] or Ennn[nn] – Nnn[nn] or 08/0100Z S2000 phenomena Snn[nn] Wnnn[nn] or Ennn[nn]] W17000 – S2000 or NO SWX EXP W13000 – S1000 W13000 – S1000 W17000 – S2000 W17000 NO SWX EXP 9 Forecast of the Day and time (in UTC) FCST SWX +6 HR: nn/nnnnZ FCST SWX +6 HR: 08/0700Z DAYLIGHT phenomena (+6 (6 hours from the time DAYLIGHT SIDE or SIDE Element Detailed content Template(s) Examples HR) (M) given in Item 8, rounded HNH and/or MNH and/or EQN and/or to the next full hour); EQS and/or MSH and/or HSH 08/0700Z HNH HSH Wnnn(nn) or Ennn(nn) – Wnnn(nn) or Ennn(nn) W18000 – W09000 ABV Forecast extent and/or and/or FL350 altitude of the space ABV FLnnn or FLnnn – nnn and/or weather phenomena for Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – 08/0700Z HNH HSH that fixed valid time Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – E18000 – W18000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – NO SWX EXP Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or NOT AVBL NO SWX EXP or NOT AVBL 10 Forecast of the Day and time (in UTC) FCST SWX +12 HR: nn/nnnnZ FCST SWX +12 HR: 08/1300Z DAYLIGHT phenomena (+12 (12 hours from the time DAYLIGHT SIDE or SIDE HR) (M) given in Item 8, rounded HNH and/or MNH and/or EQN and/or to the next full hour). EQS and/or MSH and/or HSH 08/1300Z HNH HSH Wnnn(nn) or Ennn(nn) – Wnnn(nn) or Ennn(nn) W18000 – W09000 ABV Forecast extent and/or and/or FL350 altitude of the space ABV FLnnn or FLnnn – nnn and/or weather phenomena for Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – 08/1300Z HNH HSH that fixed valid time Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – E18000 – W18000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – NO SWX EXP Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or NOT AVBL NO SWX EXP or NOT AVBL 11 Forecast of the Day and time (in UTC) FCST SWX +18 HR: nn/nnnnZ FCST SWX +18 HR: 08/1900Z DAYLIGHT phenomena (+18 (18 hours from the time DAYLIGHT SIDE or SIDE HR) (M) given in Item 8, rounded HNH and/or MNH and/or EQN and/or to the next full hour). EQS and/or MSH and/or HSH 08/1900Z HNH HSH Wnnn(nn) or Ennn(nn) – Wnnn(nn) or Ennn(nn) W18000 – W09000 ABV Forecast extent and/or and/or FL350 altitude of the space ABV FLnnn or FLnnn – nnn and/or weather phenomena for Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – 08/1900Z HNH HSH that fixed valid time Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – E18000 – W18000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – NO SWX EXP Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or NOT AVBL NO SWX EXP or NOT AVBL Rev. 2, 8 November 2018 65 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 12 Forecast of the Day and time (in UTC) FCST SWX +24 HR: nn/nnnnZ FCST SWX +24 HR: 09/0100Z DAYLIGHT phenomena (+24 (24 hours from the time DAYLIGHT SIDE or SIDE HR) (M) given in Item 8, rounded HNH and/or MNH and/or EQN and/or to the next full hour). EQS and/or MSH and/or HSH 09/0100Z HNH HSH Wnnn(nn) or Ennn(nn) – Wnnn(nn) or Ennn(nn) W18000 – W09000 ABV Forecast extent and/or and/or FL350 altitude of the space ABV FLnnn or FLnnn – nnn and/or weather phenomena for Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – 09/0100Z HNH HSH that fixed valid time Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – E18000 – W18000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – NO SWX EXP Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or NOT AVBL NO SWX EXP or NOT AVBL … … … … … … … … 14 Next advisory (M) Year, month, day and NXT ADVISORY: nnnnnnnn/nnnnZ NXT ADVISORY: 20161108/0700Z time in UTC or NO FURTHER ADVISORIES NO FURTHER Element Detailed content Template(s) Examples or ADVISORIES WILL BE ISSUED BY nnnnnnnn/nnnnZ WILL BE ISSUED BY 20210726/1800Z 1. Used only when the message issued to indicate that a test or an exercise is taking place. When the word “TEST” or the abbreviation “EXER” is included, the message may contain information that should not be used operationally or will otherwise end immediately after the word "TEST". [Applicable 7 November 2019] 2. Ficticious location. 3 One or more effects with the same intensity may be combined. 4. One or more latitude ranges may be included in the space weather advisory information. Example A2-3: Space weather advisory message (GNSS and HF COM effects) Intentionally left blank Example A2-4: Space weather advisory message (RADIATION effects) Intentionally left blank Example A2-5: Space weather advisory message (HF COM effects) Intentionally left blank Rev. 2, 8 November 2018 66 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 APPENDIX 3. TECHNICAL SPECIFICATIONS RELATED TO METEOROLOGICAL OBSERVATIONS AND REPORTS (See Para 4 of this CAR.) 1 General provision related to meteorological observations 1.1 Meteorological Observation 1.1.1 The meteorological instruments used at an aerodrome should be situated in such a way as to supply data which are representative of the area for which the measurements are required. Note.— Specifications concerning the siting of equipment and installations on operational areas, aimed at reducing the hazard to aircraft to a minimum, are contained in Annex 14, Volume I, Para 9. 1.1.2 Meteorological instruments at aeronautical meteorological stations should be exposed, operated and maintained in accordance with the practices, procedures and specifications promulgated by the World Meteorological Organization (WMO). 1.1.3 The observers at an aerodrome should be located, in so far as is practicable, so as to supply data which are representative of the area for which the observations are required. 1.1.4 Where automated equipment forms part of an integrated semi- automatic observing system, displays of data which are made available to the local ATS Rev. 2, 8 November 2018 67 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 units should be a subset of and displayed parallel to those available in the local meteorological service unit. In those displays, each meteorological element should be annotated to identify, as appropriate, the locations for which the element is representative. 2 General criteria related to meteorological reports 2.1 Format of meteorological reports 2.1.1 Local routine and special reports shall be issued in abbreviated plain language, in accordance with the template shown in Table A3-1. 2.1.2 METAR and SPECI shall be issued in accordance with the template shown in Table A3-2 and disseminated in the METAR and SPECI code forms prescribed by the WMO. Note.— The METAR and SPECI code forms are contained in WMO Publication No. 306, Manual on Codes, Volume I.1, Part A — Alphanumeric Codes. 2.1.3 Until 4 November 2020, METAR and SPECI should be disseminated in IWXXM GML form in addition to the dissemination of the METAR and SPECI in accordance with 2.1.2. 2.1.3 As of 5 November 2020, METAR AND SPECI shall be disseminate in IWXXM Rev. 2, 8 November 2018 68 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 GML form in addition to the dissemination of the METAR AND SPECI in accordance with 2.1.2. Note.— The technical specifications for IWXXM are contained in the Manual on Codes (WMO-No. 306), Volume I.3, Part D — Representation Derived from Data Models. Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). 2.2 Use of CAVOK 2.2.1 When the following conditions occur simultaneously at the time of observation: a) visibility, 10 km or more, and the lowest visibility is not reported; Note 1.— In local routine and special reports, visibility refers to the value(s) to be reported in accordance with Appendix 3, Para 4.2.4.2 and 4.2.4.3; in METAR and SPECI, visibility refers to the value(s) to be reported in accordance with Appendix 3, Para 4.2.4.4. Note 2. – The lowest visibility is reported in accordance with Appendix 3, Para 4.2.4.4 a). b) no cloud of operational significance; c) no weather of significance to aviation as given in Appendix 3, Para 4.4.2.3, 4.4.2.5 and 4.4.2.6; Information on visibility, runway visual range, present weather and cloud amount, cloud type and height of cloud base shall be replaced in all meteorological reports by the term “CAVOK”. 2.3 Criteria for issuance of local special reports and SPECI 2.3.1 The list of criteria for the issuance of local special reports shall include the following: a) those values which most closely correspond with the operating minima of the operators using the aerodrome; b) those values which satisfy other local requirements of the air traffic services units and of the operators; c) an increase in air temperature of 2°C or more from that given in the latest report, or an alternative threshold value as agreed between the meteorological authority, the appropriate ATS authority and the operators concerned; d) the available supplementary information concerning the occurrence of significant meteorological conditions in the approach and climb-out areas as given in Table A3-1; e) when noise abatement procedures are applied in accordance with the PANS-ATM (Doc 4444) and the variation from the mean surface wind speed (gusts) has changed by 2.5 m/s (5 kt) or more from that at the time of the latest report, the mean speed before and/or after the change being 7.5 m/s (15 kt) or more; and f) Those values which constitute criteria for SPECI. Rev. 2, 8 November 2018 69 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 2.3.2 Where required in accordance with Para 4, 4.4.2 b), SPECI shall be issued whenever changes in accordance with the following criteria occur: a) when the mean surface wind direction has changed by 60° or more from that given in the latest report, the mean speed before and/or after the change being 5 m/s (10 kt) or more; b) when the mean surface wind speed has changed by 5 m/s (10 kt) or more from that given in the latest report; c) when the variation from the mean surface wind speed (gusts) has increased by 5 m/s (10 kt) or more from that at the time of the latest report,the mean speed before and/or after the change being 7.5 m/s (15 kt) or more; d) when the onset, cessation or change in intensity of any of the following weather phenomena occurs: — freezing precipitation — moderate or heavy precipitation (including showers thereof) — thunderstorm (with precipitation) e) when the onset or cessation of any of the following weather phenomena occurs: — freezing fog — thunderstorm (without precipitation) f) when the amount of a cloud layer below 450 m (1 500 ft) changes: 1) from SCT or less to BKN or OVC; or 2) from BKN or OVC to SCT or less; 2.3.3 Where required in accordance with Para 4, Sub Para 4.4.2 b), SPECI should be issued whenever changes in accordance with the following criteria occur: a) when the wind changes through values of operational significance. The threshold values should be established by the meteorological authority in consultation with the appropriate ATS authority and operators concerned, taking into account changes in the wind which would: 1) require a change in runway(s) in use; and 2) indicate that the runway tailwind and crosswind components have changed through values representing the main operating limits for typical aircraft operating at the aerodrome; b) when the visibility is improving and changes to or passes through one or more of the following values, or when the visibility is deteriorating and passes through one or more of the following values: 1) 800, 1500 or 3000 m; and 2) 5000 m, in cases where significant numbers of flights are operated in accordance with the visual flight rules; Rev. 2, 8 November 2018 70 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Note 1.— In local special reports, visibility refers to the value(s) to be reported in accordance with Appendix 3, 4.2.4.2 and 4.2.4.3; in SPECI, visibility refers to the value(s) to be reported in accordance with Appendix 3,4.2.4.4. Note 2.— Visibility refers to “prevailing visibility” except in the case where only the lowest visibility is reported in accordance with Appendix 3, 4.2.4.4 b). c) when the runway visual range is improving and changes to or passes through one or more of the following values, or when the runway visual range is deteriorating and passes through one or more of the following values: 50, 175, 300, 550 or 800 m; d) when the onset, cessation or change in intensity of any of the following weather phenomena occurs: — dust storm — sandstorm — funnel cloud (tornado or waterspout); e) when the onset or cessation of any of the following weather phenomena occurs: — low drifting dust, sand or snow — blowing dust, sand or snow — squall; f) when the height of base of the lowest cloud layer of BKN or OVC extent is lifting and changes to or passes through one or more of the following values, or when the height of base of the lowest cloud layer of BKN or OVC extent is lowering and passes through one or more of the following values: 1) 30, 60, 150 or 300 m (100, 200, 500 or 1 000 ft); and 2) 450 m (1500 ft) in cases where significant numbers of flights are operated in accordance with the visual flight rules; g) when the sky is obscured and the vertical visibility is improving and changes to or passes through one or more of the following values, or when the vertical visibility is deteriorating and passes through one or more of the following values: 30, 60, 150 or 300 m (100, 200, 500 or 1000 ft); and h) any other criteria based on local aerodrome operating minima, as agreed between the meteorological authority and the operators concerned. Note.— Other criteria based on local aerodrome operating minima are to be considered in parallel with similar criteria for the inclusion of change groups and for the amendment of TAF developed in response to Appendix 5, 1.3.2 j). 2.3.4 When a deterioration of one weather element is accompanied by an improvement in another element, a single SPECI shall be issued; it shall then be treated as a deterioration report. 3 Dissemination of meteorological reports Rev. 2, 8 November 2018 71 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 3.1 METAR and SPECI 3.1.1 METAR and SPECI shall be disseminated to international OPMET databanks and the Centre’s designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services, in accordance with regional air navigation agreement. 3.1.2 METAR and SPECI shall be disseminated to other aerodromes in accordance with regional air navigation agreement. 3.1.3 SPECI representing a deterioration in conditions shall be disseminated immediately after the observation. A SPECI representing a deterioration of one weather element and an improvement in another element shall be disseminated immediately after the observation. 3.1.4 Recommendation.— A SPECI representing an improvement in conditions should be disseminated only after the improvement has been maintained for 10 minutes; it should be amended before dissemination, if necessary, to indicate the conditions prevailing at the end of that 10-minute period. 3.2 Local routine and special reports 3.2.1 Local routine reports shall be transmitted to local air traffic services units and shall be made available to the operators and to other users at the aerodrome. 3.2.2 Local special reports shall be transmitted to local air traffic services units as soon as the specified conditions occur. However, as agreement between the meteorological authority and the appropriate ATS authority, they need not be issued in respect of: a) any element for which there is in the local air traffic services unit a display corresponding to the one in the meteorological station, and where arrangements are in force for the use of this display to update information included in local routine and special reports; and b) Runway visual range, when all changes of one or more steps on the reporting scale in use are being reported to the local air traffic services unit by an observer on the aerodrome. Local special reports shall also be made available to the operators and to other users at the aerodrome. 4 Observing and reporting of meteorological elements Introductory Note.— Selected criteria applicable to meteorological information referred to under 4.1 to 4.8 for inclusion in aerodrome reports are given in tabular form at Attachment C. 4.1 Surface wind 4.1.1 Siting 4.1.1.1 Surface wind should be observed at a height of 10 ± 1 m (30 ± 3 ft) above the ground. Rev. 2, 8 November 2018 72 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 4.1.1.2 Representative surface wind observations should be obtained by the use of sensors appropriately sited. Sensors for surface wind observations for local routine and special reports should be sited to give the best practicable indication of conditions along the runway and touchdown zones. At aerodromes where topography or prevalent weather conditions cause significant differences in surface wind at various sections of the runway, additional sensors should be provided. Note.— Since, in practice, the surface wind cannot be measured directly on the runway, surface wind observations for take-off and landing are expected to be the best practicable indication of the winds which an aircraft will encounter during take-off and landing. 4.1.2 Displays 4.1.2.1 Surface wind displays relating to each sensor shall be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units shall relate to the same sensors, and where separate sensors are required as specified in 4.1.1.2, the displays shall be clearly marked to identify the runway and section of runway monitored by each sensor. 4.1.2.2 The mean values of, and significant variations in, the surface wind direction and speed for each sensor should be derived and displayed by automated equipment. 4.1.3 Averaging 4.1.3.1 The averaging period for surface wind observations shall be: a) 2 minutes for local routine and special reports and for wind displays in air traffic services units; and b) 10 minutes for METAR and SPECI, except that when the 10-minute period includes a marked discontinuity in the wind direction and/or speed, only data occurring after the discontinuity shall be used for obtaining mean values; hence, the time interval in these circumstances shall be correspondingly reduced. Note.— A marked discontinuity occurs when there is an abrupt and sustained change in wind direction of 30° or more, with a wind speed of 5 m/s (10 kt) before or after the change, or a change in wind speed of 5 m/s (10 kt) or more, lasting at least 2 minutes. 4.1.3.2 The averaging period for measuring variations from the mean wind speed (gusts) reported in accordance with 4.1.5.2 c) should be 3 seconds for local routine and special reports and for METAR and SPECI and for wind displays used for depicting variations from the mean wind speed (gusts) in air traffic services units. 4.1.4 Accuracy of measurement The reported direction and speed of the mean surface wind, as well as Rev. 2, 8 November 2018 73 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Variations from the mean surface wind, should meet the operationally desirable accuracy of measurement as given in Attachment A. 4.1.5 Reporting 4.1.5.1 In local routine and special reports and in METAR and SPECI, the surface wind direction and speed shall be reported in steps of 10 degrees true and 1 metre per second (or 1 knot), respectively. Any observed value that does not fit the reporting scale in use shall be rounded to the nearest step in the scale. 4.1.5.2 In local routine and special reports and in METAR and SPECI: a) the units of measurement used for the wind speed shall be indicated; b) variations from the mean wind direction during the past 10 minutes shall be reported as follows, if the total variation is 60° or more: 1) when the total variation is 60° or more and less than 180° and the wind speed is 1.5 m/s (3 kt) or more, such directional variations shall be reported as the two extreme directions between which the surface wind has varied; 2) when the total variation is 60° or more and less than 180° and the wind speed is less than 1.5 m/s (3 kt), the wind direction shall be reported as variable with no mean wind direction; or 3) when the total variation is 180° or more, the wind direction shall be reported as variable with no mean wind direction; c) variations from the mean wind speed (gusts) during the past 10 minutes shall be reported when the maximum wind speed exceeds the mean speed by: 1) 2.5 m/s (5 kt) or more in local routine and special reports when noise abatement procedures are applied in accordance with the PANS-ATM (Doc 4444); or 2) 5 m/s (10 kt) or more otherwise; d) when a wind speed of less than 0.5 m/s (1 kt) is reported, it shall be indicated as calm; e) when a wind speed of 50 m/s (100 kt) or more is reported, it shall be indicated to be more than 49 m/s (99 kt); and f) When the 10-minute period includes a marked discontinuity in the wind direction and/or speed, only variations from the mean wind direction and mean wind speed occurring since the discontinuity shall be reported. Note.— See note under 4.1.3.1. 4.1.5.3 In local routine and special reports: Rev. 2, 8 November 2018 74 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 a) if the surface wind is observed from more than one location along the runway, the locations for which these values are representative shall be indicated; b) when there is more than one runway in use and the surface wind related to these runways is observed, the available wind values for each runway shall be given, and the runways to which the values refer shall be reported; c) when variations from the mean wind direction are reported in accordance with 4.1.5.2 b) 2), the two extreme directions between which the surface wind has varied shall be reported; and d) When variations from the mean wind speed (gusts) are reported in accordance with 4.1.5.2 c), they shall be reported as the maximum and minimum values of the wind speed attained. 4.1.5.4 In METAR and SPECI, when variations from the mean wind speed (gusts) are reported in accordance with 4.1.5.2 c), the maximum value of the wind speed attained shall be reported. 4.2 Visibility 4.2.1 Siting 4.2.1.1 When instrumented systems are used for the measurement of visibility, the visibility should be measured at a height of approximately 2.5 m (7.5 ft) above the runway. 4.2.1.2 When instrumented systems are used for the measurement of visibility, representative visibility observations should be obtained by the use of sensors appropriately sited. Sensors for visibility observations for local routine and special reports should be sited to give the best practicable indications of visibility along the runway and touchdown zone. 4.2.2 Displays When instrumented systems are used for the measurement of visibility, visibility displays relating to each sensor should be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units should relate to the same sensors, and where separate sensors are required as specified in 4.2.1, the displays should be clearly marked to identify the area, e.g. runway and section of runway, monitored by each sensor. 4.2.3 Averaging When instrumented systems are used for the measurement of visibility, their output should be updated at least every 60 seconds to permit provision of current representative values. The averaging period should be: a) 1 minute for local routine and special reports and for visibility displays in air traffic services units; and Rev. 2, 8 November 2018 75 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 b) 10 minutes for METAR and SPECI, except that when the 10-minute period immediately preceding the observation includes a marked discontinuity in the visibility, only those values occurring after the discontinuity should be used for obtaining mean values. Note.— A marked discontinuity occurs when there is an abrupt and sustained change in visibility, lasting at least 2 minutes, which reaches or passes through criteria for the issuance of SPECI reports given in 2.3. 4.2.4 Reporting 4.2.4.1 In local routine and special reports and in METAR and SPECI, the visibility shall be reported in steps of 50 m when the visibility is less than 800 m; in steps of 100 m, when it is 800 m or more but less than 5 km; in kilometer steps, when the visibility is 5 km or more but less than 10 km; and it shall be given as 10 km when the visibility is 10 km or more, except when the conditions for the use of CAVOK apply. Any observed value which does not fit the reporting scale in use shall be rounded down to the nearest lower step in the scale. Note.— Specifications concerning the use of CAVOK are given in 2.2. 4.2.4.2 In local routine and special reports, visibility along the runway(s) shall be reported together with the units of measurement used to indicate visibility. 4.2.4.3 In local routine and special reports, when instrumented systems are used for the measurement of visibility: a) if the visibility is observed from more than one location along the runway as specified in Para 4, 4.6.2.2, the values representative of the touchdown zone should be reported first, followed, as necessary, by the values representative of the mid-point and stop-end of the runway, and the locations for which these values are representative should be indicated; and b) When there is more than one runway in use and the visibility is observed related to these runways, the available visibility values for each runway should be reported, and the runways to which the values refer should be indicated. 4.2.4.4 In METAR and SPECI, visibility should be reported as prevailing visibility, as defined in Para 1. When the visibility is not the same in different directions and a) when the lowest visibility is different from the prevailing visibility, and 1) less than 1500 m or 2) less than 50 per cent of the prevailing visibility and less than 5000 m; the lowest visibility observed should also be reported and, when possible, its general direction in relation to the aerodrome reference point indicated by reference to one of the eight points of the compass. If the lowest visibility is observed in more than one direction, then the most operationally significant direction should be reported; and b) When the visibility is fluctuating rapidly, and the prevailing visibility cannot be determined, only the lowest visibility should be reported, with no indication of direction. 4.3 Runway visual range Rev. 2, 8 November 2018 76 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 4.3.1 Siting 4.3.1.1 Runway visual range should be assessed at a height of approximately 2.5 m (7.5 ft) above the runway for instrumented systems or assessed at a height of approximately 5 m (15 ft) above the runway by a human observer. 4.3.1.2 Runway visual range should be assessed at a lateral distance from the runway Centre line of not more than 120 m. The site for observations to be representative of the touchdown zone should be located about 300 m along the runway from the threshold. The sites for observations to be representative of the mid-point and stop-end of the runway should be located at a distance of 1000 to 1500 m along the runway from the threshold and at a distance of about 300 m from the other end of the runway. The exact position of these sites and, if necessary, additional sites should be decided after considering aeronautical, meteorological and climatological factors such as long runways, swamps and other fog-prone areas. 4.3.2 Instrumented systems Note.— Since accuracy can vary from one instrument design to another, performance characteristics are to be checked before selecting an instrument for assessing runway visual range. The calibration of a forward-scatter meter has to be traceable and verifiable to a Transmissometer standard, the accuracy of which has been verified over the intended operational range. Guidance on the use of Transmissometer and forward-scatter meters in instrumented runway visual range systems is given in the Manual of Runway Visual Range Observing and Reporting Practices (Doc 9328). 4.3.2.1 Instrumented systems based on Transmissometer or forward-scatter meters shall be used to assess runway visual range on runways intended for Category II and III instrument approach and landing operations. 4.3.2.2 Instrumented systems based on Transmissometer or forward-scatter meters should be used to assess runway visual range on runways intended for Category I instrument approach and landing operations. 4.3.3 Display 4.3.3.1 Where runway visual range is determined by instrumented systems, one display or more, if required, shall be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units shall be related to the same sensors, and where separate sensors are required as specified in 4.3.1.2, the displays shall be clearly marked to identify the runway and section of runway monitored by each sensor. 4.3.3.2 Where runway visual range is determined by human observers, runway visual range should be reported to the appropriate local air traffic services units, whenever there is a change in the value to be reported in accordance with the reporting scale (except where the provisions of 3.2.2 a) or b) apply). The transmission of such reports should normally be completed within 15 seconds after the termination of the observation. Rev. 2, 8 November 2018 77 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 4.3.4 Averaging Where instrumented systems are used for the assessment of runway visual range, their output shall be updated at least every 60 seconds to permit the provision of current, representative values. The averaging period for runway visual range values shall be: a) 1 minute for local routine and special reports and for runway visual range displays in air traffic services units; and b) 10 minutes for METAR and SPECI, except that when the 10-minute period immediately preceding the observation includes a marked discontinuity in runway visual range values, only those values occurring after the discontinuity shall be used for obtaining mean values. Note.— A marked discontinuity occurs when there is an abrupt and sustained change in runway visual range, lasting at least 2 minutes, which reaches or passes through the values 800, 550, 300 and 175m. 4.3.5 Runway light intensity When instrumented systems are used for the assessment of runway visual range, computations should be made separately for each available runway. For local routine and special reports, the light intensity to be used for the computation should be: a) for a runway with the lights switched on and the light intensity of more than 3 per cent of the maximum light intensity available, the light intensity actually in use on that runway; b) for a runway with the lights switched on and the light intensity of 3 per cent or less of the maximum light intensity available, the optimum light intensity that would be appropriate for operational use in the prevailing conditions; and c) for a runway with lights switched off (or at the lowest setting pending the resumption of operations), the optimum light intensity that would be appropriate for operational use in the prevailing conditions. In METAR and SPECI, the runway visual range should be based on the maximum light intensity available on the runway. Note.— Guidance on the conversion of instrumented readings into runway visual range is given at Attachment D. 4.3.6 Reporting 4.3.6.1 In local routine and special reports and in METAR and SPECI, the runway visual range shall be reported in steps of 25 m when the runway visual range is less than 400 m; in steps of 50 m when it is between 400 m and 800 m; and in steps of 100 m when the runway visual range is more than 800 m. Any observed value which does not fit the reporting scale in use shall be rounded down to the nearest lower step in the scale. Rev. 2, 8 November 2018 78 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 4.3.6.2 Fifty meters should be considered the lower limit and 2000 meters the upper limit for runway visual range. Outside of these limits, local routine and special reports and METAR and SPECI should merely indicate that the runway visual range is less than 50 m or more than 2000 m. 4.3.6.3 In local routine reports, local special reports, METAR and SPECI: a) when runway visual range is above the maximum value that can be determined by the system in use, it shall be reported using the abbreviation “ABV” in local routine and special reports and the abbreviation “P” in METAR and SPECI, followed by the maximum value that can be determined by the system; and b) When the runway visual range is below the minimum value that can be determined by the system in use, it shall be reported using the abbreviation “BLW” in local routine and special reports and the abbreviation “M” in METAR and SPECI, followed by the minimum value that can be determined by the system. 4.3.6.4 In local routine and special reports: a) the units of measurement used shall be included; b) if runway visual range is observed from only one location along the runway, i.e. the touchdown zone, it shall be included without any indication of location; c) if the runway visual range is observed from more than one location along the runway, the value representative of the touchdown zone shall be reported first, followed by the values representative of the mid-point and stop-end and the locations for which these values are representative shall be indicated; and d) When there is more than one runway in use, the available runway visual range values for each runway shall be reported and the runways to which the values refer shall be indicated. 4.3.6.5 In METAR and SPECI: a) only the value representative of the touchdown zone should be reported and no indication of location on the runway should be included; and b) Where there is more than one runway available for landing, touchdown zone runway visual range values should be included for all such runways, up to a maximum of four, and the runways to which the values refer should be indicated. 4.3.6.6 In METAR and SPECI when instrumented systems are used for the assessment of runway visual range, the variations in runway visual range during the 10- minute period immediately preceding the observation should be included if the runway visual range values during the 10-minute period have shown a distinct tendency, such that the mean during the first 5 minutes varies by 100 m or more from the mean during the second 5 minutes of the period. When the variation Rev. 2, 8 November 2018 79 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 of the runway visual range values shows an upward or downward tendency, this should be indicated by the abbreviation “U” or “D”, respectively. In circumstances when actual fluctuations during the 10-minute period show no distinct tendency, this should be indicated using the abbreviation “N”. When indications of tendency are not available, no abbreviations should be included. 4.4 Present weather 4.4.1 Siting When instrumented systems are used for observing present weather phenomena listed under 4.4.2.3 and 4.4.2.4, representative information should be obtained by the use of sensors appropriately sited. 4.4.2 Reporting 4.4.2.1 In local routine and special reports, observed present weather phenomena shall be reported in terms of type and characteristics and qualified with respect to intensity, as appropriate. 4.4.2.2 In METAR and SPECI, observed present weather phenomena shall be reported in terms of type and characteristics and qualified with respect to intensity or proximity to the aerodrome, as appropriate. 4.4.2.3 In local routine and special reports and in METAR and SPECI, the following types of present weather phenomena should be reported, using their respective abbreviations and relevant criteria, as appropriate: a) Precipitation Drizzle DZ Rain RA Snow SN Snow grains SG Ice pellets PL Hail GR — Reported when diameter of largest hailstones is 5 mm or more. Small hail GS — Reported when diameter of largest hailstones is less than Rev. 2, 8 November 2018 80 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 5 mm; a) Obscurations (hydrometeors) Fog FG — Reported when visibility is less than 1000 m, except when qualified by “MI”, “BC”, “PR” or “VC” (see 4.4.2.6 and 4.4.2.8). Mist BR — Reported when visibility is at least 1000 m but not more than 5000 m; b) Obscurations (litho meteors) — The following should be used only when the obscuration consists predominantly of litho meteors and the visibility is 5000 m or less except “SA” when qualified by “DR” (see 4.4.2.6) and volcanic ash. Sand SA Dust (widespread) DU Haze HZ Smoke FU Volcanic ash VA c) Other phenomena Dust/sand whirls (dust devils) PO Squall SQ Funnel cloud (tornado or waterspout) FC Dust storm DS Sandstorm SS 5.1.1.2 In automated local routine reports, local special reports, METAR and SPECI, in addition to the precipitation types listed under 4.4.2.3 a), the abbreviation UP should be used for unidentified precipitation when the type of precipitation cannot be identified by the automatic observing system. Rev. 2, 8 November 2018 81 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 5.1.1.3 In local routine and special reports and in METAR and SPECI, the following characteristics of present weather phenomena, as necessary, shall be reported, using their respective abbreviations and relevant criteria, as appropriate: Thunderstorm TS — Used to report a thunderstorm with precipitation in accordance with the templates shown in Tables A3-1 and A3-2. When thunder is heard or lightning is detected at the aerodrome during the 10- minute period preceding the time of observation but no precipitation is observed at the aerodrome, the abbreviation “TS” should be used without qualification. Freezing FZ — Super cooled water droplets or precipitation, used with types of present weather phenomena in accordance with the templates shown in Tables A3-1 and A3-2. Note.— At aerodromes with human observers, lightning detection equipment may supplement human observations. For aerodromes with automatic observing systems, guidance on the use of lightning detection equipment intended for thunderstorm reporting is given in the Manual on Automatic Meteorological Observing Systems at Aerodromes (Doc 9837). 5.1.1.4 In local routine reports, local special reports, METAR and SPECI, the following characteristics of present weather phenomena, as necessary, should be reported, using their respective abbreviations and relevant criteria, as appropriate: Shower SH — Used to report showers in accordance with the templates shown in Tables A3-1 and A3-2. Showers observed in the vicinity of the aerodrome (see 4.4.2.8) should be reported as “VCSH” without qualification regarding type or intensity of precipitation. Blowing BL — Used in accordance with the templates shown in Tables A3-1 and A3-2 with types of present weather phenomena raised by the wind to a height of 2 m (6 ft) or more above the ground. Low drifting DR — Used in accordance with the templates shown in Tables A3-1 and A3-2 with types of present weather phenomena raised by the wind to less than 2 m (6 ft) above ground level. Rev. 2, 8 November 2018 82 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Shallow MI — Less than 2 m (6 ft) above ground level. Patches BC — Fog patches randomly covering the aerodrome. Partial PR — A substantial part of the aerodrome covered by fog while the remainder is clear. 5.1.1.5 In local routine reports, local special reports, METAR and SPECI, when showers (SH) referred to in 4.4.2.6 cannot be determined based upon a method that takes account of the presence of convective cloud, the precipitation shouldnot be characterized by SH. 5.1.1.6 In local routine reports, local special reports, METAR and SPECI, the relevant intensity or, as appropriate, the proximity to the aerodrome of the reported present weather phenomena should be indicated as follows: (local routine and special reports) (METAR and SPECI) Light FBL — Moderate MOD (no indication) Heavy HVY + Used with types of present weather phenomena in accordance with the templates shown in Tables A3-1 and A3-2. Light intensity should be indicated only for precipitation. Vicinity VC — Between approximately 8 and 16 km of the aerodrome reference point and used only in METAR and SPECI with present weather in accordance with the template shown in Table A3-2 when not reported under 4.4.2.5 and 4.4.2.6. 5.1.1.7 In local routine reports, local special reports, METAR and SPECI: a) one or more, up to a maximum of three, of the present weather abbreviations given in 4.4.2.3 and 4.4.2.4 shall be used, as necessary, together with an indication, where appropriate, of the characteristics given in 4.4.2.5 and 4.4.2.6 and intensity or proximity to the aerodrome given in 4.4.2.8, so as to convey a complete description of the present weather of significance to flight operations; b) the indication of intensity or proximity, as appropriate, shall be reported first followed respectively by the characteristics and the type of weather Rev. 2, 8 November 2018 83 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Phenomena; and c) Where two different types of weather are observed, they shall be reported in two separate groups, where the intensity or proximity indicator refers to the weather phenomenon which follows the indicator. However, different types of precipitation occurring at the time of observation shall be reported as one single group with the dominant type of precipitation reported first and preceded by only one intensity qualifier which refers to the intensity of the total precipitation. 5.1.1.8 In automated local routine reports, local special reports, METAR and SPECI, the present weather should be replaced by “//” when the present weather cannot be observed by the automatic observing system due to a temporary failure of the system/sensor. 4.5 Clouds 4.5.1 Siting When instrumented systems are used for the measurement of the cloud amount and the height of cloud base, representative observations should be obtained by the use of sensors appropriately sited. For local routine and special reports, in the case of aerodromes with precision approach runways, sensors for cloud amount and height of cloud base should be sited to give the best practicable indications of the cloud amount and height of cloud base at the threshold of the runway in use. For that purpose, a sensor should be installed at a distance of less than 1 200 m (4 000 ft) before the landing threshold. 4.5.2 Display When automated equipment is used for the measurement of the height of cloud base, height of cloud base display(s) should be located in the meteorological station with corresponding display(s) in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units should relate to the same sensor, and where separate sensors are required as specified in 4.5.1, the displays should clearly identify the area monitored by each sensor. 4.5.3 Reference level The height of cloud base shall be reported above aerodrome elevation. When a precision approach runway is in use which has a threshold elevation 15 m (50 ft) or more below the aerodrome elevation, local arrangements shall be made in order that the height of cloud bases reported to arriving aircraft shall refer to the threshold elevation. In the case of reports from offshore structures, the height of cloud base shall be given above mean sea level. 4.5.4 Reporting 4.5.4.1 In local routine reports, local special reports, METAR and SPECI, the height of cloud base shall be reported in steps of 30 m (100 ft) up to 3000 m (10000 ft). Rev. 2, 8 November 2018 84 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 4.5.4.2 At aerodromes where low-visibility procedures are established for approach and landing, as agreed between the meteorological authority and the appropriate ATS authority, in local routine and special reports the height of cloud base should be reported in steps of 15 m (50 ft) up to and including 90 m (300 ft) and in steps of 30 m (100 ft) between 90 m (300 ft) and 3 000 m (10000 ft), and the vertical visibility in steps of 15 m (50 ft) up to and including 90 m (300 ft) and in steps of 30 m (100 ft) between 90 m (300 ft) and 600 m (2000 ft). 4.5.4.3 In local routine reports, local special reports, METAR and SPECI: a) cloud amount should be reported using the abbreviations “FEW” (1 to 2 oktas), “SCT” (3 to 4 oktas), “BKN” (5 to 7 oktas) or “OVC” (8 oktas); b) cumulonimbus clouds and towering cumulus clouds should be indicated as “CB” and “TCU”, respectively; c) the vertical visibility should be reported in steps of 30 m (100 ft) up to 600 m (2000 ft); d) if there are no clouds of operational significance and no restriction on vertical visibility and the abbreviation “CAVOK” is not appropriate, the abbreviation “NSC” should be used; e) when several layers or masses of cloud of operational significance are observed, their amount and height of cloud base should be reported in increasing order of the height of cloud base, and in accordance with the following criteria: 1) the lowest layer or mass, regardless of amount to be reported as FEW, SCT, BKN or OVC as appropriate; 2) the next layer or mass, covering more than 2/8 to be reported as SCT, BKN or OVC as appropriate; 3) the next higher layer or mass, covering more than 4/8 to be reported as BKN or OVC as appropriate; and 4) cumulonimbus and/or towering cumulus clouds, whenever observed and not reported in 1) to 3); f) when the cloud base is diffuse or ragged or fluctuating rapidly, the minimum height of cloud base, or cloud fragments, should be reported; and g) When an individual layer (mass) of cloud is composed of cumulonimbus and towering cumulus clouds with a common cloud base, the type of cloud should be reported as cumulonimbus only. Note.— Towering cumulus indicates cumulus congestus clouds of great vertical extent. 4.5.4.4 Any observed value in 4.5.4.1, 4.5.4.2 and 4.5.4.3 c) which does not fit the reporting scale in use shall be rounded down to the nearest lower step in the scale. Rev. 2, 8 November 2018 85 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 4.5.4.5 In local routine and special reports: a) the units of measurement used for the height of cloud base and vertical visibility shall be indicated; and b) When there is more than one runway in use and the heights of cloud bases are observed by instruments for these runways, the available heights of cloud bases for each runway shall be reported and the runways to which the values refer shall be indicated. 4.5.4.6 In automated local routine reports, local special reports, METAR and SPECI: a) when the cloud type cannot be observed by the automatic observing system, the cloud type in each cloud group should be replaced by “///”; b) when no clouds are detected by the automatic observing system, it should be indicated by using the abbreviation “NCD”; and c) when cumulonimbus clouds or towering cumulus clouds are detected by the automatic observing system and the cloud amount and the height of cloud base cannot be observed, the cloud amount and/or the height of cloud base should be replaced by “///”, and d) The vertical visibility should be replaced by “///” when the sky is obscured and the value of the vertical visibility cannot be determined by the automatic observing system due to a temporary failure of the system/sensor. 4.6 Air temperature and dew-point temperature 4.6.1 Display When automated equipment is used for the measurement of air temperature and dew-point temperature, air temperature and dew-point temperature displays should be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units should relate to the same sensors. 4.6.2 Reporting 4.6.2.1 In local routine and special reports and in METAR and SPECI, the air temperature and the dew-point temperature shall be reported in steps of whole degrees Celsius. Any observed value which does not fit the reporting scale in use shall be rounded to the nearest whole degree Celsius, with observed values involving 0.5° rounded up to the next higher whole degree Celsius. 4.6.2.2 In local routine reports, local special reports, METAR and SPECI, a temperature below 0°C shall be identified. 4.7 Atmospheric pressure 4.7.1 Display Rev. 2, 8 November 2018 86 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 When automated equipment is used for the measurement of atmospheric pressure, QNH and, if required in accordance with 4.7.3.2 b), QFE displays relating to the barometer shall be located in the meteorological station with corresponding displays in the appropriate air traffic services units. When QFE values are displayed for more than one runway, as specified in 4.7.3.2 d), the displays shall be clearly marked to identify the runway to which the QFE value displayed refers. 4.7.2 Reference level The reference level for the computation of QFE should be the aerodrome elevation. For non-precision approach runways, the thresholds of which are 2 m (7 ft) or more below the aerodrome elevation, and for precision approach runways, the QFE, if required, should refer to the relevant threshold elevation. 4.7.3 Reporting 4.7.3.1 For local routine reports, local special reports, METAR and SPECI, QNH and QFE shall be computed in tenths of hector Pascals and reported therein in steps of whole hector Pascals, using four digits. Any observed value which does not fitthe reporting scale in use shall be rounded down to the nearest lower whole hector pascal. 4.7.3.2 In local routine and special reports: a) QNH shall be included; b) QFE shall be included if required by users or as agreed between the meteorological authority, the appropriate air traffic services authorities and the operators concerned, on a regular basis; c) the units of measurement used for QNH and QFE values shall be included; and d) if QFE values are required for more than one runway, the required QFE values for each runway shall be reported and the runways to which the values refer shall be indicated. 4.7.3.3 In METAR and SPECI, only QNH values shall be included. 4.8 Supplementary information 4.8.1 Reporting 4.8.1.1 In local routine reports, local special reports, METAR and SPECI, the following recent weather phenomena, i.e. weather phenomena observed at the aerodrome during the period since the last issued routine report or last hour, whichever is the shorter, but not at the time of observation, should be reported, up to a maximum of three groups, in accordance with the templates shown in Tables A3-1 and A3-2, in the supplementary information: Rev. 2, 8 November 2018 87 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 - freezing precipitation - moderate or heavy precipitation (including showers thereof) - blowing snow - dust storm, sandstorm - thunderstorm - funnel cloud (tornado or water spout) - volcanic ash Note.— The meteorological authority, in consultation with users, may agree not to provide recent weather information where SPECI are issued. 4.8.1.2 In local routine and special reports, the following significant meteorological conditions, or combinations thereof, should be reported in supplementary information: --cumulonimbus clouds CB --thunderstorm TS --moderate or severe turbulence MOD TURB, SEV TURB --wind shear WS --hail GR --severe squall line SEV SQL --moderate or severe icing MOD ICE, SEV ICE -- freezing precipitation FZDZ, FZRA -- severe mountain waves SEV MTW --dust storm, sandstorm DS, SS -- blowing snow BLSN -- funnel cloud (tornado or water spout) FC The location of the condition should be indicated. Where necessary, additional information should be included using abbreviated plain language. 4.8.1.3 In automated local routine reports, local special reports, METAR and SPECI, in addition to the recent weather phenomena listed under 4.8.1.1, recent unknown precipitation should be reported in accordance with the template shown in Table A3-2 when the type of precipitation cannot be identified by the automatic observing system. Note.— The meteorological authority, in consultation with users, may agree not to provide recent weather information where SPECI are issued. 4.8.1.4 In METAR and SPECI, where local circumstances so warrant, information on Rev. 2, 8 November 2018 88 thCIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 wind shear should be added. Note – The local circumstances referred to in 4.8.1.4 include, but are not necessarily limited to, wind shear of a non-transitory nature such as might be associated with low level temperature inversions or local topography. 4.8.1.5 Recommendation.— Until 3 November 2021, In METAR and SPECI, the following information should be included in the supplementary information, in accordance with regional air navigationagreement: a) information on sea-surface temperature and the state of the sea from aeronautical meteorological stations established on offshore structures in support of helicopter operations; and b) information on the state of the runway provided by the appropriate airport authority. Note 1.— The state of the sea is specified in the Manual on Codes (WMO- No.306), Volume I.1, Part A — Alphanumeric Codes, Code Table 3700. Note 2.— The state of the runway is specified in Manual on Codes (WMO- No.306), Volume I.1, Part A — Alphanumeric Codes, Code Tables 0366, 0519, 0919 and 1079. 4.8.1.6 Recommendation.— As of 4 November 2021, in METAR and SPECI, information on sea-surface temperature, and the state of the sea or the significant wave height, from aeronautical meteorological stations established on offshore structures in support of helicopter operations should be included in the supplementary information, in accordance with regional air navigation agreement. Note.— The state of the sea is specified in the Manual on Codes (WMO-No. 306), Volume I.1, Part A — AlphanumericCodes, Code Table 3700. Rev. 2, 8 th November 2018 89CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Table A3-1. Template for the local routine (MET REPORT) and local special (SPECIAL)reports Key: M = inclusion mandatory, part of every message; C = inclusion conditional, dependent on meteorological conditions; O = inclusion optional. Note 1.— The ranges and resolutions for the numerical elements included in the localroutine and special reports are shown in Table A3-4 of this appendix. Note 2.— The explanations for the abbreviations can be found in the Procedures for AirNavigation Services — ICAO Abbreviations and Codes (PANS-ABC, Doc 8400). Element as specified in Detailed content Template(s) Examples Para 4 Identification of the Type of report MET REPORT or SPECIAL MET REPORT type of report (M) SPECIAL Location indicator ICAO location indicator nnnn YUDO1 (M) (M) Time of the Day and actual time of the nnnnnnZ 221630Z observation observation in UTC (M) Identification of an Automated report AUTO AUTO automated report identifier (C) (C) Surface wind (M) Name of the element (M) WIND WIND 240/4MPS (WIND Runway (O)2 RWY nn[L] or RWY nn[C] or RWY nn[R] 240/8KT) Runway section (O)3 TDZ WIND RWY 18 TDZ Wind direction (M) nnn/ VRB BTN nnn/ AND nnn/ C 190/6MPS (WIND RWY or A 18 TDZ 190/12KT) VRB L M WIND VRB1MPS WIND CALM (WIND VRB2KT) Wind speed (M) [ABV]n[n][n]MPS (or [ABV]n[n]KT) WIND VRB BTN 350/ AND 050/1MPS (WIND VRB BTN Significant speed MAX[ABV]nn[n] MNMn[n] 350/ AND 050/2KT) variations (C)4 WIND Significant directional VRB BTN 270/ABV49MP variations (C)5 nnn/ AND — S (WIND nnn/ 270/ABV99KT) Runway section (O)3 MID WIND 120/3MPS MAX9 MNM2 (WIND 120/6KT Wind direction (O)3 nnn/ VRB BTN nnn/ AND nnn/ C MAX18 MNM4) or A VRB L WIND 020/5MPS VRB BTN M Wind speed (O)3 [ABV]n[n][n]MPS (or [ABV]n[n]KT) 350/ AND 070/ (WIND 020/10KT VRB BTN 350/ AND Significant speed MAX[ABV]nn[n] MNMn[n] 070/) variations (C)4 Significant directional VRB BTN WIND RWY 14R MID variations (C)5 nnn/ AND — 140/6MPS (WIND RWY nnn/ 14R MID 140/12KT) Runway section (O)3 END WIND RWY 27 TDZ Wind direction (O)3 nnn/ VRB BTN nnn/ AND nnn/ C 240/8MPS MAX14 or A MNM5 END VRB L 250/7MPS (WIND Rev. 2, 8 th November 2018 90CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Wind speed (O)3 [ABV]n[n][n]MPS (or [ABV]n[n]KT) M RWY 27 TDZ 240/16KT MAX28 MNM10 END 250/14KT) Element as specified in Detailed content Template(s) Examples Para 4 Significant MAX[ABV]nn[n] MNMn[n] speed variations (C)4 Significant VRB BTN directional nnn/ AND nnn/ — variations (C)5 Visibility (M) Name of the VIS C element (M) A VIS 350M CAVOK VIS 7KM V Runway (O)2 RWY nn[L] or RWY nn[C] or O VIS 10KM RWY nn[R] K Runway section (O)3 TDZ VIS RWY 09 TDZ 800M END 1200M Visibility (M) nn[n][n]M or n[n]KM Runway section (O)3 MID VIS RWY 18C TDZ 6KM RWY 27 TDZ 4000M Visibility (O)3 nn[n][n]M or n[n]KM Runway section (O)3 END Visibility (O)3 nn[n][n]M or n[n]KM Runway visual Name of the RVR RVR RWY 32 400M RVR range (C)6 element (M) RWY 20 1600M Runway (C)7 RWY nn[L] or RWY nn[C] or RVR RWY 10L BLW 50M RVR RWY nn[R] RWY 14 ABV 2000M RVR RWY Runway section (C)8 TDZ 1 A0 B VB L 1W 20 1 05 M0 M RVR RWY 12 RVR (M) [ABV or BLW] nn[n][n]M RVR RWY 12 TDZ 1100M MID ABV 1400M RVR RWY 16 TDZ 600M MID 500M END 400M Runway section (C)8 MID RVR RWY 26 500M RWY 20 800M RVR (C)8 [ABV or BLW] nn[n][n]M Runway section (C)8 END RVR (C)8 [ABV or BLW] nn[n][n]M Present weather Intensity of FBL or MOD (C)9, 10 present weather or HVY — (C)9 Characteristics and DZ or IC or MOD RA type of present RA or FG or HVY TSRA weather (C)9,11 SN or BR or HVY DZ SG or SA or FBL SN PL or DU or HZ DS or HZ or FG SS or FU or VA FZDZ or VA or MIFG FZUP12 or SQ or HVY TSRASN FC13 or PO or FBL SNRA FZRA or FC or SHGR or TS or FBL DZ FG SHGS or BCFG HVY SHSN BLSN SHRA or or SHSN or BLDU or HVY TSUP SHUP12 or BLSA or TSGR or BLSN or // TSGS or DRDU or TSRA or DRSA or TSSN or DRSN or TSUP12 or FZFG or UP12 MIFG or PRFG Rev. 2, 8 th November 2018 91CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Element as specified in Para 4 Detailed content Template(s) Examples Height of cloud n[n][n][n] [VER VIS CLD /// CB 400M (CLD /// CB base or the value M (or n[n][n]M( 1200FT) CLD NCD of vertical visibility n[n][n][n]F or VER (C)9 T) or VIS /// n[n][n][n]F M T)] (or or ///FT)12 VER VIS ///M (or VER VIS ///FT)12 Air temperature (M) Name of the element (M) T T17 Air temperature (M) [MS]nn TMS0 8 Dew-point Name of the element (M) DP DP15 temperature Dew-point temperature [MS]nn DPMS (M) (M) 18 Pressure values Name of the element (M) QNH QNH (M) QNH (M) nnnnHPA 0995HPA QNH Name of the element (O) QFE 1009HPA QFE (O) [RWY nn[L] or RWY nn[C] or RWY nn[R]] nnnnHPA [RWY nn[L] or RWY nn[C] or QNH 1022HPA QFE 1001HPA RWY nn[R] nnnnHPA] QNH 0987HPA QFE RWY 18 0956HPA RWY 24 0955HPA Supplement Significant CB or TS or MOD TURB or SEV TURB or WS or FC IN APCH ary meteorological GR or WS IN APCH 60M-WIND information phenomena (C)9 SEV SQL or MOD ICE or SEV ICE or FZDZ or 360/13MPS WS RWY 12 (C)9 FZRA or SEV MTW or SS or DS or BLSN or FC15 Location of IN APCH [n[n][n][n]M-WIND nnn/n[n]MPS] or REFZRA the IN CLIMB-OUT [n[n][n][n]M-WIND nnn/n[n]MPS] CB IN CLIMB-OUT RETSRA phenomena (IN APCH [n[n][n][n]FT-WIND nnn/n[n]KT] or (C)9 IN CLIMB-OUT [n[n][n][n]FT-WIND nnn/n[n]KT]) or RWY nn[L] or RWY nn[C] or RWY nn[R] Recent weather (C)9, 10 REFZDZ or REFZRA or REDZ or RE[SH]RA or RE[SH]SN or RESG or RESHGR or RESHGS or REBLSN or RESS or REDS or RETSRA or RETSSN or RETSGR or RETSGS or REFC or REPL or REUP12 or REFZUP12 or RETSUP12 or RESHUP12 or REVA or RETS Trend forecast Name of the element (M) TREND TREND NOSIG TREND BECMG FEW (O)16 600M (TREND BECMG FEW 2000FT) Change indicator (M)17 NOSIG BECMG or TEMPO TREND TEMPO 250/18 MPS Period of change (C)9 FMnnnn and/or TLnnnn or ATnnnn MAX25 (TREND TEMPO Wind (C)9 nnn/[ABV]n[n][n]MPS [MAX[ABV]nn[n]] 250/36KT MAX50) (or nnn/[ABV]n[n]KT [MAX[ABV]nn]) TREND BECMG AT1800 VIS Visibility (C)9 VIS n[n][n][n]M or C 10KM NSW TREND BECMG VIS n[n]KM A Rev. 2, 8 th November 2018 92CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Weather FBL — NSW V TL1700 VIS 800M FG TREND phenomenon: or O BECMG FM1030 TL1130 CAVOK intensity (C)9 MOD K or TREND TEMPO TL1200 VIS 600M HVY BECMG AT1230 VIS 8KM NSW CLD NSC Element as specified in Para 4 Detailed content Template(s) Examples Visibility (C)9 VIS nn[n][n]M C or A TREND TEMPO FM0300 TL0430 MOD FZRA VIS n[n]KM V TREND BECMG FM1900 VIS 500M HVY SNRA O TREND BECMG FM1100 MOD SN TEMPO K FM1130 BLSN Weather FBL or — NSW TREND BECMG AT1130 CLD OVC 300M phenomenon: MOD or (TREND BECMG AT 1130 CLD OVC 1000FT) intensity (C)9 HVY Weather DZ or RA IC or FG or TREND TEMPO TL150 HVY SHRA CLD BKN CB phenomenon: or SN or BR or SA or 360M (TREND TEMPO TL1530 HVY SHRA CLD characteristics SG or PL DU or HZ or BKN CB 1200FT) and type (C)9, 10, or DS or FU or VA or 11 SS or SQ or PO or FZDZ or FC or TS or FZRA or BCFG or SHGR or BLDU or SHGS or BLSA or SHRA or BLSN or SHSN or DRDU or TSGR or DRSA or TSGS or DRSN or TSRA or FZFG or TSSN MIFG or PRFG Name of the element CLD (C)9 Cloud amount and FEW or OBSC NSC vertical visibility (C)9 SCT or BKN or OVC Cloud type (C)9 CB or — TCU Height of cloud n[n][n][n] [VER VIS base or the M (or n[n][n]M n[n][n][n] (or VER value of vertical visibility (C)9 FT) V n[I nS ] [n][n] FT)] Notes.— 1. Fictitious location. 2. Optional values for one or more runways. 3. Optional values for one or more sections of the runway. 4. To be included in accordance with 4.1.5.2 c). 5. To be included in accordance with 4.1.5.2 b) 1). 6. To be included if visibility or runway visual range < 1 500 m. 7. To be included in accordance with 4.3.6.4 d). 8. To be included in accordance with 4.3.6.4 c). Rev. 2, 8 th November 2018 93CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 9. To be included whenever applicable. 10. One or more, up to a maximum of three groups, in accordance with 4.4.2.9 a), 4.8.1.1 and Appendix 5, 2.2.4.3. 11. Precipitation types listed under 4.4.2.3 a) may be combined in accordance with 4.4.2.9 c) and Appendix 5, 2.2.4.1. Only moderate or heavy precipitation to be indicated in trend forecasts in accordance with Appendix 5, 2.2.4.1. 12. For automated reportsonly 13. .Heavy used to indicate tornado or waterspout; moderate used to indicate funnel cloud not reaching the ground. 14. Up to four cloud layers in accordance with 4.5.4.3 e). 15. Abbreviated plain language may be used in accordance with 4.8.1.2. 16. To be included in accordance with Para 6, 6.3.2. 17. Number of change indicators to be kept to a minimum in accordance with Appendix 5, 2.2.1, normally not exceeding three groups Table A3-2.Template for METAR and SPECI (Applicable as of 4 November 2021) Key: M = inclusion mandatory, part of every message; C = inclusion conditional, dependent on meteorological conditions or method of observation; O = inclusion optional. Note 1.— The ranges and resolutions for the numerical elements included in METAR and SPECI areshown in Table A3-5 of this appendix. Note 2.— The explanations for the abbreviations can be found in the PANS-ABC (Doc 8400). Element as specifiedin Chapter 4 Detailed content Template(s) Examples Identification of the Type of report (M) METAR, METAR COR, SPECI or SPECI COR METAR METAR type of report (M) CORSPECI Location indicator (M) ICAO location indicator (M) nnnn YUDO1 Time of the observation Day and actual time of the nnnnnnZ 221630Z (M) observation in UTC (M) Identification of an Automated or missing report AUTO or NIL AUTO automated or missing identifier (C) NIL report (C)2 END OF METAR IF THE REPORT IS MISSING. Surface wind (M) Wind direction (M) Nnn or III12 VRB 24004MPS VRB01MPS III10MPS Wind speed (M) [P]nn[n] or II12 (24008KT) (VRB02KT) 240IIKT 19006MPS IIIIKT (19012KT) 00000MPS (00000KT) 140P49MPS (140P99KT) Significant speed variations (C)3 G[P]nn[n] 12003G09MPS Rev. 2, 8 th November 2018 94CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Element as specifiedin Chapter 4 Detailed content Template(s) Examples Units of measurement (M) MPS (or KT) (12006G18KT) 24008G14MPS (24016G28KT) Significant directional nnnVnnn — 02005MPS 350V070 variations (C)4 (02010KT 350V070) Visibility (M) Prevailing or minimum Nnnn or IIII12 C 0350 IIII CAVOK visibility (M)5 A 7000 9999 V 0800 O Minimum visibility and nnnn[N] or nnnn[NE] or nnnn[E] or nnnn[SE] or 2000 1200NW K direction of the minimum nnnn[S] or nnnn[SW] or nnnn[W] or nnnn[NW] 6000 2800E visibility (C)6 6000 2800 Runway visual range Name of the element (M) R R32/0400 (C)7 R12R/1700 Runway (M) nn[L]/or nn[C]/or nn[R]/ R10/M0050 R14L/P2000 Runway visual range (M) [P or M]nnnn or IIII12 R16L/0650 R16C/0500 R16LIIII R10IIII R16R/0450 R17L/0450 Runway visual range past U, D or N R12/1100U tendency (C)8 R26/0550N R20/0800D R12/0700 Present weather Intensity or proximity of present – or + — VC (C)2, 9 weather (C)10 Characteristics and type of DZ or RA or FG or BR or FG or PO or RA HZ VCFG present weather (M)11 SN or SG or SA or DU or FC or DS or +TSRA FG VCSH PL or DS or HZ or FU or SS or TS or +DZ VA VCTS SS or VA or SQ or SH or BLSN or –SN MIFG VCBLSA FZDZ or PO or TS or BLSA or FZRA or BCFG or BLDU or VA +TSRASN FZUP12 or BLDU or –SNRA FC13 or BLSA or SHGR or BLSN or DZ FG SHGS or DRDU or +SHSN BLSN SHRA or DRSA or UP SHSN or DRSN or FZUP SHUP12 or FZFG or TSUP FZUP TSGR or MIFG or TSGS or PRFG or //12 // TSRA or TSSN or TSUP12 or UP12 Cloud (M)14 Cloud amount and FEWnnn or VVnnn or NSC or FEW015 VV005 height of cloud base or SCTnnn or VV///12 NCD12 OVC030 VV/// NSC vertical visibility (M) BKNnnn or OVCnnn or SCT010 OVC020 FEW///12 or SCT///12 or BKN/// ///015 BKN///12 or OVC///12 or ///nnn12 or //////12 Rev. 2, 8 th November 2018 95CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Element as specifiedin Chapter 4 Detailed content Template(s) Examples Cloud type (C)2 CB or — BKN009TCU NCD TCU or ///12 SCT008 BKN025CB BKN025/// III///CB ///////// BKN///TCU Air and dew-point Air and dew-point temperature [M]nn/[M]nn or ///[M]nn12 or [M]nn///12 or /////12 17/10 ///10 17/// ///// temperature (M) (M) 02/M08 M01/M10 Pressure values (M) Name of the element (M) Q Q0995 Q1009 QNH (M) nnnn or IIII12 Q1022 QIIII Q0987 Supplementary Recent weather (C)2, 9 RERASN or REFZDZ or REFZRA or REDZ or RE[SH]RA or REFZRA information (C) RE[SH]SN or RESG or RESHGR or RESHGS or REBLSN or RETSRA RESS or REDS or RETSRA or RETSSN or RETSGR or RETSGS or RETS or REFC or REVA or REPL or REUP12 or REFZUP12 or RETSUP12 or RESHUP12 or REII12 Wind shear (C)2 WS Rnn[L] or WS Rnn[C] or WS Rnn[R] or WS ALL RWY WS R03 WS ALL RWY WS R18C Sea-surface temperature and W[M]nn/Sn or W///Sn or W[M]nn/S/ or W[M]nn/Hn[n][n] or W15/S2 state of the sea or significant W///Hn[n][n] or W[M]nn/H/// W12/H75 wave height (C)15 W///S3 WM01/S/ W///H104 W17/H/// W///H/// W///S/ Trend forecast (O)17 Change indicator (M)17 NOSIG BECMG or TEMPO NOSIG BECMG FEW020 Period of change (C)2 FMnnnn and/or TEMPO 25018G25MPS(TEMPO TLnnnn 25036G50KT) or ATnnnn BECMG FM1030 TL1130 CAVOK Wind (C)2 nnn[P]nn[n][G[P]nn[n]]MPS (or nnn[P]nn[G[P]nn]KT) BECMG TL1700 0800 FG Prevailing visibility (C)2 nnnn C A BECMG AT1800 9000 NSW Weather phenomenon:intensity – or + — N S V O (C)10 W K BECMG FM1900 0500 +SNRA Weather phenomenon: DZ or RA or FG or BR or BECMG FM1100 SN TEMPO FM1130 BLSN characteristics and type SN or SG or SA or DU or (C)2, 9, 11 PL or DS or HZ or FU or TEMPO FM0330 TL0430 FZRA SS or VA or SQ or TEMPO TL1200 0600 BECMG AT1200 8000 FZDZ or PO or FC or NSW NSC FZRA or TS or BCFG SHGR or or BLDU or BECMG AT1130 OVC010 SHGS or BLSA or SHRA or BLSN or TEMPO TL1530 +SHRA BKN012CB SHSN or DRDU or TSGR or DRSA or TSGS or DRSN or TSRA or FZFG or TSSN MIFG or PRFG Cloud amount and height of cloud FEWnnn or VVnnn or N S base or vertical visibility (C)2, 14 SCTnnn or VV/// C BKNnnn or OVCnnn Rev. 2, 8 th November 2018 96CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Element as specifiedin Chapter 4 Detailed content Template(s) Examples Cloud type (C)2,14 CB or TCU — Notes.— 1. Fictitious location. 2. To be included whenever applicable. 3. To be included in accordance with 4.1.5.2 c). 4. To be included in accordance with 4.1.5.2 b) 1). 5. To be included in accordance with 4.2.4.4 b). 6. To be included in accordance with 4.2.4.4 a). 7. To be included if visibility or runway visual range < 1 500 m; for up to a maximum of four runways in accordance with 4.3.6.5 b). 8. To be included in accordance with 4.3.6.6. 9. One or more, up to a maximum of three groups, in accordance with 4.4.2.9 a), 4.8.1.1 and Appendix 5, 2.2.4.1. 10. To be included whenever applicable; no qualifier for moderate intensity in accordance with 4.4.2.8. 11. Precipitation types listed under 4.4.2.3 a) may be combined in accordance with 4.4.2.9 c) and Appendix 5, 2.2.4.1. Only moderate or heavy precipitation to be indicated in trend forecasts in accordance with Appendix 5, 2.2.4.1. 12. When a meteorological element is temporarily missing, or its value considered temporarily as incorrect, it is replaced by “/” for each digit of the abbreviation of the text message and indicated as missing for its IWXXM version. 13. Heavy used to indicate tornado or waterspout; moderate (no qualifier) to indicate funnel cloud not reaching the ground. 14. Up to four cloud layers in accordance with 4.5.4.3 e). 15. To be included in accordance with 4.8.1.5 a). 16. To be included in accordance with Chapter 6, 6.3.2. 17. Number of change indicators to be kept to a minimum in accordance with Appendix 5, 2.2.1, normally not exceeding three . . . Table A3-3: Use of change indicators in trend forecasts Change Time indicator and Meaning indicator period NOSIG — no significant changes are forecast BECMG FMn1n1n1n1 TLn2n2n2n2 the change is forecast commence at n1n1n1n1 UTC and be completed by n2n2n2n2 UTC to TLnnnn commence at the beginning of the trend forecast period and be completed by nnnn UTC FMnnnn commence at nnnn UTC and be completed by the end of the trend forecast period ATnnnn occur at nnnn UTC (specified time) — a) commence at the beginning of the trend forecast period and be completed by the end of the trend forecast period; or b) the time is uncertain TEMPO FMn1n1n1n1 TLn2n2n2n2 temporary commence at n1n1n1n1 UTC and cease by n2n2n2n2 UTC fluctuation s are forecast to TLnnnn commence at the beginning of the trend forecast period and cease by nnnn UTC FMnnnn commence at nnnn UTC and cease by the end of the trend forecast period — commence at the beginning of the trend forecast period and cease by the end of the trend forecast period Rev. 2, 8 th November 2018 97CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Table A3-4: Ranges and resolutions for the numerical elements included in local reports Element as specified in Para 4 Range Resolution Runway: (no units) 01 – 36 1 Wind direction: °true 010 – 360 10 Wind speed: MPS 1 – 99* 1 KT 1 – 199* 1 Visibility: M 0 – 750 50 M 800 – 4 900 100 KM 5 – 9 1 KM 10 – 0 (fixed value: 10 KM) RVR: M 0 – 375 25 M 400 – 750 50 M 800 – 2000 100 Vertical visibility: M 0 – 75** 15 M 90 – 600 30 FT 0 – 250** 50 FT 300 – 2000 100 Clouds: height of cloud base: M 0 – 75** 15 M 90 – 3 000 30 FT 0 – 250** 50 FT 300 – 10000 100 Air temperature; °C –80 – +60 1 Dew-point temperature: QNH; QFE: hPa 0500 – 1 100 1 * There is no aeronautical requirement to report surface wind speeds of 50 m/s (100 kt) or more; however, provision has been made for reporting wind speeds up to 99 m/s (199 kt) for non-aeronautical purposes, as necessary. ** Under circumstances as specified in 4.5.4.2; otherwise a resolution of 30 m (100 ft) is to be used. Table A3-5: Ranges and resolutions for the numerical elements included in METAR And SPECI Element as specified in Para 4 Range Resolution Runway: (no units) 01 – 36 1 Wind direction: °true 000 – 360 10 Wind speed: MPS 00 – 99* 1 KT 00 – 199* 1 Visibility: M 0000 – 0750 50 M 0800 – 4 900 100 M 5 000 – 9 000 1 000 M 10 000 – 0 (fixed value: 9 999) RVR: M 0000 – 0375 25 M 0400 – 0750 50 M 0800 – 2 000 100 Vertical visibility: 30’s M (100’s 000 – 020 1 FT) Clouds: height of 30’s M (100’s 000 – 100 1 cloudbase: FT) Rev. 2, 8 th November 2018 98CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Air temperature; Dew-point temperature: °C –80 – +60 1 QNH: hPa 0850 – 1 100 1 Sea-surface temperature: °C –10 – +40 1 State of the sea: (no units) 0 – 9 1 Significant wave height: M 0 - 999 0.1 State of the runway Runway designator: (no units) 01 – 36; 88; 99 1 [Until 3 November 2021] Runway deposits: (no units) 0 – 9 1 Extent of runway (no units) 1; 2; 5; 9 — contamination: Depth of deposit: (no units) 00 – 90; 92 – 99 1 Friction coefficient/braking (no units) 00 – 95; 99 1 action: * There is no aeronautical requirement to report surface wind speeds of 50 m/s (100 kt) or more; however, provision has been made for reporting wind speeds up to 99 m/s (199 kt) for non-aeronautical purposes, as necessary. Example A3-1: Routine report a) Local routine report (same location and weather conditions as METAR): MET REPORT YUDO 221630Z WIND 240/4MPS VIS 600M RVR RWY 12 TDZ 1000M MOD DZ FG CLD SCT 300M OVC 600M T17 DP16 QNH 1018HPA TREND BECMG TL1700 VIS 800M FG BECMG AT1800 VIS 10KM NSW b) METAR for YUDO (Donlon/International)*: METAR YUDO 221630Z 24004MPS 0600 R12/1000U DZ FG SCT010 OVC020 17/16 Q1018 BECMG TL1700 0800 FG BECMG AT1800 9999 NSW Meaning of both reports: Routine report for Donlon/International* issued on the 22nd of the month at 1630 UTC; surface wind direction 240 degrees; wind speed 4 metres per second; visibility (along the runway(s) in the local routine report; prevailing visibility in METAR) 600 metres; runway visual range representative of the touchdown zone for runway 12 is 1 000 metres and the runway visual range values have shown an upward tendency during previous 10 minutes (RVR tendency to be included in METAR only); and moderate drizzle and fog; scattered cloud at 300 metres; overcast at 600 metres; air temperature 17 degrees Celsius; dew-point temperature 16 degrees Celsius; QNH 1 018 hectopascals; trend during next 2 hours, visibility (along the runway(s) in the local routine report; prevailing visibility in METAR) becoming 800 metres in fog by 1700 UTC; at 1800 UTC visibility (along the runway(s) in the local routine report; prevailing visibility in METAR) becoming 10 kilometres or more and nil significant weather. * Fictitious location Note.— In this example, the primary units “metre per second” and “metre” were used for wind speed and height of cloud base, respectively. However, in accordance with Annex 5, the corresponding non-SI alternative units “knot” and “foot” may be used instead. Rev. 2, 8 th November 2018 99CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Example A3-2: Special report a) Local special report (same location and weather conditions as SPECI): SPECIAL YUDO 151115Z WIND 050/25KT MAX37 MNM10 VIS 1200M RVR RWY 05 ABV 1800M HVY TSRA CLD BKN CB 500FT T25 DP22 QNH 1018 HPA TREND TEMPO TL1200 VIS 600M BECMG AT1200 VIS 8KM NSW NSC b) SPECI for YUDO (Donlon/International)*: SPECI YUDO 151115Z 05025G37KT 3000 1200NE+TSRA BKN005CB 25/22 Q1008 TEMPO TL1200 0600 BECMG AT1200 8000 NSW NSC Meaning of both reports: Special report for Donlon/International* issued on the 15th of the month at 1115 UTC; surface wind direction 050 degrees; wind speed 25 knots gusting between 10 and 37 knots (minimum wind speed not to be included in SPECI) visibility 1 200 meres (along the runway(s) in the local special report); prevailing visibility 3 000 meters (in SPECI) with minimum visibility 1 200 meres to north east (directional variations to be included in SPECI only); RVR above 1 800 meters on runway 05 (RVR not required in SPECI with prevailing visibility of 3 000 meters); thunderstorm with heavy rain; broken cumulonimbus cloud at 500 feet; air temperature 25degrees Celsius; dew-point temperature 22 degrees Celsius; QNH 1 018 hecto pascals; trend during next 2 hours, visibility (along the runway(s) in the local special report; prevailing visibility in SPECI) temporarily 600 meres from 1115 to 1200, becoming at 1200 UTC visibility (along the runway(s) in the local special report; prevailing visibility in SPECI) 8 kilometers, thunderstorm ceases and nil significant weather and nil significant cloud. * Fictitious location Note.— In this example, the non-SI alternative units “knot” and “foot” were used for wind speed and height of cloud base, respectively. However, in accordance with Annex 5, the corresponding primary units “meres per second” and “meter” may be used instead. Rev. 2, 8 th November 2018 100CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 APPENDIX 4. TECHNICAL SPECIFICATIONS RELATED TO AIRCRAFT OBSERVATIONS AND REPORTS (See Para 5 of this CAR) 1 Contents of Air-Reports 1.1 Routine air-reports by air-ground data link 1.1.1 When air-ground data link is used and automatic dependent surveillance (ADS- c) or SSR Mode S is being applied, the elements contained in routine air-reports shall be: Message type designator Aircraft identification Data block 1 Latitude Longitude Level Time Data block 2 Wind direction Wind speed Wind quality flag Air temperature Turbulence (if available) Humidity (if available) Note.— When ADS-C or SSR Mode S is being applied, the requirements of routine air-reports may be met by the combination of the basic ADS-C/SSR Mode S data block (data block 1) and the meteorological information data block (data block 2), available from ADS-C or SSR Mode S reports. The ADS-C message format is specified in the PANS-ATM (Doc 4444), 4.11.4 and Para 13 and the SSR Mode S message format is specified in Annex 10, Volume III, Part I, Para 5. 1.1.2 When air-ground data link is used while ADS-C and SSR Mode S are not being applied, the elements contained in routine reports shall be: Message type designator Section 1 (Position information) Aircraft identification Position or latitude and longitude Time Flight level or altitude Next position and time over Ensuing significant point Rev. 2, 8 th November 2018 101CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Section 2 (Operational information) Estimated time of arrival Endurance Section 3 (Meteorological information) Air temperature Wind direction Wind speed Turbulence Aircraft icing Humidity (if available) Note.— When air-ground data link is used while ADS-C and SSR Mode S are not being applied, the requirements of routine air-reports may be met by the controller-pilot data link communication (CPDLC) application entitled “Position report”. The details of this data link application are specified in the Manual of Air Traffic Services Data Link Applications (Doc 9694) and in Annex 10, Volume III, Part I. 1.2 Special air-reports by air-ground data link When air-ground data link is used, the elements contained in special air-reports shall be: Message type designator Aircraft identification Data block 1 Latitude Longitude Level Time Data block 2 Wind direction Wind speed Wind quality flag Air temperature Turbulence (if available) Humidity (if available) Data block 3 Condition prompting the issuance of a special air-report (one condition to be selected from the list presented in Table A4-1). Note 1. — The requirements of special air-reports may be met by the data link flight information service (D-FIS) application entitled “Special air-report service”. The details of this data link application are specified in Doc 9694. Note 2. — In the case of a special air-report of pre-eruption volcanic activity, Rev. 2, 8 th November 2018 102CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Volcanic eruption or volcanic ash cloud, additional requirements are indicated in 4.2. 1.3 Special air-reports by voice communications When voice communications are used, the elements contained in special air- reports shall be: Message type designator Section 1 (Position information) Aircraft identification Position or latitude and longitude Time Level or range of levels Section 3 (Meteorological information) Condition prompting the issuance of a special air-report, to be selected from the list presented in Table A4-1. Note 1. — Air-reports are considered routine by default. The message type designator for special air-reports is specified in the PANS-ATM (Doc 4444), Appendix 1. Note 2. — In the case of a special air-report of pre-eruption volcanic activity, volcanic eruption or volcanic ash cloud, additional requirements are indicated in 4.2. 2 Criteria for Reporting 2.1 General When air-ground data link is used, the wind direction, wind speed, wind quality flag, air temperature, turbulence and humidity included in air-reports shall be reported in accordance with the following criteria. 2.2 Wind direction The wind direction shall be reported in terms degrees true, rounded to the nearest whole degree. 2.3 Wind speed The wind speed shall be reported in metres per second or knots, rounded to the nearest 1 m/s (1 knot). The units of measurement used for the wind speed shall be indicated. 2.4 Wind quality flag The wind quality flag shall be reported as 0 when the roll angle is less than 5 degrees and as 1 when the roll angle is 5 degrees or more. Rev. 2, 8 th November 2018 103CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 2.5 Air temperature The air temperature shall be reported to the nearest tenth of a degree Celsius. 2.6 Turbulence The turbulence shall be reported in terms of the cube root of the eddy dissipation rate (EDR). Note.— The EDR is an aircraft-independent measure of turbulence. However, the relationship between the EDR value and the perception of turbulence is a function of aircraft type, and the mass, altitude, configuration and airspeed of the aircraft. The EDR values given below describe the severity levels for a medium-sized transport aircraft under typical en-route conditions (i.e. altitude, airspeed and weight). 2.6.1 Routine air-reports The turbulence shall be reported during the en-route phase of the flight and shall refer to the 15-minute period immediately preceding the observation. Both the average and peak value of turbulence, together with the time of occurrence of the peak value to the nearest minute, shall be observed. The average and peak values shall be reported in terms of the cube root of EDR. The time of occurrence of the peak value shall be reported as indicated in Table A4-2. The turbulence shall be reported during the climb-out phase for the first 10 minutes of the flight and shall refer to the 30-second period immediately preceding the observation. The peak value of turbulence shall be observed. 2.6.2 Interpretation of the turbulence report Turbulence shall be considered: a) severe when the peak value of EDR equal or exceeds.45; b) moderate when the peak value root of EDR is equal to or above.20 and below 0.45 c) light when the peak value of the cube root of EDR is above 0.10 and below.20 and d) Nil when the peak value of the cube root of EDR is below or equal to 0.10. 2.6.3 Special air-reports Special air-reports on turbulence shall be made during any phase of the flight whenever the peak value of the cube root of EDR equal or exceeds.20 The special air-report on turbulence shall be made with reference to the 1-minute period immediately preceding the observation. Both the average and peak value of turbulence shall be observed. The average and peak values shall be reportedin terms of the cube root of EDR Special air-reports shall be issued every minute until such time as the peak values of the cube root of EDR fall below.20. 2.7 Humidity The humidity shall be reported as the relative humidity, rounded to the nearest Rev. 2, 8 th November 2018 104CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 whole per cent. Note. — The ranges and resolutions for the meteorological elements included in air-reports are shown in Table A4-3. 3 Exchange of Air-Reports 3.1 Responsibilities of the meteorological watch offices 3.1.1 The meteorological watch office shall transmit without delay the special air- reports received by voice communications to WAFCs and the Centre’s designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services. 3.1.2 The meteorological watch office shall transmit without delay special air-reports of pre- eruption volcanic activity, a volcanic eruption or volcanic ash cloud received to the associated VAACs. 3.1.3 When a special air-report is received at the meteorological watch office but the forecaster considers that the phenomenon causing the report is not expected to persist and, therefore, does not warrant issuance of a SIGMET, the special air-report shall be disseminated in the same way that SIGMET messages are disseminated in accordance with Appendix 6, 1.2.1, i.e. to meteorological watch offices, WAFCs, and other meteorological offices in accordance with regional air navigation agreement. Note: -- The template used for special air-reports which are uplinked to aircraft in flights is in Appendix 6, Table A6-1B. 3.2 Responsibilities of world area forecast centres Intentionally left blank 3.3 Supplementary dissemination of air-reports Where supplementary dissemination of air-reports is required to satisfy special aeronautical or meteorological requirements, such dissemination should be arranged and agreed between the meteorological authorities concerned. 3.4 Format of air-reports Air-reports shall be exchanged in the format in which they are received. 4 Specific provisions related to reporting Wind Shear and Volcanic Ash 4.1 Reporting of wind shear 4.1.1 When reporting aircraft observations of wind shear encountered during the climb-out and approach phases of flight, the aircraft type should be included. 4.1.2 Where wind shear conditions in the climb-out or approach phases of flight were reported or forecast but not encountered, the pilot-in-command should advise the appropriate air traffic services unit as soon as practicable unless the pilot- in-command is aware that the appropriate air traffic services unit has already been so advised by a preceding aircraft. Rev. 2, 8 th November 2018 105CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 4.2 Post-flight reporting of volcanic activity Note. — The detailed instructions for recording and reporting volcanic activity observations are given in the PANS-ATM (Doc 4444), Appendix 1. 4.2.1 On arrival of a flight at an aerodrome, the completed report of volcanic activity shall be delivered by the operator or a flight crew member, without delay, to the aerodrome meteorological office, or if such office is not easily accessible to arriving flight crew members, the completed form shall be dealt with in accordance with local arrangements made by the meteorological authority and the operator. 4.2.2 The completed report of volcanic activity received by an aerodrome meteorological office shall be transmitted without delay to the meteorological watch office responsible for the provision of meteorological watch for the flight information region in which the volcanic activity was observed. Rev. 2, 8 th November 2018 106CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Table A4-1: Template for the special air-report (downlink) Key: M = inclusion mandatory, part of every message; C = inclusion conditional; included whenever available. Note. — Message to be prompted by the pilot-in-command. Currently only the condition “SEV TURB” can be automated (see 2.6.3). Element as specified in Para 5 Detailed content Template(s) Examples Message type designator (M) Type of air-report (M) ARS ARS Aircraft identification (M) Aircraft radiotelephony call sign (M) nnnnnn VA812 DATA BLOCK 1 Latitude (M) Latitude in degrees and minutes (M) Nnnnn or Snnnn S4506 Longitude (M) Longitude in degrees and minutes (M) Wnnnnn or Ennnnn E01056 Level (M) Flight level (M) FLnnn or FLnnn to FLnnn FL330 FL280 to FL310 Time (M) Time of occurrence in hours and OBS AT nnnnZ OBS AT 1216Z minutes (M) DATA BLOCK 2 Wind direction (M) Wind direction in degrees true (M) nnn/ 262/ Wind speed (M) Wind speed in metres per second (or nnnMPS (or nnnKT) 40MPS knots) (M) (080KT) Wind quality flag (M) Wind quality flag (M) n 1 Air temperature (M) Air temperature in tenths of degrees C T[M]nnn T127 (M) TM455 Turbulence (C) Turbulence in hundredths of m2/3 s-1 EDRnnn/nn EDR064/08 and the time of occurrence of the peak value (C)1 Humidity (C) Relative humidity in per cent (C) RHnnn RH054 DATA BLOCK 3 Condition prompting the issuance of SEV TURB [EDRnnn]2 or SEV TURB EDR076 a special air-report (M) SEV ICE VA CLD FL050/100 or SEV MTW or TS GR3 or TS3 or HVY SS4 or VA CLD [FL nnn/nnn] or VA5 [MT nnnnnnnnnnnnnnnnnnnn] or MOD TURB [EDRnnn]2 or MOD ICE Notes.— 1. The time of occurrence to be reported in accordance with Table A4-2. 2. The turbulence to be reported in accordance with 2.6.3. 3. Obscured, embedded or widespread thunderstorms or thunderstorms in squall lines. 4. Duststorm or sandstorm. 5. Pre-eruption volcanic activity or a volcanic eruption. Rev. 2, 8 th November 2018 107CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Table A4-2: Time of occurrence of the peak value to be reported Peak value of turbulence during the one-minute period Value to be .... minutes prior to the observation reported 0-1 0 1-2 1 2-3 2 ... ... 13-14 13 14-15 14 No timing information available 15 Table A4-3: Ranges and resolutions for the meteorological elements included in air- reports Element as specified in Para 5 Range Resoluti on Wind direction: °true 000 – 1 360 Wind speed: MPS 00 – 125 1 KT 00 – 250 1 Wind quality flag: (index)* 0 – 1 1 Air temperature: °C –80 – 0.1 +60 Turbulence: routine air-report: m2/3 s-1 0 – 2 0.01 (time of occurrence)* 0 – 15 1 Turbulence: special air-report: m2/3 s-1 0 – 2 0.01 Humidity: % 0 – 100 1 * Non-dimensional Rev. 2, 8 th November 2018 108CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 APPENDIX 5. TECHNICAL SPECIFICATIONS RELATED TO FORECASTS (See Para 6 of this CAR) 1 Criteria related to TAF 1.1 TAF format 1.1.1 TAF shall be issued in accordance with the template shown in Table A5-1 and disseminated in the TAF code form prescribed by the World Meteorological Organization (WMO). Note.— The TAF code form is contained in, Manual on Codes, WMO No. 306, Volume I.1, Part A —Alphanumeric Codes. 1.1.2 Until 4 November 2020, TAF should be disseminated in IWXXM GML form in addition to the dissemination of the TAF in accordance with 1.1.1. 1.1.2 As of 5 November 2020, TAF shall be disseminate in IWXXM GML form in additionto the dissemination of the TAF in accordance with 1.1.1. Note.— The technical specifications for IWXXM are contained in the Manual on Codes (WMO- No. 306), Volume I.3, Part D — Representation Derived from Data Models. Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). 1.2 Inclusion of meteorological elements in TAF Note.— Guidance on operationally desirable accuracy of forecasts is given in Attachment B. 1.2.1 Surface wind In forecasting surface wind, the expected prevailing direction shall be given. When it is not possible to forecast a prevailing surface wind direction due to its expected variability, for example, during light wind conditions (less than 1.5 m/s (3 kt)) or thunderstorms, the forecast wind direction shall be indicated as variable using “VRB”. When the wind is forecast to be less than 0.5 m/s (1 kt), the forecast wind speed shall be indicated as calm. When the forecast maximum speed (gust) exceeds the forecast mean wind speed by 5 m/s (10 kt)or more, the forecast maximum wind speed shall be indicated. When a wind speed of 50 m/s (100 kt) or more is forecast, it shall be indicated to be more than 49 m/s (99 kt). 1.2.2 Visibility When the visibility is forecast to be less than 800 m, it shall be expressed in steps of 50 m; when it is forecast to be 800 m or more but less than 5 km, in steps of 100 m; 5 km or more but less than 10 km, in kilometre steps; and when it is forecast to be 10 km or more, it should be expressed as 10 km, except Rev. 2, 8 th November 2018 109CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 when conditions of CAVOK are forecast to apply. The prevailing visibility should be forecast. When visibility is forecast to vary in different directions and the prevailing visibility cannot be forecast, the lowest forecast visibility should be given. 1.2.3 Weather phenomena One or more, up to a maximum of three, of the following weather phenomena or combinations thereof, together with their characteristics and, where appropriate, intensity, shall be forecast if they are expected to occur at the aerodrome: — freezing precipitation — freezing fog — moderate or heavy precipitation (including showers thereof) — low drifting dust, sand or snow — blowing dust, sand or snow — dust storm — sandstorm — thunderstorm (with or without precipitation) — squall — funnel cloud (tornado or waterspout) — Other weather phenomena given in Appendix 3, 4.4.2.3, as agreed between the meteorological authority the appropriate ATS authority and operators concerned. The expected end of occurrence of those phenomena shall be indicated by the abbreviation “NSW”. 1.2.4 Cloud Cloud amount should be forecast using the abbreviations “FEW”, “SCT”, “BKN” or “OVC” as necessary. When it is expected that the sky will remain or become obscured and clouds cannot be forecast and information on vertical visibility is available at the aerodrome, the vertical visibility shall be forecast in the form “VV” followed by the forecast value of the vertical visibility. When several layers or masses of cloud are forecast, their amount and height of base shall be included in the following order: a) the lowest layer or mass regardless of amount, to be forecast as FEW, SCT, BKN or OVC as appropriate; b) the next layer or mass covering more than 2/8, to be forecast as SCT, BKN or OVC as appropriate; c) the next higher layer or mass covering more than 4/8, to be forecast as BKN or OVC as appropriate; and d) Cumulonimbus clouds and/or towering cumulus clouds, whenever forecastand not already included under a) to c). Cloud information should be limited to cloud of operational significance; when no cloud of operational significance is forecast, and “CAVOK” is not appropriate, the abbreviation “NSC” shall be used. Rev. 2, 8 th November 2018 110CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 1.2.5 Temperature When forecast temperatures are included in accordance with regional air navigation agreement, the maximum and minimum temperatures expected to occur during the period of validity of the TAF should be given, together with their corresponding times of occurrence. 1.3 Use of change groups Note. ― Guidance on the use of change and time indicators in TAF is given in Table A5-2. 1.3.1 The criteria used for the inclusion of change groups in TAF or for the amendment of TAF shall be based on any of the following weather phenomena or combinations thereof being forecast to begin or end or change in intensity: — Freezing fog — freezing precipitation — moderate or heavy precipitation (including showers) — thunderstorm — dust storm — sandstorm 1.3.2 The criteria used for the inclusion of change groups in TAF or for the amendment of TAF should be based on the following: a) when the mean surface wind direction is forecast to change by 60º or more, the mean speed before and/or after the change being 5 m/s (10 kt) or more; b) when the mean surface wind speed is forecast to change by 5 m/s (10 kt) or more; c) when the variation from the mean surface wind speed (gusts) is forecast to change by 5 m/s (10 kt) or more, the mean speed before and/or after the change being 7.5 m/s (15 kt) or more; d) When the surface wind is forecast to change through values of operational significance. The threshold values should be established by the meteorological authority in consultation with the appropriate ATS authority and operators concerned, taking into account changes in the wind which would: 1) require a change in runway(s) in use; and 2) indicate that the runway tailwind and crosswind components will change through values representing the main operating limits for typical aircraft operating at the aerodrome; e) when the visibility is forecast to improve and change to or pass through one or more of the following values, or when the visibility is forecast to deteriorate and pass through one or more of the following values: 1) 150, 350, 600, 800, 1500 or 3000m; or 2) 5000m in cases where significant numbers of flights are operated in accordance with the visual flight rules. Rev. 2, 8 th November 2018 111CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 f) when any of the following weather phenomena or combinations thereof are forecast to begin or end: – low drifting dust, sand or snow – blowing dust, sand or snow – squall – funnel cloud (tornado or waterspout); g) when the height of base of the lowest layer or mass of cloud of BKN or OVC extent is forecast to lift and change to or pass through one or more of the following values, or when the height of the lowest layer or mass of cloud of BKN or OVC extent is forecast to lower and pass through one or more of the following values: 1) 30, 60, 150 or 300 m (100, 200, 500 or 1000 ft); or 2) 450 m (1500 ft) in cases where significant numbers of flights are operated in accordance with the visual flight rules; h) when the amount of a layer or mass of cloud below 450 m (1500 ft) is forecast to change: 1) from NSC, FEW or SCT to BKN or OVC; or 2) from BKN or OVC to NSC, FEW or SCT; i) when the vertical visibility is forecast to improve and change to or pass through one or more of the following values, or when the vertical visibility is forecast to deteriorate and pass through one or more of the following values: 30, 60, 150 or 300 m (100, 200, 500 or 1000 ft); and j) Any other criteria based on local aerodrome operating minima, as agreed between the meteorological authority and the operators concerned. Note. — Other criteria based on local aerodrome operating minima are to be considered in parallel with similar criteria for the issuance of SPECI developed in response to Appendix 3, 2.3.3 h). 1.3.3 When a change in any of the elements given in Para 6, 6.2.3 is required to be indicated in accordance with the criteria given in 1.3.2, the change indicators “BECMG” or “TEMPO” shall be used followed by the time period during which the change is expected to occur. The time period should be indicated as the beginning and end of the period in whole hours UTC. Only those elements for which a significant change is expected should be included following a change indicator. However, in the case of significant changes in respect of cloud, all cloud groups, including layers or masses not expected to change, should be indicated. 1.3.4 The change indicator “BECMG” and the associated time group should be used to describe changes where the meteorological conditions are expected to reach or pass through specified threshold values at a regular or irregular rate and at an unspecified time during the time period. The time period shall normally not exceed 2 hours but in any case should not exceed 4 hours. 1.3.5 The change indicator “TEMPO” and the associated time group should be used to describe expected frequent or infrequent temporary fluctuations in the meteorological conditions which reach or pass specified threshold values and last for a period of less than one hour in each instance and, in the aggregate, cover less than one-half of the forecast period during which the fluctuations are Rev. 2, 8 th November 2018 112CIVIL AVIATION REQUIREMENTS SECTION 9 SERIES M PART I 24 th March 2017 Expected to occur. If the temporary fluctuation is expected to last one hour or longer, the change group “BECMG” should be used in accordance with 1.3.4 or the validity period should be subdivided in accordance with 1.3.6. 1.3.6 Where one set of prevailing weather conditions is expected to change significantly and more or less completely to a different set of conditions, the period of validity shall be subdivided into self-contained periods using the abbreviation “FM” followed immediately by a four-figure time group in whole hours and minutes UTC indicating the time the change is expected to occur. The subdivided period following the abbreviation “FM” should be self-contained and all forecast conditions given before the abbreviation should be superseded by those following the abbreviation. 1.4 Use of probability groups The probability of occurrence of an alternative value of a forecast element or elements should be indicated, as necessary, by use of the abbreviation “PROB” followed by the probability in tens of per cent and the time period during which the alternative value(s) is (are) expected to apply. The probability information shall be placed after the element or elements forecast and be followed by the alternative value of the element or elements. The probability of a forecast of temporary fluctuations in meteorological conditions should be indicated, as necessary, by use of the abbreviation “PROB” followed by the probability in tens of per cent, placed before the change indicator “TEMPO” and associated time group. A probability of an alternative value or change of less than 30 per cent should not be considered sufficiently significant to be indicated. A probability of an alternative value or change of 50 per cent or more, for aviation purposes, should not be considered a probability but instead should be indicated, as necessary, by use of the change indicators “BECMG” or “TEMPO” or by subdivision of the validity period using the abbreviation “FM”. The probability group should not be used to qualify the change indicator “BECMG” nor the time indicator “FM”. 1.5 Numbers of change and probability groups The number of change and probability groups should be kept to a minimum and should not normally exceed five groups. 1.6 Dissemination of TAF TAF and amendments there to shall be disseminated to international OPMET databanks and the centres designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services, in accordance with regional air navigation agreement. 2 Criteria related to Trend Forecasts 2.1 Format of trend forecasts Trend forecasts shall be issued in accordance with the templates shown in Appendix 3, Tables A3-1 and A3-2. The units and scales used in the trend forecast shall be the same as those used in the report to which it is appended. Note. — Examples of trend forecasts are given in Appendix 3. Rev. 2, 8 th November 2018 1132.2 Inclusion of meteorological elements in trend forecasts 2.2.1 General provisions The trend forecast shall indicate significant changes in respect of one or more of the elements: surface wind, visibility, weather and clouds. Only those elements shall be included for which a significant change is expected. However, in the case of significant changes in respect of cloud, all cloud groups, including layers or masses not expected to change, shall be indicated. In the case of a significant change in visibility, the phenomenon causing the reduction of visibility shall also be indicated. When no change is expected to occur, this shall be indicated by the term “NOSIG”. 2.2.2 Surface wind The trend forecast shall indicate changes in the surface wind which involve: a) a change in the mean wind direction of 60° or more, the mean speed before and/or after the change being 5 m/s (10 kt) or more; b) a change in mean wind speed of 5 m/s (10 kt) or more; and c) Changes in the wind through values of operational significance. The threshold values shall be established by the meteorological authority in consultation with the appropriate ATS authority and operators concerned, taking into account changes in the wind which would: 1) require a change in runway(s) in use; and 2) Indicate that the runway tailwind and crosswind components will change through values representing the main operating limits for typical aircraft operating at the aerodrome. 2.2.3 Visibility When the visibility is expected to improve and change to or pass through one or more of the following values, or when the visibility is expected to deteriorateand pass through one or more of the following values: 150, 350, 600, 800, 1500or 3000 m, the trend forecast shall indicate the change. When significant numbers of flights are conducted in accordance with the visual flight rules, the forecast shall additionally indicate changes to or passing through 5000 m. Note. — In trend forecasts appended to local routine and special reports, visibility refers to the forecast visibility along the runway(s); in trend forecasts appended to METAR and SPECI, visibility refers to the forecast prevailing visibility. 2.2.4 Weather phenomena 2.2.4.1 The trend forecast shall indicate the expected onset, cessation or change in intensity of one or more of the following weather phenomena or combinations thereof: — freezing precipitation — moderate or heavy precipitation (including showers) — thunderstorm (with precipitation)— dust storm — sandstorm — Other weather phenomena given in Appendix 3, 4.4.2.3, as agreed by the meteorological authority, the appropriate ATS authority and operators concerned. 2.2.4.2 The trend forecast shall indicate the expected onset or cessation of one or more of the following weather phenomena or combinations thereof: — freezing fog — low drifting dust, sand or snow — blowing dust, sand or snow — thunderstorm (without precipitation) — squall — Funnel cloud (tornado or waterspout). 2.2.4.3 The total number of phenomena reported in 2.2.4.1 and 2.2.4.2 shall not exceed three. 2.2.4.4 The expected end of occurrence of the weather phenomena shall be indicated by the abbreviation “NSW”. 2.2.5 Clouds When the height of the base of a cloud layer of BKN or OVC extent is expected to lift and change to or pass through one or more of the following values, or when the height of the base of a cloud layer of BKN or OVC extent is expected to lower and pass through one or more of the following values: 30, 60, 150, 300 and 450 m (100, 200, 500, 1000 and 1500 ft), the trend forecast shall indicate the change. When the height of the base of a cloud layer is below or is expected to fall below or rise above 450 m (1500 ft), the trend forecast shall also indicate changes in cloud amount from FEW, or SCT increasing to BKN or OVC, or changes from BKN or OVC decreasing to FEW or SCT. When no cloud of operational significance are forecast and “CAVOK” is not appropriate, the abbreviation “NSC” shall be used. 2.2.6 Vertical visibility When the sky is expected to remain or become obscured and vertical visibility observations are available at the aerodrome, and the vertical visibility is forecast to improve and change to or pass through one or more of the following values, or when the vertical visibility is forecast to deteriorate and pass through one or more of the following values: 30, 60, 150 or 300 m (100, 200, 500 or 1000 ft), the trend forecast shall indicate the change. 2.2.7 Additional criteria Criteria for the indication of changes based on local aerodrome operating minima, additional to those specified in 2.2.2 to 2.2.6, shall be used as agreed between the meteorological authority and the operator concerned. 2.3 Use of change groupsNote. ― Guidance on the use of change indicators in trend forecasts is given in Appendix3, Table A3-3. 2.3.1 When a change is expected to occur, the trend forecast shall begin with one of the change indicators “BECMG” or “TEMPO”. 2.3.2 The change indicator “BECMG” shall be used to describe forecast changes where the meteorological conditions are expected to reach or pass through specified values at a regular or irregular rate. The period during which, or the time at which, the change is forecast to occur shall be indicated, using the abbreviations “FM”, “TL” or “AT”, as appropriate, each followed by a time group in hours and minutes. When the change is forecast to begin and end wholly within the trend forecast period, the beginning and end of the change shall be indicated by using the abbreviations “FM” and “TL”, respectively, with their associated time groups. When the change is forecast to commence at the beginning of the trend forecast period but be completed before the end of that period, the abbreviation “FM” and its associated time group shall be omitted and only “TL” and its associated time group shall be used. When the change is forecast to begin during the trend forecast period and be completed at the end of that period, the abbreviation “TL” and its associated time group shall be omitted and only “FM” and its associated time group shall be used. When the change is forecast to occur at a specified time during the trend forecast period, the abbreviation “AT” followed by its associated time group shall be used. When the change is forecast to commence at the beginning of the trend forecast period and be completed by the end of that period or when the change is forecast to occur within the trend forecast period but the time is uncertain, the abbreviations “FM”, “TL” or “AT” and their associated time groups shall be omitted and the change indicator “BECMG” shall be used alone. 2.3.3 The change indicator “TEMPO” shall be used to describe forecast temporary fluctuations in the meteorological conditions which reach or pass specified values and last for a period of less than one hour in each instance and, in the aggregate, cover less than one-half of the period during which the fluctuations are forecast to occur. The period during which the temporary fluctuations are forecast to occur shall be indicated, using the abbreviations “FM” and/or “TL”, as appropriate, each followed by a time group in hours and minutes. When the period of temporary fluctuations in the meteorological conditions is forecast to begin and end wholly within the trend forecast period, the beginning and end of the period of temporary fluctuations shall be indicated by using theabbreviations “FM” and “TL”, respectively, with their associated time groups. When the period of temporary fluctuations is forecast to commence at the beginning of the trend forecast period but cease before the end of that period, the abbreviation “FM” and its associated time group shall be omitted and only “TL” and its associated time group shall be used. When the period of temporaryfluctuations is forecast to begin during the trend forecast period and cease by the end of that period, the abbreviation “TL” and its associated time group shallbe omitted and only “FM” and its associated time group shall be used. When the period of temporary fluctuations is forecast to commence at the beginning of the trend forecast period and cease by the end of that period, both abbreviations “FM” and “TL” and their associated time groups shall be omitted and the change indicator “TEMPO” shall be used alone. 2.4 Use of the probability indicatorThe indicator “PROB” shall not be used in trend forecasts. 3 Criteria related to forecast for Take-off 3.1 Format of forecasts for take-off The format of the forecast should be as agreed between the meteorological authority and the operator concerned. The order of the elements and the terminology, units and scales used in forecasts for take-off should be the same as those used in reports for the same aerodrome. 3.2 Amendments to forecasts for take-off The criteria for the issuance of amendments for forecasts for take-off for surface wind direction and speed, temperature and pressure and any other elements agreed locally should be agreed between the meteorological authority and the operators concerned. The criteria should be consistent with the corresponding criteria for special reports established for the aerodrome in accordance with Appendix 3, 2.3.1. 4 Criteria related to Area Forecast for Low-level flights 4.1 Format and content of GAMET area forecasts Intentionally left blank 4.2 Amendments to GAMET area forecasts Intentionally left blank 4.3 Exchange of area forecasts for low-level flights 4.3.1 When chart form is used for area forecasts for low-level flights, the forecast of upper wind and upper-air temperature shall be issued for points separated by no more than 500 km (300 NM) and for at least the following altitudes: 600, 1 500 and 3 000 m (2 000, 5 000 and 10 000 ft), and 4 500 m (15 000 ft) in mountainous areas. 4.3.2 When chart form is used for area forecasts for low-level flights, the forecast of SIGWX phenomena shall be issued as low-level SIGWX forecast for flight levels up to 100 (or up to flight level 150 in mountainous areas, or higher, where necessary). Low-level SIGWX forecasts shall include the following items: a) the phenomena warranting the issuance of a SIGMET as given in Appendix 6 and which are expected to affect low-level flights; and b) the elements in area forecasts for low-level flights as given in Table A5-3 except elements concerning: 1) upper wind and upper-air temperature; and 2) Forecast QNH. 4.4 Exchange and dissemination of area forecasts for low-level flights4.4.1 Area forecasts for low-level flights prepared in support of the issuance of AIRMET information shall be exchanged between aerodrome meteorological offices and/or meteorological watch offices responsible for the issuance of flight documentation for low-level flights in the flight information regions concerned. 4.4.2 Recommendation.—Area forecasts for low-level flights, in support of international air navigation, prepared in accordance with regional air navigation agreement and in support of the issuance of AIRMET information should be disseminated to the aeronautical fixed service Internet-based Services. Table A5-1. Template for TAF Key: M = inclusion mandatory, part of every message; C = inclusion conditional, dependent on meteorological conditions or method of observation; O = inclusion optional. Note 1.— The ranges and resolutions for the numerical elements included in TAF are shown in Table A5-4 of this appendix. Note 2. — The explanations for the abbreviations can be found in the Procedures for Air Navigation Services — ICAO Abbreviations and Codes (PANS-ABC, Doc 8400). Element as specified in Para 6 Detailed content Template(s) Examples Identification of the type Type of forecast (M) TAF or TAF AMD or TAF COR TAF of forecast (M) TAF AMD Location indicator (M) ICAO location indicator (M) nnnn YUDO1 Time of issue of Day and time of issue of the nnnnnnZ 160000Z forecast (M) forecast in UTC (M) Identification of a Missing forecast identifier (C) NIL NIL missing forecast (C) END OF TAF IF THE FORECAST IS MISSING. Days and period of Days and period of the nnnn/nnnn 1606/1624 validity of forecast (M) validity of the forecast in UTC 0812/0918 (M) Identification of a Cancelled forecast identifier CNL CNL cancelled forecast (C) (C) END OF TAF IF THE FORECAST IS CANCELLED. Surface wind (M) Wind direction (M) nnn or VRB2 24004MPS; VRB01MPS (24008KT); (VRB02KT) 19005MPS Wind speed (M) [P]nn[n] (19010KT) 00000MPS (00000KT) Significant speed variations G[P]nn[n] 140P49MPS (140P99KT) (C)3 12003G09MPS Units of measurement (M) MPS (or KT) (12006G18KT) 24008G14MPS (24016G28KT) Visibility (M) Prevailing visibility (M) nnnn C 0350 CAVOK A 7000 V 9000 9999Weather (C)4, 5 Intensity of – or + — O RA HZ weather K +TSRA FG phenomena (C)6 –FZDZ PRFG Characteristics and type of DZ or RA or SN IC or FG or weather phenomena (C)7 or SG or PL or BR or SA or +TSRAS DS or SS or DU or HZ or FZDZ or FU or VA or N SNRA FZRA or SQ or PO or SHGR or FC or TS or FG BCFG orElement as specified in Detailed content Template(s) Examples Para 6 SHGS or SHRA BLDU or or SHSN or BLSA or TSGR or TSGS BLSN or or TSRA or DRDU or TSSN DRSA or DRSN or FZFG or MIFG or PRFG Cloud (M)8 Cloud amount FEWnnn VVnnn NSC FEW010 VV005 and height of or or VV/// OVC020 VV/// base or vertical SCTnnn or visibility (M) BKNnnn NSC or OVCnnn SCT005 BKN012 Cloud type (C)4 CB or TCU — SCT008 BKN025CB Temperature (O)9 Name of the element (M) TX TX25/1013Z TN09/1005Z Maximum temperature (M) [M]nn/ TX05/2112Z Day and time of occurrence nnnnZ TNM02/2103Z of the maximum temperature (M) Name of the element (M) TN Minimum temperature (M) [M]nn/ Day and time of occurrence nnnnZ of the minimum temperature (M) Expected Change or PROB30 [TEMPO] or PROB40 [TEMPO] or TEMPO 0815/0818 significant changes probability BECMG or 25017G25MPS (TEMPO to one or more of indicator (M) TEMPO or FM 0815/0818 25034G50KT) the above elements Period of nnnn/nnnn or nnnnnn11 during the period of occurrence or TEMPO 2212/2214 validity (C)4, 10 change (M) 17006G13MPS 1000 TSRA SCT010CB BKN020 Wind (C)4 nnn[P]nn[n][G[P]nn[n]]MPS or (TEMPO 2212/2214 17012G26KT VRBnnMPS 1000 TSRA SCT010CB BKN020) (or nnn[P]nn[G[P]nn]KT BECMG 3010/3011 00000MPS or VRBnnKT) 2400 OVC010 Prevailing visibility (C)4 nnnn C (BECMG 3010/3011 00000KT A 2400 OVC010) V PROB30 1412/1414 0800 FG O Weather – or + — NSW BECMG 1412/1414 RA K phenomenon: TEMPO 2503/2504 intensity (C)6 FZRA TEMPO 0612/0615 BLSN PROB40 TEMPO 2923/3001 0500 FG Weather DZ or RA or FG or BR phenomenon: SN or SG or or SA or characteristics and PL or DS or DU or HZ type (C)4, 7 SS or or FU or FZDZ or VA or SQ FZRA or or PO orFC SHGR or or TS or SHGS or BCFG or BLDU orElement as specified in Para 6 Detailed content Template(s) Examples SHRA or BLSA or SHSN or BLSN or TSGR or DRDU or TSGS or DRSA or TSRA or DRSN or TSSN FZFG or MIFG or PRFG Cloud amount and height of FEWnnn or VVnnn NSC FM051230 15015KMH 9999 BKN020 base or vertical visibility (C)4 SCTnnn or or VV/// (FM051230 15008KT 9999 BKN020) BKNnnn or OVCnnn BECMG 1618/1620 8000 NSW NSC Cloud type (C)4 CB or TCU — BECMG 2306/2308 SCT015CB BKN020 Notes.— 1. Fictitious location. 2. To be used in accordance with 1.2.1. 3. To be included in accordancewith 1.2.1. 4. To be included whenever applicable. 5. One or more, up to a maximum of three, groups in accordance with 1.2.3. 6. To be included whenever applicable in accordance with 1.2.3. No qualifier for moderate intensity. 7. Weather phenomena to be included in accordance with 1.2.3. 8. Up to four cloud layers in accordance with 1.2.4. 9. To be included in accordance with 1.2.5, consisting of up to a maximum of four temperatures (two maximum temperatures and two minimum temperatures). 10. To be included in accordance with 1.3, 1.4 and 1.5. 11. To be used with FM only.Table A5-2. Use of change and time indicators in TAF Change or time indicator Time period Meanin g FM ndndnhnhnmnm used to indicate a significant change in most weather elements occurring at ndnd day, nhnh hours and nmnm minutes (UTC); all the elements given before “FM” are to be included following “FM” (i.e. they are all superseded by those following the abbreviation) BECMG nd1nd1nh1nh1/nd2nd2nh2 the change is forecast to commence at nd1nd1 day and nh1nh1 hours (UTC) and be completed by nh2 nd2nd2 day and nh2nh2 hours (UTC); only those elements for which a change is forecast are to be given following “BECMG”; the time period nd1nd1nh1nh1/nd2nd2nh2nh2 should normally be less than 2 hours and in any case should not exceed 4 hours TEMPO nd1nd1nh1nh1/nd2nd2nh2 temporary fluctuations are forecast to commence at nd1nd1 day and nh1nh1 hours (UTC) and cease nh2 by nd2nd2 day and nh2nh2 hours (UTC); only those elements for which fluctuations are forecast are to be given following “TEMPO”; temporary fluctuations should not last more than one hour in each instance, and in the aggregate, cover less than half of the period nd1nd1nh1nh1/nd2nd2nh2nh2 probability of occurrence (in %) of an PROBnn — nd1nd1nh1nh1/nd2nd2nh2 — alternative nh2 value of a forecast element or elements; TEMPO nd1nd1nh1nh1/nd2nd2nh2 nn = 30 or nn = 40 only; probability of occurrence of nh2 temporary fluctuations to be placed after the element(s) concerned Table A5-3. Template for GAMET Intentionally left blank Table A5-4. Ranges and resolutions for the numerical elements included in TAF Element as specified in Para 6 Range Resolution Wind direction: ° true 000 – 360 10 Wind speed: MP 00 – 99* 1 S 00 – 199* 1 K T Visibility: M 0000 – 50 M 0750 100 M 0800 – 4 1 000 M 900 0 (fixed value: 9 999) 5 000 – 9 000 10 000 – Vertical visibility: 30’s M (100’s FT) 000 – 020 1 Cloud: height of cloud base: 30’s M (100’s FT) 000 – 100 1 Air temperature (maximum and minimum): °C –80 – +60 1 * There is no aeronautical requirement to report surface wind speeds of 50 m/s (100 kt) or more; however, provision has been made for reporting wind speeds up to 99 m/s (199 kt) for non-aeronautical purposes, as necessary.Example A5-1. TAF TAF for YUDO (Donlon/International)*: TAF YUDO 160000Z 1606/1624 13005MPS 9000 BKN020 BECMG 1606/1608 SCT015CB BKN020 TEMPO 1608/1612 17006G12MPS 1000 TSRA SCT010CB BKN020 FM161230 15004MPS 9999 BKN020 Meaning of the forecast: TAF for Donlon/International* issued on the 16th of the month at 0000 UTC valid from 0600 UTC to 2400 UTC on the 16th of the month; surface wind direction 130 degrees; wind speed 5 metres per second; visibility 9 kilometres, broken cloud at 600 metres; becoming between 0600 UTC and 0800 UTC on the 16th of the month, scattered cumulonimbus cloud at 450 metres and broken cloud at 600 metres; temporarily between 0800 UTC and 1200 UTC on the 16th of the month surface wind direction 170 degrees; wind speed 6 metres per second gusting to 12 metres per second; visibility 1 000 metres in a thunderstorm with moderate rain, scattered cumulonimbus cloud at 300 metres and broken cloud at 600 metres; from 1230 UTC on the 16th of the month surface wind direction 150 degrees; wind speed 4 metres per second; visibility 10 kilometres or more; and broken cloud at 600 metres. * Fictitious location Note.— In this example, the primary units “metre per second” and “metre” were used for wind speed and height of cloud base, respectively. However, in accordance with Annex 5, the corresponding non-SI alternative units “knot” and “foot” may be used instead. Example A5-2. Cancellation of TAF Cancellation of TAF for YUDO (Donlon/International)*: TAF AMD YUDO 161500Z 1606/1624 CNL Meaning of the forecast: Amended TAF for Donlon/International* issued on the 16th of the month at 1500 UTC cancelling the previously issued TAF valid from 0600 UTC to 2400 UTC on the 16th of the month. * Fictitious location Example A5-3. GAMET area forecast Intentionally left blankAPPENDIX 6. TECHNICAL SPECIFICATIONS RELATED TO SIGMET AND AIRMET INFORMATION, AERODROME WARNINGS AND WIND SHEAR WARNINGS AND ALERTS (See Para 7 of this CAR.) Note.— Data type designators to be used in abbreviated headings for SIGMET, AIRMET, tropical cyclone and volcanic ash advisory messages are given in Manual on the Global Telecommunication System (WMO-No. 386). 1 Specifications related to SIGMET information 1.1 Format of SIGMET messages 1.1.1 The content and order of elements in a SIGMET message shall be in accordance with the template shown in Table A6-1A. 1.1.2 Messages containing SIGMET information shall be identified as: “SIGMET”. 1.1.3 The sequence number referred to in the template in Table A6-1A shall correspond with the number of SIGMET messages issued for the flight information region (FIR) since 0001 UTC on the day concerned. The meteorological watch offices whose area of responsibility encompasses more than one FIR and/or control area (CTA) shall issue separate SIGMET messages for each FIR and/or CTA within their area of responsibility. 1.1.4 In accordance with the template in Table A6-1A, only one of the following phenomena shall be included in a SIGMET message, using the abbreviations as indicated below: At cruising levels (irrespective of altitude): thunderstorm — obscured OBSC TS — embedded EMBD TS — frequent FRQ TS — squall line SQL TS — obscured with hail OBSC TSGR — embedded with hail EMBD TSGR — frequent, with hail FRQ TSGR — squall line with hail SQL TSGR tropical cyclone — tropical cyclone with 10-minute mean TC (+ cyclone name) surface wind speed of 17 m/s (34 kt) or more turbulence — severe turbulence SEV TURB icing — severe icing SEV ICE— severe icing due to freezing rain SEV ICE (FZRA) mountain wave — severe mountain wave SEV MTW dust storm — heavy dust storm HVY DS sandstorm — heavy sandstorm HVY SS volcanic ash — volcanic ash VA (+ volcano name, if known) radioactive cloud RDOACT CLD 1.1.5 SIGMET information shall not contain unnecessary descriptive material. In describing the weather phenomena for which the SIGMET is issued, no descriptive material additional to that given in 1.1.4 shall be included. SIGMET information concerning thunderstorms or a tropical cyclone shall not include references to associated turbulence and icing. 1.1.6 Until 4 November 20202, SIGMET information should be disseminated in IWXXM GML form, in addition to the dissemination of SIGMET information in accordance with 1.1.1. 1.1.6 As of 5 November 2020, SIGMET information shall be disseminate in IWXXM GML form in addition to the dissemination of SIGMET information in accordance with 1.1.1. Note. — The technical specifications for IWXXM are contained in the Manual on Codes (WMO-No. 306), Volume I.3, and Part D— Representation Derived from Data Models. Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). 1.1.7 SIGMET, when issued in graphical format, should be as specified in Appendix 1, including the use of applicable symbols and/or abbreviations. 1.2 Dissemination of SIGMET messages 1.2.1 SIGMET messages shall be disseminated to meteorological watch offices, WAFCs and to other meteorological offices in accordance with regional air navigation agreement. SIGMET messages for volcanic ash shall also be disseminated to VAACs. 1.2.2 SIGMET messages shall be disseminated to international OPMET databanks and the centers designated by regional air navigation agreement for the operation of aeronautical fixed service satellite distribution systems, in accordance with regional air navigation agreement. 2 Specification related to AIRMET Information 2.1 Format of AIRMET messagesIntentionally left blank 2.2 Dissemination of AIRMET messages Intentionally left blank 3 SPECIFICATIONS RELATED TO SPECIAL AIR-REPORTS Intentionally left blank 3.1 Intentionally left blank 3.2 Intentionally left blank 4 Detailed criteria related to SIGMET, AIRMET messages and Special Air- Reports (Uplink) 4.1 Identification of the flight information region (FIR) In cases where the airspace is divided into a flight information region (FIR) and an upper flight information region (UIR), the SIGMET should be identified by the location indicator of the air traffic services unit serving the FIR. Note. — The SIGMET message applies to the whole airspace within the lateral limits of the FIR, i.e. to the FIR and to the UIR. The particular areas and/or flight levels affected by the meteorological phenomena causing the issuance of the SIGMET are given in the text of the message. 4.2 Criteria related to phenomena included in SIGMET, AIRMET messages and special air-reports (uplink) 4.2.1 An area of thunderstorms and cumulonimbus clouds should be considered: a) obscured (OBSC) if it is obscured by haze or smoke or cannot be readily seen due to darkness; and b) Embedded (EMBD) if it is embedded within cloud layers and cannot be readily recognized. c) isolated (ISOL) if it consists of individual features which affect, or are forecast to affect, an area with a maximum spatial coverage less than 50 per cent of the area concerned (at a fixed time or during the period of validity); and d) occasional (OCNL) if it consists of well-separated features which affect, or are forecast to affect, an area with a maximum spatial coverage between 50 and 75 per cent of the area concerned (at a fixed time or during the period of validity). 4.2.2 An area of thunderstorms should be considered frequent (FRQ) if within that area there is little or no separation between adjacent thunderstorms with a maximum spatial coverage greater than 75 per cent of the area affected, or forecast to be affected, by the phenomenon (at a fixed time or during the period of validity). 4.2.3 Squall line (SQL) should indicate a thunderstorm along a line with little or no space between individual clouds.4.2.4 Hail (GR) should be used as a further description of the thunderstorm, as necessary. 4.2.5 Severe and moderate turbulence (TURB) should refer only to: low-level turbulence associated with strong surface winds; rotor streaming; or turbulence whether in cloud or not in cloud (CAT). Turbulence should not be used in connection with convective clouds. 4.2.6 Turbulence shall be considered: a) severe whenever the peak value of EDR equals or exceeds.45; and b) Moderate whenever the peak value of EDR is equals to or above.20 and below.0.4 4.2.7 Severe and moderate icing (ICE) should refer to icing in other than convective clouds. Freezing rain (FZRA) should refer to severe icing conditions caused by freezing rain. 4.2.8 A mountain wave (MTW) should be considered: a) severe whenever an accompanying downdraft of 3.0 m/s (600 ft/min) or more and/or severe turbulence is observed or forecast; and b) Moderate whenever an accompanying downdraft of 1.75–3.0 m/s (350– 600 ft./min) and/or moderate turbulence is observed or forecast. 4.2.9 Sandstorm/dust storm should be considered: a) heavy whenever the visibility is below 200 m and the sky is obscured; and b) moderate whenever the visibility is: 1) below 200 m and the sky is not obscured; or 2) Between 200 m and 600 m. 5 Specifications related to Aerodrome Warnings 5.1 Format and dissemination of aerodrome warnings 5.1.1 The aerodrome warnings shall be issued in accordance with the template in Table A6-2 where required by operators or aerodrome services, and shall be disseminated in accordance with local arrangements to those concerned. 5.1.2 The sequence number referred to in the template in Table A6-2 shall correspond with the number of aerodrome warnings issued for the aerodrome since 0001 UTC on the day concerned. 5.1.3 In accordance with the template in Table A6-2, aerodrome warnings should relate to the occurrence or expected occurrence of one or more of the following phenomena: – tropical cyclone (to be included if the 10-minute mean surface wind speed at the aerodrome is expected to be 17 m/s (34 kt) or more) – thunderstorm – hail– snow (including the expected or observed snow accumulation) – freezing precipitation – hoar frost or rime – sandstorm – duststorm – rising sand or dust – strong surface wind and gusts – squall – frost – volcanic ash – tsunami – volcanic ash deposition – toxic chemicals – other phenomena as agreed locally. Note.— Aerodrome warnings related to the occurrence or expected occurrence of tsunami are not required where a national public safety plan for tsunami is integrated with the “at risk” aerodrome concerned. 5.1.4 The use of text additional to the abbreviations listed in the template in Table A6- 2 should be kept to a minimum. The additional text should be prepared in abbreviated plain language using approved ICAO abbreviations and numerical values. If no ICAO approved abbreviations are available, English plain language text should be used. 5.2 Quantitative criteria for aerodrome warnings When quantitative criteria are necessary for the issue of aerodrome warnings covering, for example, the expected maximum wind speed or the expected total snowfall, the criteria used should be as agreed between the aerodrome meteorological office and the users concerned. 6 Specifications related to Wind Shear Warnings 6.1 Detection of wind shear Evidence of the existence of wind shear should be derived from: a) ground-based, wind shear remote-sensing equipment, for example, Doppler radar; b) ground-based, wind shear detection equipment, for example, a system of surface wind and/or pressure sensors located in an array monitoring a specific runway or runways and associated approach and departure paths; c) aircraft observations during the climb-out or approach phases of flight to be made in accordance with Para 5; or d) other meteorological information, for example, from appropriate sensors located on existing masts or towers in the vicinity of the aerodrome ornearby areas of high ground. Note.— Wind shear conditions are normally associated with the following phenomena: — thunderstorms, microbursts, funnel cloud (tornado or waterspout), and gust fronts — strong surface winds coupled with local topography — sea breeze fronts — mountain waves (including low-level rotors in the terminal area) — low-level temperature inversions. 6.2 Format and dissemination of wind shear warnings and alerts Note.— Information on wind shear is also to be included as supplementary information in local routine reports, local special reports, METAR and SPECI in accordance with the templates in Tables A3-1 and A3-2. 6.2.1 The wind shear warnings shall be issued in accordance with the template in Table A6-3 and shall be disseminated in accordance with local arrangements to those concerned. 6.2.2 The sequence number referred to in the template in Table A6-3 shall correspond with the number of wind shear warnings issued for the aerodrome since 0001 UTC on the day concerned. 6.2.3 The use of text additional to the abbreviations listed in the template in Table A6- 3 should be kept to a minimum. The additional text should be prepared in abbreviated plain language using approved ICAO abbreviations and numerical values. If no ICAO approved abbreviations are available, English plain language text should be used. 6.2.4 When an aircraft report is used to prepare a wind shear warning, or to confirm a warning previously issued, the corresponding aircraft report, including the aircraft type, should be disseminated unchanged in accordance with local arrangements to those concerned. Note 1.— Following reported encounters by both arriving and departing aircraft, two different wind shear warnings may exist: one for arriving aircraft and one for departing aircraft. Note 2.— Specifications for reporting the intensity of wind shear are still undergoing development. It is recognized, however, that pilots, when reporting wind shear, may use the qualifying terms “moderate”, “strong” or “severe”, based to a large extent on their subjective assessment of the intensity of the wind shear encountered. 6.2.5 The wind shear alerts shall be disseminated from automated, ground-based, wind shear remote-sensing or detection equipment in accordance with local arrangements to those concerned. 6.2.6 Where microbursts are observed, reported by pilots or detected by ground- based, wind shear detection or remote-sensing equipment, the wind shear warning and wind shear alert should include a specific reference to microburst. 6.2.7 Where information from ground-based, wind shear detection or remote-sensingequipment is used to prepare a wind shear alert, the alert shall, if practicable, relate to specific sections of the runway and distances along the approach path or take- off path as agreed between the meteorological authority, the appropriate ATS authority and the operators concerned. Table A6-1A. Template for SIGMET and AIRMET Message Key: M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable; = = a double line indicates that the text following it should be placed on the subsequent line. Note 1.— The ranges and resolutions for the numerical elements included in SIGMET/AIRMET messages are shown in Table A6-4 of this appendix. Note 2.— In accordance with 1.1.5 and 2.1.5, severe or moderate icing and severe or moderate turbulence (SEV ICE, MOD ICE, SEV TURB, MOD TURB) associated with thunderstorms, cumulonimbus clouds or tropical cyclones should not be included. SIGMET message AIRMET message Element Detailed content SIGMET template AIRMET template examples examples Location indicator of ICAO location indicator of nnnn YUCC2 FIR/CTA (M)1 the ATS unit serving the YUDD2 FIR or CTA to which the SIGMET/AIRMET refers Identification (M) Message identification and SIGMET [n][n]n AIRMET [n][n]n SIGMET 1 AIRMET 9 sequence number3 SIGMET 01 AIRMET 19 SIGMET A01 AIRMET B19 Validity period (M) Day-time groups indicating VALID nnnnnn/nnnnnn VALID 010000/010400 the period of validity in UTC VALID 221215/221600 VALID 101520/101800 VALID 251600/252200 VALID 152000/160000 VALID 192300/200300 Location indicator of Location indicator of MWO nnnn– YUDO2 MWO (M) originating the message with YUSO2 a separating hyphen Name of the FIR/CTA Location indicator and nnnn nnnnnnnnnn nnnn nnnnnnnnnn YUCC AMSWELL YUCC AMSWELL (M) name of the FIR/CTA4 for FIR or FIR[/n] FIR2 YUDD FIR/22 YUDD which the SIGMET/AIRMET UIR or SHANLON2 FIR/UIR2 SHANLON FIR2 is issued UIR FIR/UIR FIR/UIR or YUDD SHANLON nnnn nnnnnnnnnn CTA2 CTA IF THE SIGMET OR AIRMET MESSAGE IS TO BE CANCELLED, SEE DETAILS AT THE END OF THE TEMPLATE. Status indicator (C)5 Indicator of test or exercise TEST or EXER TEST or EXER TEST TEST EXER EXERPhenomenon (M) 6 Description of OBSC7 TS[GR8] SFC WIND OBSC TS OBSC SFC WIND 040/40MPS phenomenon causing the EMBD9 TS[GR8] nnn/nn[n]MPS (or TSGR EMBD TS SFC WIND 310/20KT issuance of FRQ10 TS[GR8] SFC WIND EMBD TSGR FRQ SIGMET/AIRMET SQL11 TS[GR8] nnn/nn[n]KT) TS FRQ TSGR SFC VIS 1500M (BR) SQL TS TC nnnnnnnnnn SFC VIS [n][n]nnM SQL TSGR ISOL TS PSN Nnn[nn] or (nn)16 ISOL TSGR Snn[nn] Wnnn[nn] TC GLORIA PSN OCNL TS OCNL TSGR or Ennn[nn] CB or ISOL17 TS[GR78] N10 W060 CB TC NN12 PSN OCN18 TS[GR78] TC NN PSN MT OBSC Nnn[nn] or Snn[nn] S2030 E06030 CB Wnnn[nn] MT OBSC BKN CLD 120/900M or Ennn[nn] CB SEV TURB SEV BKN CLD 400/3000FT BKN CLD ICE BKN CLD 1000/5000FT SEV TURB13 SEV nnn/[ABV][n[nnnM SEV ICE (FZRA) BKN CLD SFC/3000M ICE14 (or BKN CLD SEV MTW BKN CLD SEV ICE (FZRA)14 [n]nnn/[ABV][n]nnnnF SFC/ABV10000FT SEV MTW15 T) or BKN CLD OVC CLD HVY DS SFC/[ABV][n]nnnM 270/ABV3000M (or BKN CLDSIGMET message AIRMET message Element Detailed content SIGMET template AIRMET template examples examples HVY SS SFC/[ABV][n]nnnnFT) HVY OVC CLD [VA ERUPTION] OVC CLD DS 900/ABV10000FT [MT nnnnnnnnnn] nnn/[ABV]nnnnM HVY OVC CLD [PSN Nnn[nn] or (or OVC CLD SS 1000/5000FT Snn[nn] Ennn[nn] or [n]nnn/[ABV][n]nnnnF Wnnn[nn]] VA CLD T) VA ERUPTION MT OVC CLD or OVC CLD ASHVAL2 PSN S15 SFC/3000M OVC CLD RDOACT CLD SFC/[ABV][n]nnnM E073 VA CLD SFC/ABV10000FT (or OVC CLD SFC/[ABV][n]nnnnFT) RDOACT CLD ISOL CB OCNL CB ISOL17 CB19 FRQ CB OCNL18 CB19 FRQ10 CB19 ISOL TCU ISOL17 TCU19 OCNL TCU OCNL18 TCU19 FRQ TCU FRQ10 TCU19 MOD TURB MOD TURB13 MOD ICE MOD ICE14 MOD MOD MTW MTW15 Observed or forecast Indication whether the OBS [AT nnnnZ] or OBS phenomenon (M)20, 21 information is FCST [AT nnnnZ] OBS AT 1210Z observed FCST and expected to FCST AT 1815Z continue, or forecast Location (C)20, 21, 33 Location (referring Nnn[nn] Wnnn[nn] or Nnn[nn] Ennn[nn] or N2020 W07005 to latitude and Snn[nn] Wnnn[nn] or Snn[nn] Ennn[nn] N48 E010 longitude (in S60 W160 S0530 degrees and or E16530 minutes)) N OF Nnn[nn] or S OF Nnn[nn] or N OF Snn[nn] or S OF Snn[nn] [AND] N OF N50 W OF Wnnn[nn] or E OF Wnnn[nn] or W OF S OF N5430 Ennn[nn] or E OF Ennn[nn] N OF S10 S OF S4530 or W OF W155 E N OF Nnn[nn] or N OF Snn[nn] AND S OF OF W45 Nnn[nn] or S OF Snn[nn] W OF E15540 E OF E09015 or W OF Wnnn[nn] or W OF Ennn[nn] AND N OF N1515 AND W OF E13530 E OF Wnnn[nn] or E OF Ennn[nn] S OF N45 AND N OF N40 or N OF LINE S2520 W11510 – S2520 N OF LINE22 or NE OF LINE 22 or E OF LINE 22 W12010 SW OF LINE N50 W005 – or SE OF LINE 22 or S OF LINE 22 or SW OF N60 W020 LINE22 or W OF LINE 22 SW OF LINE N50 W020 – N45 E010 AND NE or NW OF LINE 22 Nnn[nn] or Snn[nn] Wnnn[nn] OF LINE N45 W020 – N40 E010 or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or WI N6030 E02550 – N6055 Ennn[nn] [– Nnn[nn] or Snn[nn] Wnnn[nn] or E02500 – N6050 E02630 – Ennn[nn]] [– Nnn[nn] or Snn[nn] Wnnn[nn] or N6030 E02550 Ennn[nn]] [AND N OF LINE2122 or NE OF LINE21 22 or E OF LINE 22 or SE OF LINE 22or S OF APRX 50KM WID LINE BTN N64 W017 – N60 LINE 22 or SW OF LINE22or W OF LINE22or NW W010 – N57 E010 OF LINE22 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]]]SIGMET message AIRMET message Element Detailed content SIGMET template AIRMET template examples examples or ENTIRE FIR WI21, 22 23Nnn[nn] or Snn[nn] Wnnn[nn] or ENTIRE UIR Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] ENTIRE FIR/UIR Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – ENTIRE CTA Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] WI 400KM OF TC CENTRE WI 250NM or OF TC CENTRE APRX nnKM WID LINE21 22 BTN (or nnNM WID LINE22 BTN) Nnn[nn] or Snn[nn] Wnnn[nn] orEnnn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] WI 30KM OF N6030 E02550† or Ennn[nn] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] [– Nnn[nn] or Snn[nn] Wnnn[nn] orEnnn[nn]] or ENTIRE UIR or ENTIRE FIR or ENTIRE FIR/UIR ENTIRE CTA or2224 WI nnnKM (or nnnNM) OF TC CENTRE or25 WI nnKM (or nnNM) of Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] Level (C)20, 2124 Flight level or altitude23 [SFC/]FLnnn or FL180 SFC/FL070 [SFC/]nnnnM (or [SFC/][n]nnnnFT) or SFC/3000M FLnnn/nnn or SFC/10000FT FL050/080 TOP TOP FLnnn or FL390 ABV FL250 [TOP] ABV FLnnn or (or [TOP] ABV TOP ABV FL100 [n]nnnnFT) ABV 7000FT [nnnn/]nnnnM (or [[n]nnnn/][n]nnnnFT) or TOP ABV 9000FT [nnnnM/]FLnnn (or [[n]nnnnFT/]FLnnn) TOP ABV 10000FT 3000M 2000/3000M or 24 8000FT 6000/12000FT TOP [ABV or BLW] FLnnn 2000M/FL150 10000FT/FL250 TOP FL500 TOP ABV FL500 TOP BLW FL450 Movement or expected Movement or MOV N [nnKMH] or MOV NNE MOV SE movement (C)20, 26,34 expected movement [nnKMH] or MOV NE [nnKMH] or MOV (direction and MOV ENE [nnKMH] or MOV E NNW speed) with [nnKMH] or MOV ESE [nnKMH] or reference to one of MOV SE [nnKMH] or MOV SSE MOV E 40KMH the sixteen points of [nnKMH] or MOV S [nnKMH] or MOV E 20KT compass, or MOV SSW [nnKMH] or MOV SW MOV WSW 20KT stationary [nnKMH] or MOV WSW [nnKMH] or MOV W [nnKMH] or MOV WNW STNR [nnKMH] or MOV NW [nnKMH] or MOV NNW [nnKMH] (or MOV N [nnKT] or MOV NNE [nnKT] or MOV NE [nnKT] or MOV ENE [nnKT] or MOV E [nnKT] or MOV ESE [nnKT] or MOV SE [nnKT] or MOV SSE [nnKT] or MOV S [nnKT] or MOV SSW [nnKT] or MOV SW [nnKT] or MOV WSW [nnKT] or MOV W [nnKT] or MOV WNW [nnKT] or MOV NW [nnKT] or MOV NNW [nnKT]) Or STNRAIRMET SIGMET message AIRMET message template Element Detailed content SIGMET template examples examples Changes in intensity (C)20 Expected changes in INTSF or INTSF WKN intensity WKN or NC NC Forecast time (C)20,21 26 Indication of the FCST AT nnnnZ — FCST AT 2200Z — forecast time of phenomenon TC Forecast Position (c)24 Forecast position of TC CENTRE PSN — TC CENTRE PSN — TC centre Nnn[nn] or Snn[nn] N1030 E16015 Wnnn[nn] or TC CENTRE PSN Ennn[nn]or31 TC N1015 CENTRE PSN Nnn[nn] or Snn[nn] Wnnn[nn] or E15030 CB Ennn[nn] CB Forecast position (C)20, 21 Forecast position of Nnn[nn] Wnnn[nn] or — N30 W170 — 27,33 phenomenon at the Nnn[nn] Ennn[nn] or end of the validity Snn[nn] Wnnn[nn] or N OF N30 period of the Snn[nn] Ennn[nn] S OF S50 AND W SIGMET message32 OF E170 or N OF Nnn[nn] or S OF N46 AND N OF S OF Nnn[nn] or N39 N OF Snn[nn] or S OF Snn[nn] [AND] NE OF LINE N35 W OF Wnnn[nn] or W020 – N45 W040 E OF Wnnn[nn] or W OF Ennn[nn] or E SW OF LINE N48 OF Ennn[nn] W020 – N43 E010 AND NE OF LINE N43 or W020 – N38 E010 N OF Nnn[nn] or N OF Snn[nn] AND S OF WI N20 W090 – Nnn[nn] or S OF Snn[nn] N05 W090 – N10 or W100 – N20 W100 – W OF Wnnn[nn] or N20 W090 W OF Ennn[nn] AND E OF APRX 50KM WID Wnnn[nn] or E OF LINE BTN N64 Ennn[nn] W017 – N57 W005 – N55 E010 or – N OF LINE22 or NE OF N55 E030 LINE 22or E OF LINE22or SE OF LINE22or S OF ENTIRE FIR LINE 22or SW OF LINE22 or W OF LINE22or ENTIRE UIR NW OF LINE 22Nnn[nn] or Snn[nn] Wnnn[nn] or ENTIRE FIR/UIR Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or ENTIRE CTA Ennn[nn] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] NO VA EXP [AND N OF LINE22 or NE OF LINE 22 or WI 30KM OF N6030 E OF LINE 22or SE OF E02550† LINE22or S OF LINE 22or WI 150NM OF TC CENTRE SW OF LINE 22or W OF LINE 22 or NW OF LINE 22Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]]]SIGMET message AIRMET message Element Detailed content SIGMET template AIRMET examples examples template or WI22, 23 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] or APRX nnKM WID LINE21 22 BTN (nnNM WID LINE21 22BTN) Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] [ – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or ENTIRE FIR or ENTIRE UIR or ENTIRE FIR/UIR or ENTIRE CTA or28 NO VA EXP or 25 WI nnKM(or nnNM) OF Nnn[nn] or Snn[nn] or Wnnn[nn] or Ennn[nn] or24 WI nnnKM (nnnNM) OF TC CENTRE Repetition of elements Repetition of [AND]27 — AND — (C)27 elements included in a SIGMET message for volcanic ash cloud or tropical cyclone Or Cancellation of Cancellation of CNL SIGMET [n][n]n CNL AIRMET [n][n]n CNL SIGMET 2 CNL AIRMET 05 SIGMET/ AIRMET SIGMET/AIRMET nnnnnn/nnnnnn nnnnnn/nnnnnn 101200/101600 151520/151800 (C)29 referring to its identification or2728 CNL SIGMET A13 CNL SIGMET 251030/251430 VA [n][n]n nnnnnn/nnnnnn MOV TO YUDO FIR2 VA MOV TO nnnn FIR Notes.— 1. See 4.1. 2. Fictitious location. 3. In accordance with 1.1.3 and 2.1.2. 4. See 2.1.3. 5. Used only when the message issued to indicate that a test or an exercise is taking place. When the word “TEST” or the abbreviation “EXER” is included, the message may contain information that should not be used operationally or will otherwise end immediately after the word "TEST". [Applicable 7November 2019] 6. In accordance with 1.1.4 and 2.1.4. 7. In accordance with 4.2.1 a). 8. In accordance with 4.2.4. 9. In accordance with 4.2.1 b). 10. In accordance with 4.2.2. 11. In accordance with 4.2.3. 12. Used for unnamed tropical cyclones. 13. In accordance with 4.2.5 and 4.2.6. 14. In accordance with 4.2.7. 15. In accordance with 4.2.8. 16. In accordance with 2.1.4. 17. In accordance with 4.2.1 c). 18. In accordance with 4.2.1 d). 19. The use of cumulonimbus (CB) and towering cumulus (TCU) is restricted to AIRMETs in accordance with 2.1.4. 20. In the case of volcanic ash cloud covering more than one area within the FIR, these elements can be repeated, as necessary. Each location and forecast position is to be preceded by an observed or forecast time. 21. In the case of cumulonimbus clouds associated with a tropical cyclone covering more than one area within the FIR, these elements can be repeated as necessary. Each location and forecast position must be preceded by an observed or forecast time. 22. A straight line is to be used between two points drawn on a map in the Mercator projection or between two points which crosses lines of longitude at a Constant angle. 23. The number of coordinates are to be kept to a minimum and should not normally exceed seven 24. Only for SIGMET messages for tropical cyclones. 25. Only for SIGMET messages for radioactive cloud. A radius of up to 30 kilometres (or 16 nautical miles) from the source and a vertical extent from surface (SFC) to the upper limit of the flight information region/upper flight information region (FIR/UIR) or control area (CTA) is to be applied. [Applicable 5 November 2020] 26. The elements “forecast time” and “forecast position” are not to be used in conjunction with the element “movement or expected movement”. 2627. The levels of the phenomena remain fixed throughout the forecast period. 28. Only for SIGMET messages for volcanic ash. 29. To be used for more than one volcanic ash clouds or cumulonimbus clouds associated with a tropical cyclone simultaneously affecting the FIR concerned. 30. End of the message (as the SIGMET/AIRMET message is being cancelled). The term CB is to be used when the forecast position for the cumulonimbus cloud is included. The forecast position for cumulonimbus (CB) cloud occurring in connection with tropical cyclones relate to the forecast time of the tropical cyclone centre position, not to the end of the validity period of the SIGMET message. For SIGMET messages for radioactive cloud, only within (WI) is to be used for the elements “location” and “forecast position”. For SIGMET messages for radioactive cloud, only stationary (STNR) is to be used for the element “movement or expected movement”. Table A6-1B. Template for special air-reports (uplink) Key: M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable; = = a double line indicates that the text following it should be placed on the subsequent line. Note.— The ranges and resolutions for the numerical elements included in special air-reports areshown in Table A6-4 of this appendix. Element Detailed content Template1,2 Examples Identification (M) Message identification ARS ARS Aircraft identification (M) Aircraft radiotelephony call nnnnnn VA8123 signObserved phenomenon Description of observed TS TS (M) phenomenon causing the TSGR TSGR issuance of the special air-report4 SEV TURB SEV TURB SEV ICE SEV ICE SEV MTW SEV MTW HVY DS HVY DS HVY SS HVY SS VA CLD VA CLD VA [MT nnnnnnnnnn] VA VA MT ASHVAL5 MOD TURB MOD ICE MOD TURB MOD ICE Observation time (M) Time of observation of OBS AT nnnnZ OBS AT 1210Z observed phenomenon Observed Location (C) Location (referring to NnnnnWnnnnn or N2020W07005 latitude and longitude (in NnnnnEnnnnn or S4812E01036 degrees and minutes)) of SnnnnWnnnnn or observed phenomenon SnnnnEnnnnn Observed Level (C) Flight level or altitude of FLnnn or FL390 observed phenomenon FLnnn/nnn or FL180/210 nnnnM (or [n]nnnnFT) 3000M 12000FT . . . Table A6-2. Template for aerodrome warning Key: M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable. Note 1.— The ranges and resolutions for the numerical elements included in aerodrome warnings are shown in Table A6-4 of this appendix. Note 2.— The explanations for the abbreviations can be found in the Procedures for Air Navigation Services — ICAO Abbreviations and Codes (PANS-ABC, Doc 8400). Element Detailed content Template(s) Examples YUC Location indicator of the Locationindicator of the aerodrome nnnn C aerodrome (M) Identification of the type of Type of message and sequence number AD WRNG [n]n AD WRNG 2 message (M) Validity period (M) Day and time of validity period in UTC VALID nnnnnn/nnnnnn VALID 211230/211530 IF THE AERODROME WARNING IS TO BE CANCELLED, SEE DETAILS AT THE END OF THE TEMPLATE. Description of phenomenon causing the TC3 nnnnnnnnnn or TC ANDREW Phenomenon (M)2 issuance of theaerodrome warning [HVY] TS or HVY SN 25CM GR or SFC WSPD 20MPS MAX 30 [HVY] SN [nnCM]3 or VA [HVY] FZRA or[HVY] FZDZ or RIME4 or TSUNAMI [HVY] SS or [HVY] DS or SA or DU or SFC WSPD nn[n]MPS MAX nn[n] (SFC WSPD nn[n]KT MAX nn[n]) or SFC WIND nnn/nn[n]MPS MAX nn[n] (SFC WIND nnn/nn[n]KT MAX nn[n]) or SQ or FROST or TSUNAMI or VA[DEPO] or TOX CHEM or Free text up to 32 charact Observed or forecast Indication whether the information is OBS [AT nnnnZ] or OBS AT 1200Z phenomenon (M) observed and expected to continue, or FCST OBS forecast Changes in intensity (C) Expected changes in intensity INTSF or WKN WKN or NC or 6 Cancellation of aerodrome Cancellation of aerodrome warning CNL AD WRNG [n]n nnnnnn/nnnnnn CNL AD WRNG 2 211230/211530 warn ing referring to its identification Notes.— 1. Fictitious location. 2. One phenomenon or a combination thereof, in accordance with 5.1.3. 3. In accordance with 5.1.3. 4. Hoar frost or rime in accordance with 5.1.3. 5. In accordance with 5.1.4. 6. End of the message (as the aerodrome warning is being cancelled).Table A6-3. Template for wind shear warning Key: M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable. Note 1.— The ranges and resolutions for the numerical elements included in wind shear warnings are shown in Table A6-4 of this appendix. Note 2.— The explanations for the abbreviations can be found in the PANS-ABC, Doc 8400. Element Detailed content Template(s) Examples YUC Location indicator of the Location indicator of the aerodrome nnnn C aerodrome (M) Identification of the type of Type of message and sequence WS WRNG [n]n WS WRNG 1 message (M) number Timeof originandvalidity period (M) Day andtime of issue and, where nnnnnn [VALID TL nnnnnn] or 211230 VALID TL 211330 applicable, validity period in UTC [VALID nnnnnn/nnnnnn] 221200 VALID 221215/221315 IF THE WIND SHEAR WARNING IS TO BE CANCELLED, SEE DETAILS AT THE END OF THE TEMPLATE. Phenomenon (M) Identification of the phenomenon and [MOD] or [SEV] WS IN APCH or WS APCH RWY12 its location [MOD] or [SEV] WS [APCH] RWYnnn MOD WS RWY34 or [MOD] or [SEV] WS IN CLIMB-OUT WS IN CLIMB-OUT or [MOD] or [SEV] WS CLIMB-OUT RWYnnn or MBST IN APCH or MBST APCH RWY26 MBST [APCH] RWYnnn or MBST IN CLIMB-OUT or MBST CLIMB-OUT RWYnnn MBST IN CLIMB-OUT Observed, reported or forecast Identification whether the REP AT nnnn nnnnnnnn or REP AT 1510 B747 phenomenon (M) phenomenon is observed or reported OBS [AT nnnn] or OBS AT 1205 and expected to continue or forecast FCST FCST Details of the phenomenon Description of phenomenon causing SFCWIND: nnn/nnMPS (or nnn/nnKT) nnnM SFC WIND: 320/5MPS (C) the issuance of the wind shear (nnnFT)-WIND: nnn/nnMPS (or nnn/nnKT) 60M-WIND: 360/13MPS warning (SFC WIND: 320/10KT or 200FT-WIND: 360/26KT) nnKMH (or nnKT) LOSS nnKM (or nnNM) 60KMH LOSS 4KM FNA RWYnn FNA RWY13 (30KT LOSS 2NM or FNA RWY13) nnKMH (or nnKT) GAIN nnKM (or nnNM) FNA RWYnn Or Cancellation of windshear warning3 Cancellation of wind shear warning CNL WS WRNG [n]n nnnnnn/nnnnnn CNL WS WRNG 1 211230/2113303 referring to its identification Notes.— 1. Fictitious location. 2. Additional provisions in 6.2.3. 3. End of the message (as the wind shear warning is being cancelled).Table A6-4. Ranges and resolutions for the numerical elements included in volcanic ash and tropical cyclone advisory messages, SIGMET messages and aerodrome and wind shear warnings Element as specified in Appendices 2 and 6 Range Resolution Summit elevation: M 000 – 8 100 1 FT 000 – 27 000 1 Advisory number: for VA (index)* 000 – 2 000 1 for TC (index)* 00 – 99 1 Maximum surface wind: MPS 00 – 99 1 KT 00 – 199 1 Central pressure: hPa 850 – 1 050 1 Surface wind speed: MPS 15 – 49 1 KT 30 – 99 1 Surface visibility: M 0000 – 0750 50 M 0800 – 5 000 100 Cloud: height of base: M 000 – 300 30 FT 000 – 1 000 100 Cloud: height of top: M 000 – 2 970 30 M 3 000 – 20 000 300 FT 000 – 9 900 100 FT 10 000 – 60 000 1 000 Latitudes: ° (degrees) 00 – 90 1 ΄ (minutes) 00 – 60 1 Longitudes: ° (degrees) 000 – 180 1 ΄ (minutes) 00 – 60 1 Flight levels: 000 – 650 10 Movement: KMH 0 – 300 10 KT 0 – 150 5 * Non-dimensional Example A6-1: SIGMET message and the corresponding cancellations SIGMET YUDD SIGMET 2 VALID 101200/101600 YUSO – YUDD SHANLON FIR/UIR OBSC TS FCST S OF N54 AND E OF W012 TOP FL390 MOV E 20KT WKN Cancellation of SIGMET YUDD SIGMET 3 VALID 101345/101600 YUSO – YUDD SHANLON FIR/UIR CNL SIGMET 2 101200/101600Example A6-1: SIGMET message for Tropical cyclone YUCC SIGMET 3 VALID 251600/252200 YUDO – YUCC AMSWELL FIR TC GLORIA OBS AT 1600Z N2706 W07306 CB TOP FL500 WI 150NM OF CENTRE MOV NW 10KT NC FCST 2200Z TC CENTRE N2740 W07345 Meaning: The third SIGMET message issued for the AMSWELL* flight information region (identified by YUCC Amswell area control centre) by the Donlon/International* meteorological watch office (YUDO) since 0001 UTC; the message is valid from 1600 UTC to 2200 UTC on the 25th of the month; tropical cyclone Gloria was observed at 1600 UTC at 27 degrees 6 minutes north and 73 degrees 6 minutes west with cumulonimbus top at flight level 500 within 150 nautical miles of the centre; the tropical cyclone is expected to move northwestwards at 10 knots and not to undergo any changes in intensity; the forecast position of the centre of the tropical cyclone at 2200 UTC is expected to be at 27 degrees 40 minutes north and 73 degrees 45 minutes west. Example A6-3. SIGMET message for volcanic ash Intentionally left blank Example A6-4. SIGMET message for radioactive cloud YUCC SIGMET 2 VALID 201200/201600 YUDO – YUCC AMSWELL FIR RDOACT CLD OBS AT 1155Z WI 3OKM OF N6030 E02550 SFC/FL550 STNR Meaning: The second SIGMET message issued for the AMSWELL* flight information region (identified by YUCC Amswell area control centre) by the Donlon/International* meteorological watch office (YUDO) since 0001 UTC; the message is valid from 1200 UTC to 1600 UTC on the 20th of the month; radioactive cloud was observed at 1155 UTC within 30 kilometres of 60 degrees 30 minutes north 25 degrees 50 minutes east between the surface and flight level 550. The radioactive cloud is stationary. * Fictitious locationExample A6-5. SIGMET message for severe turbulence YUCC SIGMET 5 VALID 221215/221600 YUDO – YUCC AMSWELL FIR SEV TURB OBS AT 1210Z N2020 W07005 FL250 INTSF FCST AT 1600Z S OF N2020 AND E OF W06950 Meaning: The fifth SIGMET message issued for the AMSWELL* flight information region (identified by YUCC Amswell area control centre) by the Donlon/International* meteorological watch office (YUDO) since 0001 UTC; the message is valid from 1215 UTC to 1600 UTC on the 22nd of the month; severe turbulence was observed at 1210 UTC 20 degrees 20 minutes north and 70 degrees 5 minutes west at flight level 250; the turbulence is expected to strengthen in intensity; at 1600 UTC the severe turbulence is forecast to be located south of 20 degrees 20 minutes north and east of 69 degrees 50 minutes west. * Fictitious locations Example A6-6. AIRMET message for moderate mountain wave Intentionally left blankAPPENDIX 7. TECHNICAL SPECIFICATIONS RELATED TO AERONAUTICAL CLIMATOLOGICAL INFORMATION (See Para 8 of this CAR) 1 Processing of Aeronautical Climatological Information Meteorological observations for regular and alternate aerodromes should be collected, processed and stored in a form suitable for the preparation of aerodrome climatological information. 2 Exchange of Aeronautical Climatological Information Aeronautical climatological information should be exchanged on request between meteorological authorities. Operators and other aeronautical users desiring such information should normally apply to the meteorological authority responsible for its preparation. 3 Content of Aeronautical Climatological Information 3.1 Aerodrome climatological tables 3.1.1 An aerodrome climatological table should give as applicable: a) mean values and variations therefrom, including maximum and minimum values, of meteorological elements (for example, of air temperature); and/or b) the frequency of occurrence of present weather phenomena affecting flight operations at the aerodrome (for example, of sandstorms); and/or c) the frequency of occurrence of specified values of one, or of a combination of two or more, elements (for example, of a combination of low visibility and low cloud). 3.1.2 Aerodrome climatological tables should include information required for the preparation of aerodrome climatological summaries in accordance with 3.2. 3.2 Aerodrome climatological summaries Aerodrome climatological summaries should cover: a) frequencies of the occurrence of runway visual range/visibility and/or height of the base of the lowest cloud layer of BKN or OVC extent below specified values at specified times; b) frequencies of visibility below specified values at specified times; c) frequencies of the height of the base of the lowest cloud layer of BKN or OVC extent below specified values at specified times; d) frequencies of occurrence of concurrent wind direction and speed within specified ranges; e) frequencies of surface temperature in specified ranges of 5°C atspecified times; and f) mean values and variations therefrom, including maximum and minimum values of meteorological elements required for operational planning purposes, including take- off performance calculations. Note.— Models of climatological summaries related to a) to e) are given in Technical Regulations WMO No. 49, Volume II — Meteorological Service for International Air Navigation, Part III.APPENDIX 8. TECHNICAL SPECIFICATIONS RELATED TO SERVICE FOR OPERATORS AND FLIGHT CREW MEMBERS (See Para 9 of this CAR) Note.— Specifications related to flight documentation (including the model charts and forms) are given in Appendix 1. 1 Means of supply and format of Meteorological Information 1.1 Meteorological information shall be supplied to operators and flight crew members by one or more of the following, as agreed between the meteorological authority and the operator concerned, and with the order shown below not implying priorities: a) written or printed material, including specified charts and forms; b) data in digital form; c) briefing; d) consultation; e) display; or f) in lieu of a) to e), by means of an automated pre-flight information system providing self-briefing and flight documentation facilities while retaining access by operators and aircrew members to consultation, as necessary, with the aerodrome meteorological office, in accordance with 5.1. 1.2 The meteorological authority, in consultation with the operator, shall determine: a) the type and format of meteorological information to be supplied; and b) methods and means of supplying that information. 1.3 On request by the operator, the meteorological information supplied for flight planning should include data for the determination of the lowest usable flight level. 2 Specifications related to information for Pre-flight planning and In-flight Re-planning 2.1 Format of upper-air gridded information Upper-air gridded information supplied by WAFCs for pre-flight and in-flight re- planning shall be in the GRIB code form. Note.— The GRIB code form is contained in Manual on Codes WMO No. 306, Volume I.2, Part B — Binary Codes. 2.2 Format of information on significant weather 2.2.1 Information on significant weather supplied by WAFCs for pre-flight p l a n n i n g and in-flight re- planning shall be in the BUFR code form. Note.— The BUFR code form is contained in Manual on Codes WMO No. 306, Volume I.2, Part B — Binary Codes.2.2.2 Recommendation. — As of 4 November 2021, in addition to 2.2.1, information on significant weather supplied by WAFCs for pre-flight planning and in-flight re planning should be in IWXXM GML form. Note 1. — Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). Note 2. — Geography markup language (GML) is an encoding standard of the Open Geospatial Consortium (OGC). 2.3 Specific needs of helicopter operations Meteorological information for pre-flight planning and in-flight re- planning by operators of helicopters flying to offshore structures should include data covering the layers from sea level to flight level 100. Particular mention should be made of the expected surface visibility, the amount, type (where available), base and tops of cloud below flight level 100, sea state and sea-surface temperature, mean sea-level pressure, and the occurrence and expected occurrence of turbulence and icing, as determined by regional air navigation agreement. 3 Specifications related to briefing and consultation 3.1 Information required to be displayed The material displayed shall be readily accessible to the flight crew members or other flight operations personnel concerned. 4 Specifications related to information flight documentation 4.1 Presentation of information 4.1.1 The flight documentation related to forecasts of upper wind and upper-air temperature and SIGWX phenomena shall be presented in the form of charts. Note.— Models of charts and forms for use in the preparation of flight documentation are given in Appendix 1. These models and methods for their completion are developed by the WMO on the basis of relevant operational requirements stated by ICAO. 4.1.2 The flight documentation related to concatenated route-specific upper wind and upper-air temperature forecasts should be provided as agreed between the meteorological authority and the operator concerned. Note.— Guidance on the design, formulation and use of concatenated charts is given in the Manual of Aeronautical Meteorological Practice (Doc 8896). 4.1.3 METAR and SPECI (including trend forecasts as issued in accordance with regional air navigation agreement), TAF, SIGMET and tropical cyclone advisory information shall be presented in accordance with the templates in Appendices 1, 2, 3, 5 and 6. Such meteorological information received from other meteorological offices shall be included in flight documentation without change. Note.— Examples of the form of presentation of METAR/SPECI and TAF are given in Appendix 1.4.1.4 The location indicators and the abbreviations used should be explained in the flight documentation. 4.1.5 The forms and the legend of charts included in flight documentation should be printed in English, French, Russian or Spanish. Where appropriate, approved abbreviations should be used. The units employed for each element should be indicated; they should be in accordance with Annex 5. 4.2 Charts in flight documentation 4.2.1 Characteristics of charts 4.2.1.1 Charts included in flight documentation should have a high standard of clarity and legibility and should have the following physical characteristics: a) for convenience, the largest size of charts should be about 42 × 30 cm (standard size A3) and the smallest size should be about 21 × 30 cm (standard size A4). The choice between these sizes should depend on the route lengths and the amount of detail that needs to be given in the charts as agreed between meteorological authority and users concerned; b) major geographical features, such as coastlines, major rivers and lakes should be depicted in a way that makes them easily recognizable; c) for charts prepared by computer, meteorological data should take preference over basic chart information, the former cancelling the latter wherever they overlap; d) major aerodromes should be shown as a dot and identified by the first letter of the name of the city the aerodrome serves as given in Table AOP of the relevant regional air navigation plan; e) a geographical grid should be shown with meridians and parallels represented by dotted lines at each 10° latitude and longitude; dots should be spaced one degree apart; f) latitude and longitude values should be indicated at various points throughout the charts (i.e. not only at the edges); and g) labels on the charts for flight documentation should be clear and simple and should present the name of the world area forecast centre (WAFC) or, for non- world area forecast system (WAFS) products, the originating centre, the type of chart, date and valid time and, if necessary, the types of units used in an unambiguous way. Note.— When plotting shapes, particularly polygons, on maps, appropriate corrections are necessary if plotted on projections different to that used in the production of the original forecast area. 4.2.1.2 Meteorological information included in flight documentation shall be represented as follows: a) winds on charts shall be depicted by arrows with feathers and shaded pennants on a sufficiently dense grid; b) temperatures shall be depicted by figures on a sufficiently dense grid; c) wind and temperature data selected from the data sets received from a world area forecast centre shall be depicted in a sufficiently dense latitude/longitude grid; andd) wind arrows shall take precedence over temperatures and either shall take precedence over chart background. 4.2.1.3 For short-haul flights, charts should be prepared covering limited areas at a scale of 1:15 × 106 as required. 4.2.2 Set of charts to be provided 4.2.2.1 The minimum number of charts for flights between flight level 250 and flight level 630 shall include a high-level SIGWX chart (flight level 250 to flight level 630) and a forecast 250 hPa wind and temperature chart. The actual charts Provided for pre-flight and in-flight planning and for flight documentation shall be as agreed between meteorological authorities and users concerned. 4.2.2.2 Charts to be provided shall be generated from the digital forecast provided by the WAFCs whenever these forecasts cover the intended flight path in respect of time, altitude and geographical extent, unless otherwise agreed between the meteorological authority and the operator concerned. 4.2.3 Height indications In flight documentation, height indications shall be given as follows: a) all references to en-route meteorological conditions, such as height indications of upper winds, turbulence or bases and tops of clouds, shall preferably be expressed in flight levels; they may also be expressed in pressure, altitude or, for low-level flights, height above ground level; and b) all references to aerodrome meteorological conditions, such as height indications of the bases of clouds, shall be expressed in height above the aerodrome elevation. 4.3 Specifications related to low-level flights 4.3.1 In chart form Where the forecasts are supplied in chart form, flight documentation for low- level flights, including those in accordance with the visual flight rules, operating up to flight level 100 (or up to flight level 150 in mountainous areas or higher, where necessary), should contain the following as appropriate to the flight: a) information from relevant SIGMET messages; b) upper wind and upper-air temperature charts as given in Appendix 5, 4.3.1; and c) significant weather charts as given in Appendix 5, 4.3.2. 4.3.2 In abbreviated plain language Where the forecasts are not supplied in chart form, flight documentation for low-level flights, including those in accordance with the visual flight rules, operating up to flight level 100 (up to flight level 150 in mountainous areas or higher, where necessary), should contain the following information as appropriate to the flight:a) SIGMET information; and b) GAMET area forecasts. Note.— An example of the GAMET area forecast is given in Appendix 5. 5 Specifications related to automated pre-flight information system for briefing, consultation, flight planning and flight documentation 5.1 Access to the systems Automated pre-flight information systems providing self-briefing facilities shall provide for access by operators and flight crew members to consultation, as necessary, with an aerodrome meteorological office by telephone or other suitable telecommunications means. 5.2 Detailed specifications of the systems Automated pre-flight information systems for the supply of meteorological information for self-briefing, pre-flight planning and flight documentation should: a) provide for the continuous and timely updating of the system database and monitoring of the validity and integrity of the meteorological information stored; b) permit access to the system by operators and flight crew members and also by other aeronautical users concerned through suitable telecommunications means; c) use access and interrogation procedures based on abbreviated plain language and, as appropriate, ICAO location indicators, and aeronautical meteorological code data-type designators prescribed by the WMO, or based on a menu-driven user interface, or other appropriate mechanisms as agreed between the meteorological authority and operators concerned; and d) provide for rapid response to a user request for information. Note.— ICAO abbreviations and codes and location indicators are given respectively in the Procedures for Air Navigation Services — ICAO Abbreviations and Codes (PANS- ABC, Doc 8400) and Location Indicators (Doc 7910). Aeronautical meteorological code data-type designators are given in the Manual on the Global Telecommunication System (WMO No. 386). 6 Specifications related to Information for aircraft in flight 6.1 Supply of information requested by an aircraft in flight If an aircraft in flight requests meteorological information, the aerodrome meteorological office or meteorological watch office which receives the request should arrange to supply the information with the assistance, if necessary, of another aerodrome meteorological office or meteorological watch office. 6.2 Information for in-flight planning by the operatorMeteorological information for planning by the operator for aircraft in flight should be supplied during the period of the flight and should normally consist of any or all of the following: a) METAR and SPECI (including trend forecasts as issued in accordance with regional air navigation agreement); b) TAF and amended TAF; c) SIGMET relevant to the flight, unless the latter have been the subject of a SIGMET message; d) upper wind and upper-air temperature information; e) volcanic ash and tropical cyclone advisory information relevant to the flight; and f) other meteorological information in alphanumeric or graphical form as agreed between the meteorological authority and the operator concerned. Note.— Guidance on the display of graphical information in the cockpit is provided in the Manual of Aeronautical Practice (Doc 8896). CHART LATITUDE LONGITUDE CHART LATITUDE LONGITUDE A N6700 W13724 D N6300 W01500 A N6700 W01236 D N6300 E13200 A S5400 W01236 D S2700 E13200 A S5400 W13724 D S2700 W01500 ASIA N3600 E05300 E N4455 E02446 ASIA N3600 E10800 E N4455 E18000 ASIA 0000 E10800 E S5355 E18000 ASIA 0000 E05300 E S5355 E02446 B N0304 W13557 F N5000 E10000 B N7644 W01545 F N5000 W11000 B N3707 E06732 F S5242 W11000 B S6217 W05240 F S5242 E10000 B1 N6242 W12500 M N7000 E10000 B1 N6242 E04000 M N7000 W11000 B1 S4530 E04000 M S1000 W11000B1 S4530 W12500 M S1000 E10000 C N7500 W03500 MID N4400 E01700 C N7500 E07000 MID N4400 E07000 C S4500 E07000 MID N1000 E07000 C S4500 W03500 MID N1000 E01700 Figure A8-1: Fixed areas of coverage of WAFS forecasts in chart form — Mercator projection CHART LATITUDE LONGITUDE CHART LATITUDE LONGITUDE EUR N4633 W05634 I N1912 E11130 EUR N5842 E06824 I N3330 W06012 EUR N2621 E03325 I N0126 W12327 EUR N2123 W02136 I S0647 E16601 G N3552 W02822 L N1205 E11449 G N1341 E15711 L N1518 E04500 G S0916 E10651 L N2020 W06900 G S0048 E03447 L N1413 W14338 H N3127 W14836 NAT N4439 W10143 H N2411 E05645 NAT N5042 E06017 H S0127 W00651 NAT N1938 E00957 H N0133 W07902 NAT N1711 W05406 Figure A8-2: Fixed areas of coverage of WAFS forecasts in chart form — Polar stereographic projection (northern hemisphere)CHART LATITUDE LONGITUDE J S0318 W17812 J N0037 W10032 J S2000 W03400 J S2806 E10717 K N1255 E05549 K N0642 E12905 K S2744 W16841 K S1105 E00317 Figure A8-3: Fixed areas of coverage of WAFS forecasts in chart form — Polar stereographic projection (southern hemisphere)APPENDIX 9. TECHNICAL SPECIFICATIONS RELATED TO INFORMATION FOR AIR TRAFFIC SERVICE, SEARCH AND RESCUE SERVICE AND AERONAUTICAL INFORMATION SERVICES (See Para 10 of this CAR) 1 Information to be provided for Air Traffic Services Units 1.1 List of information for the aerodrome control tower The following meteorological information shall be supplied, as necessary, to an aerodrome control tower by its associated aerodrome meteorological office: a) local routine reports, local special reports, METAR, SPECI, TAF, trend forecasts and amendments thereto, for the aerodrome concerned; b) SIGMET information, wind shear warnings and alerts and aerodrome warnings; c) any additional meteorological information agreed upon locally, such as forecasts of surface wind for the determination of possible runway changes; d) information received on volcanic ash cloud, for which a SIGMET has not already been issued; and e) information received on pre-eruption volcanic activity and/or a volcanic eruption as agreed between the meteorological and ATS authorities concerned. 1.2 List of information for the approach control unit The following meteorological information shall be supplied, as necessary, to an approach control unit by its associated aerodrome meteorological office: a) local routine reports, local special reports, METAR, SPECI, TAF, trend forecasts and amendments thereto, for the aerodrome(s) with which the approach control unit is concerned; b) SIGMET information, wind shear warnings and alerts for the airspace with which the approach control unit is concerned and aerodrome warning c) s; d) any additional meteorological information agreed upon locally; e) information received on volcanic ash cloud, for which a SIGMET has not already been issued, as agreed between the meteorological and ATS authorities concerned; and f) information received on pre-eruption volcanic activity and/or a volcanic eruption as agreed between the meteorological and ATS authorities concerned. 1.3 List of information for the area control centre (ACC) and flight information centre (FIC) The following meteorological information shall be supplied, as necessary, to an area control centre (ACC) or a flight information centre (FIC) by itsassociated meteorological watch office: a) METAR and SPECI, including current pressure data for aerodromes and other locations, TAF and trend forecasts and amendments thereto, covering the flight information region ( F I R ) or the control area ( C T A ) and, if required by the flight information centre (FIC) or area control centre (ACC), covering aerodromes in neighbouring FIRs, as determined by regional air navigation agreement; b) forecasts of upper winds, upper-air temperatures and significant en-route weather phenomena and amendments thereto, particularly those which are likely to make operation under visual flight rules impracticable, SIGMET information and appropriate special air-reports for the FIR or CTA and, if determined by regional air navigation agreement and required by the FIC or ACC, for neighbouring FIRs; c) any other meteorological information required by the FIC or ACC to meet requests from aircraft in flight; if the information requested is not available in the associated MWO, that office shall request the assistance of another meteorological office in supplying it; d) information received on volcanic ash cloud, for which a SIGMET has not already been issued as agreed between the meteorological and ATS authorities concerned; e) information received concerning the release of radioactive materials into the atmosphere as agreed between the meteorological and ATS authorities concerned; f) tropical cyclone advisory information issued by a TCAC in its area of responsibility; g) volcanic ash advisory information issued by a VAAC in its area of responsibility; and h) information received on pre-eruption volcanic activity and/or a volcanic eruption. 1.4 Supply of information to aeronautical telecommunications stations Where necessary for flight information purposes, current meteorological reports and forecasts shall be supplied to designated aeronautical telecommunication stations. A copy of such information shall be forwarded, if required, to the FIC or ACC. 1.5 Format of information 1.5.1 Local routine report, local secial reports, METAR, SPECI, TAF, trend forecasts, SIGMET information, upper wind and upper-air temperature forecasts and amendments thereto should be supplied to air traffic services units in the form in which they are prepared, disseminated to other aerodrome meteorological offices or MWOs or received from other aerodrome meteorological offices or MWOs, unless otherwise agreed locally. 1.5.2 When computer-processed upper-air data for grid points are made available to air traffic services units in digital form for use by air traffic services computers, the contents, format and transmission arrangements should be as agreed between the meteorological authority and the appropriate ATS authority. The data should normally be supplied as soonas is practicable after the processing of the forecasts has been completed. 2 Information to be provided for Search and Rescue Service Units 2.1 List of information Information to be supplied to rescue coordination centres shall include the meteorological conditions that existed in the last known position of a missing aircraft and along the intended route of that aircraft with particular reference to: a) significant en-route weather phenomena; b) cloud amount and type, particularly cumulonimbus; height indications of bases and tops; c) visibility and phenomena reducing visibility; d) surface wind and upper wind; e) state of ground, in particular, any snow cover or flooding; f) sea-surface temperature, state of the sea, ice cover if any and ocean currents, if relevant to the search area; and g) sea-level pressure data. 2.2 Information to be provided on request 2.2.1 On request from the rescue coordination centre, the designated aerodrome meteorological office or MWO should arrange to obtain details of the flight documentation which was supplied to the missing aircraft, together with any amendments to the forecast which were transmitted to the aircraft in flight. 2.2.2 To facilitate search and rescue operations, the designated aerodrome meteorological office or MWO should, on request, supply: a) complete and detailed information on the current and forecast meteorological conditions in the search area; and b) current and forecast conditions en route, covering flights by search aircraft from and returning to the aerodrome from which the search is being conducted. 2.2.3 On request from the rescue coordination centre, the designated aerodrome meteorological office or MWO should supply or arrange for the supply of meteorological information required by ships undertaking search and rescue operations. 3 Information to be provided for Aeronautical Information Service Units 3.1 List of information The following information shall be supplied, as necessary, to an aeronautical information services unit: a) information on meteorological service for international air navigation, intended for inclusion in the aeronautical information publication(s) concerned; Note.— Details of this information are given in PANS-AIM, Appendix 3, Part 1, GEN 3.5 and Part 3, AD 2.2, 2.11, 3.2 and 3.11.b) information necessary for the preparation of NOTAM or ASHTAM including, in particular, information on: 1) the establishment, withdrawal and significant changes in operation of aeronautical meteorological services. This information is required to be provided to the aeronautical information services unit sufficiently in advance of the effective date to permit issuance of NOTAM in compliance with Annex 15, 3.2.2 and 3.2.3; 2) the occurrence of volcanic activity; and Note.— The specific information required is given in Para 3, 3.3.2 and Para 4, 4.8 of this CAR. 3) release of radioactive materials into the atmosphere as agreed between the meteorological and appropriate civil aviation authorities concerned; and Note.— The specific information required is given in Para 3, 3.4.2 g) of this CAR. c) information necessary for the preparation of aeronautical information circulars including, in particular, information on: 1) expected important changes in aeronautical meteorological procedures, services and facilities provided; and 2) effect of certain weather phenomena on aircraft operations.APPENDIX 10. TECHNICAL SPECIFICATIONS RELATED TO REQUIREMENTS FOR AND USE OF COMMUNICATIONS (See Para 11 of this CAR) 1 Specific requirements for communication 1.1 Required transit times of operational meteorological information Messages and bulletins containing operational meteorological information shall achieve transit times of less than 5 minutes, unless otherwisedetermined to be lower by regional air navigation agreement. 1.2 Grid point data for ATS and operators 1.2.1 When upper-air data for grid points in digital form are made available for use by air traffic services computers, the transmission arrangements should be as agreed between the meteorological authority and the appropriate ATS authority. 1.2.2 When upper-air data for grid points in digital form are made available to operators for flight planning by computer, the transmission arrangements should be as agreed among the WAFC concerned, the meteorological authority and the operators concerned. 2 Use of Aeronautical Fixed Service Communications and Public Internet 2.1 Meteorological bulletins in alphanumeric format 2.1.1 Composition of bulletins Whenever possible, exchanges of operational meteorological information should be made in consolidated bulletins of the same types of meteorological information. 2.1.2 Filing times of bulletins Meteorological bulletins required for scheduled transmissions should be filed regularly and at the prescribed scheduled times. METAR should be filed for transmission not later than 5 minutes after the actual time of observation. TAF should be filed for transmission not earlier than one hour prior to the beginning of their validity period. 2.1.3 Heading of bulletins Meteorological bulletins containing operational meteorological information to be transmitted via the aeronautical fixed service or the public Internet shall contain a heading consisting of: a) an identifier of four letters and two figures; b) the ICAO four-letter location indicator corresponding to the geographical location of the meteorological office originating or compiling the meteorological bulletin;c) a day-time group; and d) if required, a three-letter indicator. Note 1.— Detailed specifications on format and contents of the heading are given in Manual on the Global Telecommunication System, WMO No. 386 and are reproduced in the Manual of Aeronautical Meteorological Practice (Doc 8896). Note 2.— ICAO location indicators are listed in Location Indicators (Doc 7910). 2.1.4 Transmission of bulletins containing operational meteorological information Meteorological bulletins containing operational meteorological information shall be transmitted via the aeronautical fixed service (AFS). 2.2 World area forecast system (WAFS) products 2.2.1 Telecommunications for the supply of WAFS products The telecommunications facilities used for the supply of WAFS productsshould be the aeronautical fixed service or the public Internet. 2.2.2 Quality requirements for charts Where WAFS products are disseminated in chart form, the quality of the charts received should be such as to permit reproduction in a sufficiently legible form for flight planning and documentation. Charts received should be legible over 95 per cent of their area. 2.2.3 Quality requirements for transmissions Transmissions should be such as to ensure that their interruption should not exceed 10 minutes during any period of 6 hours. 2.2.4 Heading of bulletins containing WAFS products Meteorological bulletins containing WAFS products in digital form to be transmitted via aeronautical fixed service or the public Internet shall contain a heading as given in 2.1.3. 3 Use of Aeronautical Mobile Service Communications 3.1 Content and format of meteorological messages 3.1.1 The content and format of reports, forecasts and SIGMET information transmitted to aircraft shall be consistent with the provisions of Para 4, 6 and 7 of this CAR. 3.1.2 The content and format of air-reports transmitted by aircraft shall be consistent with the provisions of Para 5 of this CAR and the Procedures for Air Navigation Services — Air Traffic Management (PANS-ATM, Doc 4444), Appendix 1. 3.2 Content and format of meteorological bulletins The substance of a meteorological bulletin transmitted via the aeronauticalmobile service shall remain unchanged from that contained in the bulletin as originated. 4 Intentionally left blank. 5 Use of Aeronautical Broadcasting Service — VOLMET Broadcasts 5.1 Detailed content of meteorological information to be included in VOLMET broadcasts 5.1.1 The aerodromes for which METAR, SPECI and TAF are to be included in VOLMET broadcasts, the sequence in which they are to be transmitted and the broadcast time shall be determined by regional air navigation agreement. 5.1.2 The flight information regions for which SIGMET messages are to be included in scheduled VOLMET broadcasts shall be determined by regional air navigation agreement. Where this is done, the SIGMET message shall be transmitted at the beginning of the broadcast or of a five-minute time block. 5.2 Criteria related to information to be included in VOLMET broadcasts 5.2.1 When a report has not arrived from an aerodrome in time for a broadcast, the latest available report should be included in the broadcast, together with the time of observation. 5.2.2 TAF included in scheduled VOLMET broadcasts should be amended as necessary to ensure that a forecast, when transmitted, reflects the latest opinion of the aerodrome meteorological office concerned. 5.2.3 Where SIGMET messages are included in scheduled VOLMET broadcasts, an indication of “NIL SIGMET” should be transmitted if no SIGMET message is valid for the FIRs concerned. 5.3 Format of information to be included in VOLMET broadcasts 5.3.1 The content and format of reports, forecasts and SIGMET information included in VOLMET broadcasts shall be consistent with the provisions of Para 4, 6 and 7 of this CAR. 5.3.2 VOLMET broadcasts should use standard radiotelephony phraseologies. Note.— Guidance on the standard radiotelephony phraseologies to be used in VOLMET broadcasts is given in the Manual on Coordination between Air Traffic Services, Aeronautical Information Services and Aeronautical Meteorological Services (Doc 9377), Appendix 1.ATTACHMENTS: ATTACHMENT A. OPERATIONALLY DESIRABLE ACCURACY OF MEASUREMENT OR OBSERVATION Note.— The guidance contained in this table relates to Para2, 2.2 — Supply, use, quality management and interpretation of meteorological information, in particular to 2.2.7, and Para 4 —Meteorological observations and reports. Operationally desirable accuracy Element to be observed of measurement or observation* Mean surface wind Direction: ± 10° Speed: ± 0.5 m/s (1 kt) up to 5 m/s (10 kt) ± 10% above 5 m/s (10 kt) Variations from the mean surface wind ± 1 m/s (2 kt), in terms of longitudinal and lateral components Visibility ± 50 m up to 600 m ± 10% between 600 m and 1 500 m ± 20% above 1 500 m Runway visual range ± 10 m up to 400 m ± 25 m between 400 m and 800 m ± 10% above 800 m Cloud amount ± 1 okta Cloud height ± 10 m (33 ft) up to 100 m (330 ft) ± 10% above 100 m (330 ft) Air temperature and dew-point temperature ± 1°C Pressure value (QNH, QFE) ± 0.5 hPa * The operationally desirable accuracy is not intended as an operational requirement; it is to be understood as a goal that has been expressed by the operators. Note.— Guidance on the uncertainties of measurement or observation can be found in the Guide to Meteorological Instruments and Methods of Observation (WMO- No.8).ATTACHMENT B: OPERATIONALLY DESIRABLE ACCURACY OF FORECASTS Note 1.— The guidance contained in this table relates to para 2, 2.2 — Supply, use, quality management and interpretation of meteorological information, in particular to 2.2.8, and Para 6 — Forecasts. Note 2.— If the accuracy of the forecasts remains within the operationally desirable range shown in the second column, for the percentage of cases indicated in the third column, the effect of forecast errors is not considered serious in comparison with the effects of navigational errors and of other operational uncertainties. Element to be Operationally Minimum forecast desirable percentage of accuracy of cases within range forecasts TAF Wind direction ± 20° 80% of cases Wind speed ± 2.5 m/s (5 kt) 80% of cases Visibility ± 200 m up to 800 m 80% of cases ± 30% between 800 m and 10 km Precipitation Occurrence or non-occurrence 80% of cases Cloud amount One category below 450 m (1 500 ft) 70% of cases Occurrence or non-occurrence of BKN or OVC between 450 m (1 500 ft) and 3 000 m (10 000 ft) Cloud height ± 30 m (100 ft) up to 300 m (1 000 ft) 70% of cases ± 30% between 300 m (1 000 ft) and 3 000 m (10 000 ft) Air temperature ± 1°C 70% of cases TREND FORECAST Wind direction ± 20° 90% of cases Wind speed ± 2.5 m/s (5 kt) 90% of cases Visibility ± 200 m up to 800 m 90% of cases ± 30% between 800 m and 10 km Precipitation Occurrence or non-occurrence 90% of cases ( Cloud amount One category below 450 m (1500 ft) 1 Occurrence or non-occurrence of BKN or OVC 0 between 450 m (1 500 ft) and 3000 m (10000 ft) 0 0 Cloud height ± 30 m (100 ft) up to 300 m (1000 ft)0 ± 30% between 300 m (1000 ft) and 3000 m ft) 90% of cases 90% of cases Element to be Operationally Minimum forecast desirable percentage ofaccuracy of cases within range forecasts FORECAST FOR TAKE-OFF Wind direction ± 20° 90% of cases Wind speed ± 2.5 m/s (5 kt) up to 12.5 m/s (25 kt) 90% of cases Air temperature ± 1°C 90% of cases Pressure value ± 1 hPa 90% of cases (QNH) AREA, FLIGHT AND ROUTE FORECASTS Upper-air ± 2°C (Mean for 900 km (500 NM) 90% of cases temperature Relative humidity ± 20% 90% of cases Upper wind ± 5 m/s (10 kt) 90% of cases (Modulus of vector difference for 900 km (500 NM) Significant en- Occurrence or non-occurrence 80% of cases route weather Location: ± 100 km (60 NM) 70% of cases phenomena and Vertical extent: ± 300 m (1 000 ft) 70% of cases cloud Flight level of tropopause: ± 300 m (1 000 ft) 80% of cases Max wind level: ± 300 m (1 000 ft) 80% of casesATTACHMENT C. SELECTED CRITERIA APPLICABLE TO AERODROME REPORTS (The guidance in this table relates to Para 4 and Appendix 3.) Runway visual range1 c Cloud A B C (OBS TIME) Present Pressure Supplementary Surface wind Visibility (VIS) –10 5 weather Amount Type2 Temperature (QNH, QFE) information (Time, MIN) Speed Directional variations3 variations3 Directional variations4 Past tendency5 Layers reported if coverage Specifications < 1≥ . 56 m0 M° / e sa an nd s< p 1 e8 e0 d ≥° 1.5 m/s ≥ 180° m ≥E x e 5c a me ne /sd sp i e (n 1eg 0d t kh b te y ) General rule M < i 1n i 5m <0 u 0 0m .m 5 V ×S p oI Sp rr ee vc aia ill i c n a gs Ve pIs rS eM f vlu ain c ili t im u ngaVu t Im ViS n IS gV cI aS an nd n ot R 5( AB) R 5(BC ) apN po l tic c h rg ai ee t b en Wlr ee ia X r t a ol all L lao yw ere st N > ext layer Nex lt a h yeig rh >e r C TCB U6 or Identification Pa rr ea pm oe rt te er ds U mchp a aad g gn ra negt itee e udd s d >i ef P t ia nor c a b lm ue d e et de r (3 kt) (3 kt) prevailing be determined < 100 m phenomena (for No criteria VIS specific criteria, see Appendix 3, Local 2 m/1 in0 7 2 m/1 in0 7 2 min 10 min 8 1 min 1 min 4.4.2) routineand N/A N/A Always 2/8 4/8 Always CB QNH Yes All11 s rp ee pc oi ra tl VRB + 2 mean + 2 Minimum and VIS TCU QFE10 extreme extreme VRB (no maximum along the N/A9 directions directions extremes) speed runway(s) 10 min 10 min 10 min 10 min 8 10 min 10 min Prevailing VIS and Recent WX M /E ST PA ER C I eV xtR rB em (n eo s ) em xe tra en m + e 2 eV xtR reB m (n eo s ) Ma sx pi em eu dm Prev Vai Il Sin g min +im du irm ec V tiI oS n Minimum VIS oN bso e rt ve en dd e (“n Nc ”y ) U o dr op ww na wrd a ( r“ dU ”) Always 2/8 4/8 Always TC CB U QNH No o sip ge nr ifao ictf i ao nn ca el directions (“D”) and wind No tendency available, shear12 the tendency is to be omitted Relevant Direction in three figures Speed in If Step applicable If Step applicable N/A If Step applicable Rounded In whole hPa15 rounded N/A reporting rounded to the 1 m/s to whole down for decimals 1 – 9 scales for all nearest 10 degrees or 1 kt VIS < 800 m : 50 m RVR < 400 m : 25 m400 m ≤ degrees: up messages 800 m ≤ VIS < 5 000 m : 100m RVR ≤ 800 m : 50m Base ≤ 3 000 m (10 000 ft) : 30 m (100 ft) for (degrees 1 – 4 down, Speed < 5 000 m ≤ VIS < 10 km : 1 km 800 m < RVR < 2 000 m : 100 m13 decimal 5 degrees 5 – 9 up) 0.5 m/s (1 kt) VIS ≥ 10 km : None, given as 10 km or (Reference level: Aerodrome elevation14 indicated as covered under CAVOK or mean sea level for offshore structures) CALM Rev. 2, 8th November 2018 154Notes-- 1. Considered for the past 10 minutes (exception: if the 10-minute period includes a marked discontinuity (i.e. runway visual range changes or passes 175, 300, 550 or 800 m, lasting ≥ 2 minutes), only data after the discontinuity to be used). A simple diagrammatic convention is used to illustrate those parts of the 10- minute period prior to the observation relevant to runway visual range criteria, i.e. AB, BC and AC. 2. Layer composed of CB and TCU with a common base should be reported as “CB”. 3. Considered for the past 10 minutes (exception: if the 10-minute period includes a marked discontinuity (i.e. the direction changes ≥ 30° with a speed ≥ 5 m/s or the speed changes ≥ 5 m/s lasting ≥ 2 minutes), only data after the discontinuity to be used). 4. If several directions, the most operationally significant direction used. 5. Let R 5(AB)= 5-minute mean runway visual range value during period AB and R 5(BC) = 5-minute mean runway visual range value during period BC. 6. CB (cumulonimbus) and TCU (towering cumulus = cumulus congestus of great vertical extent) if not already indicated as one of the other layers. 7. Time averaging, for mean values and, if applicable, referring period for extreme values, indicated in the upper left-hand corner. 8. According to the Manual on Codes (WMO-No. 306), Volume I.1, Part A — Alphanumeric Codes, paragraph 15.5.5, it is recommended that the wind measuring systems should be such that peak gusts should represent a three-second average”. 9. N/A = not applicable. 10. QFE is to be included if required. Reference elevation for QFE should be aerodrome elevation except for precision approach runways, and non-precision approach runways with threshold ≥ 2 m (7 ft) below or above aerodrome elevation, where the reference level should be the relevant threshold elevation. 11. As listed in Appendix 3, 4.8. 12. Also sea-surface temperature, and state of the sea or the significant wave height from offshore structures in accordance with regional air navigation agreement. 13. Report if RVR and/or VIS < 1 500 m, limits for assessments 50 and 2 000 m. 14. For landing at aerodromes with precision approach runways and with the threshold elevation ≥ 15 m below the aerodrome elevation, the threshold elevation to be used as a reference. 15. Measured in 0.1 hPaATTACHMENT D. CONVERSION OF INSTRUMENTED READING INTO RUNWAY VISUAL RANGE AND VISIBILITY (See Appendix 3, 4.3.5 of this CAR) 1 The conversion of instrumented readings into runway visual range and visibility is based on Koschmieder’s Law or Allard’s Law, depending on whether the pilot can be expected to obtain main visual guidance from the runway and its markings or from the runway lights. In the interest of standardization in runway visual range assessments, this Attachment provides guidance on the use and application of the main conversionfactors to be used in these computations. 2 In Koschmieder’s Law one of the factors to be taken into account is the pilot contrast threshold. The agreed constant to be used for this is 0.05 (dimensionless). 3 In Allard’s Law the corresponding factor is the illumination threshold. This is not a constant, but a continuous function dependent on the background luminance. Theagreed relationship to be used in instrumented systems with continuous adjustment of the illumination threshold by a background luminance sensor is shown by the curve in Figure D-1. The use of a continuous function which approximates the step function such as displayed in Figure D-1 is preferred, due to its higher accuracy, to the stepped relationship described in paragraph 4. 4 In instrumented systems without continuous adjustment of the illumination threshold, the use of four equally spaced illumination threshold values with agreed corresponding back- ground luminance ranges is convenient but will reduce accuracy. The four values are shown in Figure D-1 in the form of a step function; they are tabulated in Table D-1 for greater clarity. Note 1.— Information and guidance material on the runway lights to be used for assessment of runway visual range are contained in the Manual of Runway Visual Range Observing and Reporting Practices (Doc 9328). Note 2.— In accordance with the definition of visibility for aeronautical purposes, theintensity of lights to be used for the assessment of visibility is in the vicinity of 1 000 cd. Table D-1. Illumination threshold steps Illumination threshold Background Condition (lx) luminance (cd/m2) Night 8 × 10- ≤ 50 7 Intermediate 10-5 51 – 999 Rev. 2, 8th November 2018 156Normal day 10-4 1000 – 12000 Bright day (sunlit fog) 10-3 > 12000 Rev. 2, 8th November 2018 157ATTACHMENT E. SPATIAL RANGES AND RESOLUTIONS FOR SPACE WEATHERADVISORY INFORMATION The technical specifications related to SWXC are stipulates in Chapter 3, Appendix 2 and Attachment E of ICAO Annex 3 for the contracting states which have accepted responsibilities to monitor and provide advisory information on space weather. India is not a SWXC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with SWXC and use its services effectively. products/ Element to Range Resoluti be forecast on Flight level affected by radiation 250 – 600 310 Longitudes for advisories (degrees) 000 – 180 15 Latitudes for advisories (degrees) 00 – 90 10 … … … … (Vikram Dev Dutt) Director General of Civil Aviation Rev. 2, 8th November 2018 158