Regulation No: 2025/R-37 MCAR-3 Meteorological Service for Air Navigation

` Volume: 54 Issue: 70 Date: 19 Shawwal 1446 – 17 April 2025 Thursday Regulation No: 2025/R-37 MCAR-3 Meteorological Service for Air Navigation The President’s Office • For publication of regulations and Boduthakurufaanu Magu guidelines in the Gazette, send to Male, Maldives’ legalaffairs@po.gov.mv Phone: 3336211 Mobile: 7242885 Website: www.gazette.gov.mv Volume: 54 Issue No: 70 Regulation No: 2025/R-37 Government Gazette Maldives Civil Aviation Authority Republic of Maldives Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Issue 3.00, 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Foreword Foreword Maldives Civil Aviation Authority, in exercise of the powers conferred on it under Articles 5 and 6 of the Maldives Civil Aviation Authority Act 2/2012 has issued this Regulation. This Regulation shall be cited as MCAR-3 Meteorological Service for Air Navigation and shall come into force on 17th April 2025. This Regulation contains the standards, requirements and procedures pertaining to the provision of meteorological services. The standards and requirements in this Regulation are based mainly on standards and recommended practices stipulated in Annex 3 (titled “Meteorological Service for International Air Navigation”) to the Convention on International Civil Aviation (as in force and amended from time to time by the Council of the International Civil Aviation Organisation), and with such modifications as may be determined by the Authority to be applicable in Maldives. The standards and recommended practices contained in this Regulation, together with Regional Supplementary Procedures (Doc 7030), shall be applicable to all aspects of air navigation in the Maldives. Definitions of the terms and abbreviations used in this Regulation, unless the context requires otherwise, are in MCAR-1 Definitions and Abbreviations. Issue: 3.00 ii 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority List of Amendments List of Amendments Rev # Date Remarks Issue 1.00 2014-09-01 Initial Issue Issue 2.00 2021-08-11 Second Issue Incorporated ICAO Annex 3, Twentieth Edition Issue 3.00 2025-04-17 (Amendment 81) Issue: 3.00 iii 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority List of Effective Pages List of Effective Pages # Part Page Amendment Date Foreword ii Issue: 3.00 17 Apr 2025 List of Amendments iii Issue: 3.00 17 Apr 2025 List of Effective Pages iv-vi Issue: 3.00 17 Apr 2025 Table of Contents vii-xi Issue: 3.00 17 Apr 2025 Chapter 1 Definitions 1-1 Issue: 3.00 17 Apr 2025 Chapter 2 General Provisions 2-1 to 2-4 Issue: 3.00 17 Apr 2025 World Area Forecast System Chapter 3 3-1 to 3-3 Issue: 3.00 17 Apr 2025 and Meteorological Offices Meteorological Observations Chapter 4 4-1 to 4-6 Issue: 3.00 17 Apr 2025 and Reports Aircraft Observations and Chapter 5 5-1 to 5-3 Issue: 3.00 17 Apr 2025 Reports Chapter 6 Forecasts 6-1 to 6-3 Issue: 3.00 17 Apr 2025 IGMET and AIRMET Information, Aerodrome Chapter 7 7-1 to 7-2 Issue: 3.00 17 Apr 2025 Warnings and Wind Shear Warnings and Alerts Aeronautical Climatological Chapter 8 8-1 to 8-2 Issue: 3.00 17 Apr 2025 Information Service for Operators and Flight Chapter 9 9-1 to 9-5 Issue: 3.00 17 Apr 2025 Crew Members Information for Air Traffic Services, Search and Rescue Chapter 10 10-1 Issue: 3.00 17 Apr 2025 Services and Aeronautical Information Services Requirements for and Use of Chapter 11 11-1 to 11-3 Issue: 3.00 17 Apr 2025 Communications Evidences (Acronyms/ Records/ Chapter 12 12-1 to 12-3 Issue: 3.00 17 Apr 2025 References) Issue: 3.00 iv 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority List of Effective Pages # Part Page Amendment Date APP 1-1 Flight Documentation – Model Appendix 1 to Issue: 3.00 17 Apr 2025 Charts and Forms: APP 1-14 Technical Specifications Related APP 2-1 Appendix 2 to World Area Forecast System to Issue: 3.00 17 Apr 2025 and Meteorological Offices APP 2-8 Technical Specifications Related APP 3-1 Appendix 3 to Meteorological Observations to Issue: 3.00 17 Apr 2025 and Reports APP 3-35 Technical Specifications Related APP 4-1 Appendix 4 to Aircraft Observations and to Issue: 3.00 17 Apr 2025 Reports APP 4-7 APP 5-1 Technical Specifications Related Appendix 5 to Issue: 3.00 17 Apr 2025 to Forecasts APP 5-18 Technical Specifications Related to SIGMET and AIRMET APP 6-1 Appendix 6 Information, Aerodrome to Issue: 3.00 17 Apr 2025 Warnings and Wind Shear APP 6-24 Warnings and Alerts Technical Specifications Related APP 7-1 Appendix 7 to Aeronautical Climatological to Issue: 3.00 17 Apr 2025 Information APP 7-2 Technical Specifications Related APP 8-1 Appendix 8 to Service for Operators and to Issue: 3.00 17 Apr 2025 Flight Crew Members APP 8-10 Technical Specifications Related to Information for Air Traffic APP 9-1 Appendix 9 Services, Search and Rescue to Issue: 3.00 17 Apr 2025 Services and Aeronautical APP 9-5 Information Services Technical Specifications Related APP 10-1 Appendix 10 to Requirements for and Use of to Issue: 3.00 17 Apr 2025 Communications APP 10-5 Issue: 3.00 v 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority List of Effective Pages # Part Page Amendment Date Operationally Desirable Attachment A Accuracy of Measurement or ATT A-1 Issue: 3.00 17 Apr 2025 Observation ATT B-1 Operationally Desirable Attachment B to Issue: 3.00 17 Apr 2025 Accuracy of Forecasts ATT B-2 Selected Criteria Applicable to Attachment C ATT C-1 Issue: 3.00 17 Apr 2025 Aerodrome Reports Conversion of Instrumented ATT D-1 Attachment D Readings into Runway Visual to Issue: 3.00 17 Apr 2025 Range and Visibility ATT D-3 Issue: 3.00 vi 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Table of Contents Table of Contents Foreword ------------------------------------------------------------------------------------------------------------------ ii List of Amendments ----------------------------------------------------------------------------------------------------------------- iii List of Effective Pages ----------------------------------------------------------------------------------------------------------------- iv Table of Contents -----------------------------------------------------------------------------------------------------------------vii CHAPTER 1 DEFINITIONS 1-1 1.1 Definitions ----------------------------------------------------------------------------------------------- 1-1 1.2 Terms used with a limited meaning ------------------------------------------------------------ 1-1 CHAPTER 2 GENERAL PROVISIONS 2-1 2.1 Objective, determination and provision of meteorological service ------------------ 2-1 2.2 Supply, use, quality management and interpretation of meteorological information ---------------------------------------------------------------------------------------------- 2-1 2.3 Notifications required from operators --------------------------------------------------------- 2-3 CHAPTER 3 GLOBAL SYSTEMS, SUPPORTING CENTRES AND METEOROLOGICAL OFFICES 3-5 3.1 World area forecast system------------------------------------------------------------------------ 3-5 3.2 World area forecast centres ----------------------------------------------------------------------- 3-5 3.3 Aerodrome meteorological offices -------------------------------------------------------------- 3-5 3.4 Meteorological watch offices ---------------------------------------------------------------------- 3-6 3.5 Volcanic ash advisory centres (VAAC)----------------------------------------------------------- 3-7 3.6 State volcano observatories ----------------------------------------------------------------------- 3-7 3.7 Tropical cyclone advisory centres---------------------------------------------------------------- 3-7 3.8 Space weather centres ------------------------------------------------------------------------------ 3-7 CHAPTER 4 METEOROLOGICAL OBSERVATIONS AND REPORTS 4-2 4.1 Aeronautical meteorological stations and observations--------------------------------- 4-2 4.2 Agreement between the authorities providing air traffic services and meteorological services ----------------------------------------------------------------------------- 4-3 4.3 Routine observations and reports --------------------------------------------------------------- 4-3 4.4 Special observations and reports ---------------------------------------------------------------- 4-4 4.5 Contents of reports ----------------------------------------------------------------------------------- 4-4 4.6 Observing and reporting meteorological elements --------------------------------------- 4-5 4.7 Reporting meteorological information from automatic observing systems ------ 4-7 4.8 Observations and reports of volcanic activity ---------------------------------------------- 4-7 CHAPTER 5 AIRCRAFT OBSERVATIONS AND REPORTS 5-1 Issue: 3.00 vii 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Table of Contents 5.1 Obligations----------------------------------------------------------------------------------------------- 5-1 5.2 Types of aircraft observations -------------------------------------------------------------------- 5-1 5.3 Routine aircraft observations — designation ------------------------------------------------ 5-1 5.4 Routine aircraft observations — exemptions------------------------------------------------ 5-1 5.5 Special aircraft observations ---------------------------------------------------------------------- 5-1 5.6 Other non-routine aircraft observations ------------------------------------------------------ 5-2 5.7 Reporting of aircraft observations during flight -------------------------------------------- 5-2 5.8 Relay of air-reports by ATS units ----------------------------------------------------------------- 5-2 5.9 Recording and post-flight reporting of aircraft observations of volcanic activity 5-3 CHAPTER 6 FORECASTS 6-1 6.1 Use of forecasts ---------------------------------------------------------------------------------------- 6-1 6.2 Aerodrome forecasts--------------------------------------------------------------------------------- 6-1 6.3 Landing forecasts ------------------------------------------------------------------------------------- 6-2 6.4 Forecasts for take-off -------------------------------------------------------------------------------- 6-2 6.5 Area forecasts for low-level flights -------------------------------------------------------------- 6-2 CHAPTER 7 SIGMET AND AIRMET INFORMATION, AERODROME WARNINGS AND WIND SHEAR WARNINGS AND ALERTS 7-1 7.1 SIGMET information ---------------------------------------------------------------------------------- 7-1 7.2 AIRMET information ---------------------------------------------------------------------------------- 7-1 7.3 Aerodrome warnings--------------------------------------------------------------------------------- 7-2 7.4 Wind shear warnings and alerts------------------------------------------------------------------ 7-2 CHAPTER 8 AERONAUTICAL CLIMATOLOGICAL INFORMATION 8-1 8.1 General provisions ------------------------------------------------------------------------------------ 8-1 8.2 Aerodrome climatological tables----------------------------------------------------------------- 8-1 8.3 Aerodrome climatological summaries --------------------------------------------------------- 8-1 8.4 Copies of meteorological observational data------------------------------------------------ 8-2 CHAPTER 9 SERVICE FOR OPERATORS AND FLIGHT CREW MEMBERS 9-1 9.1 General provisions ------------------------------------------------------------------------------------ 9-1 9.2 Briefing, consultation and display --------------------------------------------------------------- 9-3 9.3 Flight documentation -------------------------------------------------------------------------------- 9-3 9.4 Automated pre-flight information systems for briefing, consultation, flight planning and flight documentation ----------------------------------------------------- 9-4 9.5 Information for aircraft in flight ------------------------------------------------------------------ 9-4 CHAPTER 10 INFORMATION FOR AIR TRAFFIC SERVICES, SEARCH AND RESCUE SERVICES AND AERONAUTICAL INFORMATION SERVICES 10-1 Issue: 3.00 viii 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Table of Contents 10.1 Information for air traffic services units ----------------------------------------------------- 10-1 10.2 Information for search and rescue services units---------------------------------------- 10-1 10.3 Information for aeronautical information service units ------------------------------- 10-1 CHAPTER 11 REQUIREMENTS FOR AND USE OF COMMUNICATIONS 11-1 11.1 Requirements for communication ------------------------------------------------------------ 11-1 11.2 Use of aeronautical fixed service communications and the public Internet- meteorological bulletins -------------------------------------------------------------------------- 11-2 11.3 Use of aeronautical fixed service communications — world area forecast system products ------------------------------------------------------------------------------------------------ 11-2 11.4 Use of aeronautical mobile service communications ----------------------------------- 11-2 11.5 Use of aeronautical data link service - contents of D-VOLMET ---------------------- 11-2 APPENDIX 1 FLIGHT DOCUMENTATION – MODEL CHARTS AND FORMS APP 1 APPENDIX 2 TECHNICAL SPECIFICATIONS RELATED TO GLOBAL SYSTEMS, SUPPORTING CENTRES AND METEOROLOGICAL OFFICES APP 2 1 World area forecast system------------------------------------------------------------------ APP 2-1 2 Aerodrome meteorological offices -------------------------------------------------------- APP 2-4 3 Volcanic Ash Advisory Centres -------------------------------------------------------------- APP 2-5 4 State Volcano Observatories ---------------------------------------------------------------- APP 2-5 5 Tropical cyclone advisory centres---------------------------------------------------------- APP 2-6 APPENDIX 3 TECHNICAL SPECIFICATIONS RELATED TO METEOROLOGICAL OBSERVATIONS AND REPORTS APP 3 1 General provisions related to meteorological observations --------------------- APP 3-1 2 General criteria related to meteorological reports ---------------------------------- APP 3-1 3 Dissemination of meteorological reports ----------------------------------------------- APP 3-4 4 Observing and reporting of meteorological elements------------------------------ APP 3-5 APPENDIX 4 TECHNICAL SPECIFICATIONS RELATED TO AIRCRAFT OBSERVATIONS AND REPORTS APP 4 1 Contents of air-reports ------------------------------------------------------------------------ APP 4-1 2 Criteria for reporting --------------------------------------------------------------------------- APP 4-3 3 Exchange of air-reports ----------------------------------------------------------------------- APP 4-5 4 Specific provisions related to reporting wind shear and volcanic ash -------- APP 4-5 APPENDIX 5 TECHNICAL SPECIFICATIONS RELATED TO FORECASTS APP 5 1 Criteria related to TAF-------------------------------------------------------------------------- APP 5-1 2 Criteria related to trend forecasts: -------------------------------------------------------- APP 5-6 Issue: 3.00 ix 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Table of Contents 3 Criteria related to forecasts for take-off ------------------------------------------------- APP 5-9 4 Criteria related to area forecasts for low level flights ------------------------------- APP 5-9 APPENDIX 6 TECHNICAL SPECIFICATIONS RELATED TO SIGMET AND AIRMET INFORMATION, AERODROME WARNINGS AND WIND SHEAR WARNINGS AND ALERTS APP 6 1 Specification related to SIGMET information ------------------------------------------ APP 6-1 2 Specifications related to AIRMET information ----------------------------------------- APP 6-3 3 Specifications related to special air-reports -------------------------------------------- APP 6-6 4 Detailed criteria related to SIGMET and AIRMET messages and special air- reports (UPLINK):--------------------------------------------------------------------------- APP 6-6 5 Specification related to aerodrome warnings ----------------------------------------- APP 6-8 6 Specifications related to wind shear warnings ---------------------------------------- APP 6-9 APPENDIX 7 TECHNICAL SPECIFICATIONS RELATED TO AERONAUTICAL CLIMATOLOGICAL INFORMATION APP 7 1 Processing of aeronautical climatological information ----------------------------- APP 7-1 2 Exchange of aeronautical climatological information ------------------------------ APP 7-1 3 Content of aeronautical climatological information --------------------------------- APP 7-1 APPENDIX 8 TECHNICAL SPECIFICATIONS RELATED TO SERVICE FOR OPERATORS AND FLIGHT CREW MEMBERS APP 8 1 Means of supply and format of meteorological information -------------------- APP 8-1 2 Specifications related to information for pre-flight planning and in-flight replanning------------------------------------------------------------------------------ APP 8-1 3 Specifications related to briefing and consultation ---------------------------------- APP 8-2 4 Specification related to flight documentation ----------------------------------------- APP 8-2 5 Specifications related to automated pre-flight information systems for briefing, consultation, flight planning and flight documentation ---------------------------- APP 8-6 6 Specifications related to information for aircraft in flight ------------------------- APP 8-6 APPENDIX 9 TECHNICAL SPECIFICATIONS RELATED TO INFORMATION FOR AIR TRAFFIC SERVICES, SEARCH AND RESCUE SERVICES AND AERONAUTICAL INFORMATION SERVICES APP 9 1 Information to be provided for air traffic services units --------------------------- APP 9-1 2 Information to be provided for search and rescue services units -------------- APP 9-3 3 Information to be provided for aeronautical information services units ---- APP 9-4 APPENDIX 10 TECHNICAL SPECIFICATIONS RELATED TO REQUIREMENTS FOR AND USE OF COMMUNICATIONS APP 10 1 Specific Requirements for Communications ----------------------------------------- APP 10-1 Issue: 3.00 x 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Table of Contents 2 Use of Aeronautical Fixed Service Communications and Public Internet ---------------------------------------------------------------------------------- APP 10-1 3 Use of Aeronautical Mobile Service Communications ---------------------------- APP 10-3 4 Use of Aeronautical Data Link Service — D-VOLMET------------------------------ APP 10-3 5 Use of Aeronautical Broadcasting Service — VOLMET broadcasts ----------- APP 10-4 APPENDIX 11 EVIDENCES (ACRONYMS/ RECORDS/ REFERENCES) APP 11 ATTACHMENT A OPERATIONALLY DESIRABLE ACCURACY OF MEASUREMENT OR OBSERVATION ATT A-1 ATTACHMENT B OPERATIONALLY DESIRABLE ACCURACY OF FORECASTS ATT B-1 ATTACHMENT C SELECTED CRITERIA APPLICABLE TO AERODROME REPORTS ATT C-1 ATTACHMENT D CONVERSION OF INSTRUMENTED READINGS INTO RUNWAY VISUAL RANGE AND VISIBILITY ATT D-1 Issue: 3.00 xi 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 1 — Definitions CHAPTER 1 DEFINITIONS Note. — The designation (RR) in these definitions indicates a definition which has been extracted from the Radio Regulations of the International Telecommunication Union (ITU) (see Handbook on Radio Frequency Spectrum Requirements for Civil Aviation including Statement of Approved ICAO Policies (Doc 9718)). 1.1 Definitions Definitions of the terms and abbreviations used in this Regulation, unless the context requires otherwise, are in MCAR-1 Definitions and Abbreviations. 1.2 Terms used with a limited meaning For the purpose of this MCAR, 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. Issue: 3.00 1-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 2 — General Specifications CHAPTER 2 GENERAL PROVISIONS 2.1 Objective, determination and provision of meteorological service 2.1.1 The objective of meteorological service for air navigation shall be to contribute towards the safety, regularity and efficiency of air navigation. 2.1.2 This 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 air navigation, with the meteorological information necessary for the performance of their respective functions. 2.1.3 This document prescribes the meteorological services to be provided by the designated meteorological authority to meet the needs of international air navigation. The meteorological services to be provided are determined in accordance with the provisions of Annex 3 and in accordance with Asia/Pacific regional air navigation agreements. It includes the meteorological services to be provided for international air navigation over international waters and other areas which lie outside the territory of the Maldives. 2.1.4 Maldives Meteorological Service (MMS) is the designated meteorological authority, to arrange for the provision of meteorological service for air navigation in such form and in such manner and at such places as maybe considered necessary to ensure the safe, economic and regular operation of aircraft and to give effect to the Convention. Details of the meteorological authority are included in the Aeronautical Information Publication of Maldives. 2.1.5 The meteorological authority shall comply with the requirements of the World Meteorological Organization (WMO) in respect of qualifications, competencies, education and training of meteorological personnel providing service for air navigation. Note. — Requirements concerning the qualifications, competencies, education and training of meteorological personnel in aeronautical meteorology are given in the Technical Regulations (WMO Publication No. 49), 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 air navigation. 2.2.2 The meteorological authority shall establish and implement a properly organized quality system comprising procedures, processes and resources necessary to provide for the Issue: 3.00 2-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 2 — General Specifications quality management of the meteorological information to be supplied to 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. — The International Organization for Standardization (ISO) 9000 series of quality assurance standards provide a basic framework for the development of a quality assurance programme. Guidance on the establishment and implementation of quality management systems 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 Chapter 3, 4, 6, 7, 8, 9 and 10 and Appendices 2, 3, 5, 6, 7, 8 and 9 of this Regulation and the relevant regional air navigation plans. Guidance concerning the accuracy of measurement and observation, and accuracy of forecasts is given in Attachments A and B, respectively. 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 Chapter 11 and Appendix 10 of this Regulation. 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 evidenced 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. Issue: 3.00 2-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 2 — General Specifications 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. 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 chapters. Note. — Guidance material on the application of Human Factors principles can be found in the Human Factors Training Manual (Doc 9683). 2.2.10 The meteorological authority 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-to-machine interaction in a service-oriented architecture. Note 2.— Procedures on information services are contained in the Procedures for Air Navigation Services - Information Management (PANS-IM, Doc 10199). Note 3.— Guidance material on information services can be found in the Manual on System- wide Information Management 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, sufficiently in advance, the meteorological authority or the meteorological office(s) concerned. The minimum amount of advance notice required shall be as agreed between the meteorological authority or meteorological office(s) and the operator concerned. 2.3.2 The meteorological authority 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 the meteorological authority. 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; Issue: 3.00 2-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 2 — General Specifications 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(s) at which briefing, consultation and/or flight documentation are required. Issue: 3.00 2-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 3 — World Area Forecast System and Meteorological Offices CHAPTER 3 GLOBAL SYSTEMS, SUPPORTING CENTRES AND METEOROLOGICAL OFFICES Note. — Technical specifications and detailed criteria related to this chapter are given in Appendix 2. 3.1 World area forecast system 3.1.1 The objective of the world area forecast system (WAFS) shall be to supply meteorological authorities and other users with global aeronautical meteorological en-route forecasts in digital form. This objective shall be achieved through a comprehensive, integrated, worldwide and, as far as practicable, uniform system, and in a cost-effective manner, taking full advantage of evolving technologies. 3.2 World area forecast centres 3.2.1 The requirements for WAFC are stipulated in Chapter 3 of ICAO Annex 3, for the meteorological authority who have accepted the responsibilities for providing a WAFC, the products and services required within the framework of the world area forecast system. 3.2.2 In case of interruption of the operation of a WAFC, its functions shall be carried out by the other WAFC. 3.3 Aerodrome meteorological offices 3.3.1 The meteorological authority 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 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. Issue: 3.00 3-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 3 — World Area Forecast System and Meteorological Offices h) supply information received on pre-eruption volcanic activity, a volcanic eruption or volcanic ash cloud, to its associated air traffic services unit, 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 aerodrome meteorological office located at the aerodrome: a) The meteorological authority shall designate one or more meteorological offices to supply meteorological information as required; and b) the meteorological authority shall establish means by which such information can be supplied to the aerodromes concerned. 3.4 Meteorological watch offices 3.4.1 MMS (Maldives Meteorological Services) is the main MWO and is located at Velana International Airport. There are 4 sub watch offices working under MMS providing routine aviation met reports to different areas of the Maldives. 3.4.2 A meteorological watch office (MWO) shall: a) maintain continuous 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 area control centre (ACC)/flight information centre (FIC), as agreed between the meteorological and ATS authorities concerned, and to its associated VAAC as determined by regional air navigation agreement; and g) supply information received concerning the release of radioactive materials into the atmosphere in Male’ FIR or adjacent areas, to the ACC and AIS units. The information shall comprise location, date and time of the release, and forecast trajectories of the radioactive materials. 3.4.3 The boundaries of the area over which meteorological watch is to be maintained by MMS should be coincident with the boundaries of Maldives FIR. Issue: 3.00 3-6 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 3 — World Area Forecast System and Meteorological Offices 3.4.4 The MWO should coordinate SIGMET with neighboring MWO(s), especially when the enroute weather phenomenon extends or is expected to extend beyond the MWO’s specified area of responsibility, in order to ensure the provision of harmonized SIGMET. 3.5 Volcanic ash advisory centres (VAAC) 3.5.1 ICAO stipulates in Chapter 3 of Annex 3 the products and services required of the meteorological authority which have accepted responsibilities for providing a VAAC within the framework of the world area forecast system. Maldives is not a VAAC. 3.6 State volcano observatories 3.6.1 ICAO stipulates in Chapter 3 of Annex 3 the requirements for contracting states which maintain volcano observatories monitoring active volcanoes. 3.6.2 Maldives does not maintain any volcano observatories. 3.7 Tropical cyclone advisory centres 3.7.1 ICAO stipulates in Chapter 3 of Annex 3 the products and services required of the contracting states which have accepted responsibilities for providing a TCAC within the framework of the world area forecast system. 3.7.2 Maldives is not a TCAC. 3.8 Space weather centres 3.8.1 ICAO stipulates in Chapter 3 of Annex 3 the requirements for contracting states which have accepted responsibilities for providing a SWXC for that centre to monitor and provide advisory information on space weather phenomena in its area of responsibility. 3.8.2 Maldives does not maintain any space weather centres. Issue: 3.00 3-7 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 4 — Meteorological Observations and Reports CHAPTER 4 METEOROLOGICAL OBSERVATIONS AND REPORTS Note. — Technical specifications and detailed criteria related to this chapter are prescribed in Appendix 3. 4.1 Aeronautical meteorological stations and observations 4.1.1 The meteorological authority shall establish, at aerodromes in the Maldives, 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 air navigation with the provisions of this Regulation. 4.1.2 The meteorological authority should establish, or arrange for the establishment of, aeronautical meteorological stations on offshore structures or at other points of significance in support of helicopter operations to offshore structures. 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 The meteorological authority shall arrange for its aeronautical meteorological stations to be inspected at sufficiently frequent intervals to ensure that a high standard of observation is maintained, that instruments and all their indicators are functioning correctly, and that the exposure of the instruments has not 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 MCAR OPS- 1. Note. 2 — Guidance material on the application of Human Factors principles can be found in the Human Factors Training Manual (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 Issue: 3.00 4-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 4 — Meteorological Observations and Reports 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. 4.2 Agreement between the authorities providing air traffic services and meteorological services 4.2.1 An agreement between the meteorological authority and the appropriate ATS authority shall be established to cover, among 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 Manual on Coordination between Air Traffic Services, Aeronautical Information Services and Aeronautical Meteorological Services (Doc 9377). 4.3 Routine observations and reports 4.3.1 At aerodromes, routine observations shall be made throughout the 24 hours each day, except as otherwise agreed between the meteorological authority, the ATS provider and the operator concerned. Such observations shall be made at intervals of one hour. At other aeronautical meteorological stations, such observations shall be made as Issue: 3.00 4-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 4 — Meteorological Observations and Reports determined by the meteorological authority 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 MCAR11, 4.3.6.1 g). 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 regional air navigation agreement. 4.4 Special observations and reports 4.4.1 List of criteria for special observations shall be established by the meteorological authority, in consultation with the ANS provider, 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 MCAR 11, 4.3.6.1 g). 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; Issue: 3.00 4-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 4 — Meteorological Observations and Reports 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 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 meters 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 MCAR 1 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 4.6.2.2 When local routine and special reports are used for departing aircraft, the visibility observations for these reports should be representative of conditions along the runway; when local routine and special reports are used for arriving aircraft, the visibility observations for these reports should be representative of the touchdown zone of the runway. 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 Manual of Runway Visual Range Observing and Reporting Practices (Doc 9328). Issue: 3.00 4-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 4 — Meteorological Observations and Reports 4.6.3.1 Runway visual range as defined in MCAR 1 shall be assessed on all runways intended for Category II and III instrument approach and landing operations. 4.6.3.2 Runway visual range as defined in MCAR 1 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/or centre line lights Note. — Precision approach runways are defined in MCAR 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 metres throughout periods when either the visibility or the runway visual range is less than 1 500m. 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 intended for 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 and (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 should be representative of conditions at the aerodrome. 4.6.4.3 For METAR and SPECI, the present weather information should 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 base. The height of cloud base and vertical visibility shall be reported in metres (or feet). 4.6.5.2 Cloud observations for local routine and special reports should be representative of the runway threshold(s) in use. Issue: 3.00 4-6 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 4 — Meteorological Observations and Reports 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 4.6.7.1 The atmospheric pressure shall be measured, and QNH and QFE values shall be computed and reported in hectopascals. 4.6.8 Supplementary information 4.6.8.1 Observations made at aerodromes should 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 4.7.1 METAR and SPECI from automatic observing systems should be used by the concerned authorities in a position to do so during non-operational hours of the aerodrome, and during operational hours of the aerodrome as determined by the meteorological authority in consultation with users based on the availability and efficient use of personnel. Note. — Guidance on the use of automatic meteorological observing systems is given Doc 9837. 4.7.2 Local routine reports and local special reports from automatic observing systems shall be used if in a position to do so during operational hours of the aerodrome as determined by the meteorological authority in consultation with users based on the availability and efficient use of personnel. 4.7.3 Local routine reports, local special reports, METAR and SPECI from automatic observing systems shall be identified with the word “AUTO”. 4.8 Observations and reports of volcanic activity 4.8.1 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; Issue: 3.00 4-7 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 4 — Meteorological Observations and Reports 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. Note. — Pre-eruption volcanic activity in this context means unusual and/or increasing volcanic activity which could presage a volcanic eruption. Issue: 3.00 4-8 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 5 — Aircraft Observations and Reports CHAPTER 5 AIRCRAFT OBSERVATIONS AND REPORTS Note. — Technical specifications and detailed criteria related to this chapter are given in Appendix 4. 5.1 Obligations 5.1.1 The meteorological authority shall be familiar with the arrangement for aircraft routine and special observations so as to be able to use and disseminate these observations effectively. 5.2 Types of aircraft observations 5.2.1 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 5.4.1 Aircraft not equipped with air-ground data link shall be exempted from making routine aircraft observations. 5.5 Special aircraft observations 5.5.1 Special observations shall be made by all aircraft whenever the following conditions are encountered or observed: a) moderate or severe turbulence; or Issue: 3.00 5-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 5 — Aircraft Observations and Reports 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 duststorm or heavy sandstorm; or g) volcanic ash cloud; or h) pre-eruption volcanic activity or a volcanic eruption; or Note. — Pre-eruption volcanic activity in this context means unusual and/or increasing volcanic activity which could presage a volcanic eruption. i) runway braking action encountered is not as good as reported. 5.6 Other non-routine aircraft observations 5.6.1 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 ATS units 5.8.1 The meteorological authority shall make arrangements with the ATS provider 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 meteorological watch office; and b) routine and special air-reports by data link communications, the ATS units relay them without delay to their associated meteorological watch office, the WAFCs and the centres designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services. Issue: 3.00 5-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 5 — Aircraft Observations and Reports 5.9 Recording and post-flight reporting of aircraft observations of volcanic activity 5.9.1 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. Issue: 3.00 5-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 6 — Forecasts CHAPTER 6 FORECASTS Note. — Technical specifications and detailed criteria related to this chapter are given in Appendix 5. 6.1 Use of forecasts 6.1.1 The issue of a new forecast by an aerodrome meteorological office, such as a routine aerodrome forecast, shall be understood to cancel automatically any 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. 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 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. Note. — The visibility included in TAF refers to the forecast prevailing visibility. Issue: 3.00 6-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 6 — Forecasts 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 (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 6 hours and not 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 as determined by regional air navigation agreement; such forecasts are intended to meet the 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, 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 Maldives Meteorological Services. 6.4.2 A forecast for take-off should 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. 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 Meteorological office 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 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 Issue: 3.00 6-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 6 — Forecasts amendments thereto shall be determined by the meteorological authority in consultation with the users. 6.5.2 When the density of traffic operating below flight level 100 warrants the issuance of AIRMET information in accordance with 7.2.1, area forecasts for such operations shall be prepared in a format as agreed between the meteorological authorities concerned. When abbreviated plain language is used, the forecast shall be prepared as a GAMET area forecast, employing approved ICAO abbreviations and numerical values; when chart form is used, the forecast shall be prepared as a combination of forecasts of upper wind and upper-air temperature, and of SIGWX phenomena. The area forecasts shall be issued to cover the layer between the ground and flight level 100 (or up to flight level 150 in mountainous areas, or higher, where necessary) and shall contain information on en-route weather phenomena hazardous to low-level flights, in support of the issuance of AIRMET information, and additional information required by low-level flights. 6.5.3 Area forecasts for low-level flights prepared in support of the issuance of AIRMET information shall be issued every 6 hours for a period of validity of 6 hours and transmitted to meteorological watch offices and/or aerodrome meteorological offices concerned not later than one hour prior to the beginning of their validity period. Issue: 3.00 6-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 7 - SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts CHAPTER 7 SIGMET AND AIRMET INFORMATION, AERODROME WARNINGS AND WIND SHEAR WARNINGS AND ALERTS Note. — Technical specifications and detailed criteria related to this chapter are given in Appendix 6. 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 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 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 messages for tropical cyclones, these messages shall be issued not more than 12 hours before the commencement of the period of validity. SIGMET messages for tropical cyclones shall be updated at least every 6 hours. 7.2 AIRMET information 7.2.1 AIRMET information shall be issued by a meteorological watch office in accordance with regional air navigation agreement, taking into account the density of air traffic operating below flight level 100. AIRMET information shall give a concise description in abbreviated plain language concerning the occurrence and/or expected occurrence of specified en- route weather phenomena, which have not been included in Section I of the area forecast for low-level flights issued in accordance with Chapter 6, Section 6.5 and which may affect the safety of low-level flights, and of the development of those phenomena in time and space. 7.2.2 AIRMET information shall be cancelled when the phenomena are no longer occurring or are no longer expected to occur in the area. Issue: 3.00 7-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 7 - SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts 7.2.3 The period of validity of an AIRMET message shall be not more than 4 hours. 7.3 Aerodrome warnings 7.3.1 Aerodrome warnings shall be issued by the aerodrome meteorological office 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 should 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 aerodrome meteorological office designated by the meteorological authority concerned for aerodromes where wind shear is considered a factor, in accordance with local arrangements with the appropriate ATS unit and operators concerned. Wind shear warnings shall give concise information on the observed or expected existence of wind shear which could adversely affect aircraft on the approach path or take-off path or during circling approach between runway level and 500 m (1 600 ft) above that level and aircraft on the runway during the landing roll or take-off run. Where local topography has been shown to produce significant wind shears at heights in excess of 500 m (1 600 ft) above runway level, then 500 m (1 600 ft) shall not be considered restrictive. 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 an agreed elapsed time. The criteria for the cancellation of a wind shear warning should be defined locally for each aerodrome, as agreed between the meteorological authority, ATS provider 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-off path and aircraft on the runway during the landing roll or take-off run. 7.4.4 Wind shear alerts 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). Issue: 3.00 7-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 8 — Aeronautical Climatological Information CHAPTER 8 AERONAUTICAL CLIMATOLOGICAL INFORMATION Note. — Technical specifications and detailed criteria related to this chapter are given in Appendix 7. 8.1 General provisions Note. — In cases where it is impracticable to meet the requirements for aeronautical climatological information on a national basis, the collection, processing and storage of observational data may be effected through computer facilities available for international use, and the responsibility for the preparation of the required aeronautical climatological information may be delegated by agreement between the meteorological authorities concerned. 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 those users. Note. — Climatological data required for aerodrome planning purposes are set out in ASC 139-5, 3.1.4 and Attachment A of this MCAR. 8.1.2 Aeronautical climatological information should 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 8.2.1 The meteorological authority 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 Maldives; and b) to make available such climatological tables to an aeronautical user within a time period as agreed between the meteorological authority and the user concerned. 8.3 Aerodrome climatological summaries 8.3.1 Aerodrome climatological summaries shall 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 WMO and should be published and kept up to date as necessary. Issue: 3.00 8-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 8 — Aeronautical Climatological Information 8.4 Copies of meteorological observational data 8.4.1 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 air navigation, meteorological observational data required for research, investigation or operational analysis. Issue: 3.00 8-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 9 — Service for Operators and Flight Crew Members CHAPTER 9 SERVICE FOR OPERATORS AND FLIGHT CREW MEMBERS Note. — Technical specifications and detailed criteria related to this chapter are given in Appendix 8 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 replanning 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 alternate aerodromes 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, as established by the meteorological authority in consultation with operators concerned: 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; and 6. SIGWX phenomena; 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 clouds, icing and turbulence are intended to be processed and, if necessary, visualized according to the specific thresholds relevant to user operations. 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; Issue: 3.00 9-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 9 — Service for Operators and Flight Crew Members 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 forecasts and/or area forecasts for low-level flights in chart form prepared in 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 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 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, the meteorological authority shall initiate coordinating action with the meteorological 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. The service for pre-flight planning shall be confined to flights originating within Maldives. At Issue: 3.00 9-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 9 — Service for Operators and Flight Crew Members an aerodrome without an aerodrome meteorological office, arrangements for the supply of meteorological information shall be as agreed upon between the meteorological authority and the operator concerned. 9.2 Briefing, consultation and display Note. — The requirements for the use of automated pre-flight information systems in providing briefing, consultation and display are given in 9.4. 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, if so agreed between the meteorological authority and the operator, in lieu of flight documentation. 9.2.2 Meteorological information used for briefing, consultation and display 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 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 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 Note. — The requirements for the use of automated pre-flight information systems in providing flight documentation are given in 9.4. 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, when agreed between the Issue: 3.00 9-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 9 — Service for Operators and Flight Crew Members meteorological authority and operator concerned, flight documentation for flights of two hours’ duration or less, after a short stop or turn around, shall be limited to the information operationally needed, 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 replanning, the operator shall be advised immediately if practicable, and 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 air traffic services unit, for transmission to the aircraft. 9.3.4 The meteorological authority 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 the meteorological authority 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 The meteorological authority shall establish an agreement with the ATS provider to establish automated pre-flight information systems providing for a harmonised, common point of access to meteorological information and aeronautical information services information by operators, flight crew members and other aeronautical personnel concerned. 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, the meteorological authority shall remain responsible for the quality control and quality management of meteorological information provided by means of such systems in accordance with Chapter 2, 2.2.2. 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 meteorological watch office to its associated air traffic services unit and through D-VOLMET or VOLMET broadcasts as determined by regional air navigation agreement. Meteorological information for planning by the Issue: 3.00 9-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 9 — Service for Operators and Flight Crew Members operator for aircraft in flight shall be supplied on request, as agreed between the meteorological authority or authorities and the operator concerned. 9.5.2 Meteorological information for use by aircraft in flight shall be supplied to air traffic services units in accordance with the specifications of Chapter 10. 9.5.3 Meteorological information shall be supplied through D-VOLMET or VOLMET broadcasts in accordance with the specifications of Chapter 11. Issue: 3.00 9-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 10 — Information for Air Traffic Services, Search and Rescue Services and Aeronautical Information Services CHAPTER 10 INFORMATION FOR AIR TRAFFIC SERVICES, SEARCH AND RESCUE SERVICES AND AERONAUTICAL INFORMATION SERVICES Note. — Technical specifications and detailed criteria related to this chapter are given in Appendix 9. 10.1 Information for air traffic services units 10.1.1 The meteorological authority shall designate an aerodrome meteorological office or meteorological watch office to be associated with each air traffic services unit. The associated aerodrome meteorological office or meteorological watch office shall, after coordination with the air traffic services 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 meteorological watch office shall be associated with a flight information centre or an area control centre for the provision of meteorological information. 10.1.4 Where, owing to local circumstances, it is convenient for the duties of an associated aerodrome meteorological office or meteorological watch office to be shared between two or more aerodrome meteorological offices, 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 air traffic services unit in connection with an aircraft emergency shall be supplied as rapidly as possible. 10.2 Information for search and rescue services units 10.2.1 Aerodrome Meteorological offices or meteorological watch offices 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 shall maintain liaison with the search and rescue services unit throughout a search and rescue operation. 10.3 Information for aeronautical information service units 10.3.1 The Aerodrome Meteorological office 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. Issue: 3.00 10-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 11 – Requirements for and use of Communications CHAPTER 11 REQUIREMENTS FOR AND USE OF COMMUNICATIONS Note 1. — Technical specifications and detailed criteria related to this chapter are given in Appendix 10 11.1 Requirements for communication 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 air traffic services 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 meteorological watch offices to supply the required meteorological information to air traffic services and search and rescue services units in respect of the flight information regions, control areas and search and rescue regions for which those offices are responsible, and in particular to flight information centres, area control centres and rescue coordination centres and the associated aeronautical telecommunications stations. 11.1.3 Suitable telecommunications facilities shall be made available to permit world area forecast centres to supply the required world area forecast system 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 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. 11.1.5 Telecommunications facilities between aerodrome meteorological offices or meteorological watch offices and flight information centres, area control centres, 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 11.1.4 and 11.1.5 should be supplemented, as and where necessary, by other forms of visual or audio communications, for example, closed-circuit television or separate information processing systems. Issue: 3.00 11-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 11 – Requirements for and use of Communications 11.1.7 The meteorological authority shall make provision for all users to obtain 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 world area forecast centres, 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 information and relevant aspects of the public Internet is provided in the ICAO Guidelines on the Use of the Public Internet for Aeronautical Applications (Doc 9855). 11.2 Use of aeronautical fixed service communications and the public Internet- meteorological bulletins 11.2.1 Meteorological bulletins containing operational meteorological information to be transmitted via the aeronautical fixed service or the 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 ICAO Annex 10, Volume II, Chapter 4, together with the relevant priorities and priority indicators. 11.3 Use of aeronautical fixed service communications — world area forecast system products 11.3.1 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 11.4.1 The content and format of meteorological information transmitted to aircraft and by aircraft shall be consistent with the provisions of this Regulation. 11.5 Use of aeronautical data link service - contents of D-VOLMET 11.5.1 D-VOLMET shall contain current METAR and SPECI, together with trend forecasts where available, TAF and SIGMET, special air-reports not covered by a SIGMET and, where available, AIRMET. Issue: 3.00 11-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Chapter 11 – Requirements for and use of Communications Note. — The requirement to provide METAR and SPECI may be met by the data link-flight information service (D-FIS) application entitled “Data link-aerodrome routine meteorological report (D-METAR) service”; the requirement to provide TAF may be met by the D-FIS application entitled “Data link-aerodrome forecast (D-TAF) service”; and the requirement to provide SIGMET and AIRMET messages may be met by the D-FIS application entitled “Data link-SIGMET (D-SIGMET) service”. The details of these data link services are specified in the ICAO Manual of Air Traffic Services Data Link Applications (Doc 9694). 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. Issue: 3.00 11-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms APPENDIX 1 FLIGHT DOCUMENTATION – MODEL CHARTS AND FORMS (See Chapter 9 of this MCAR.) MODEL A OPMET information Upper wind and upper-air temperature chart for standard isobaric surface MODEL IS Example 1: Arrows, feathers and pennants (Mercator projection) Example 2: Arrows, feathers and pennants (Polar stereographic projection) Significant weather chart (high level) MODEL SWH Example: Polar stereographic projection (showing the jet stream vertical extent) MODEL SWM Significant weather chart (medium level) Significant weather chart (low level) MODEL SWL Example 1 Example 2 MODEL TCG Tropical cyclone advisory information in graphical format Volcanic ash advisory information in graphical format MODEL VAG Example 1. Mercator projection Example 2. Polar stereographic projection MODEL STC SIGMET for tropical cyclone in graphical format MODEL SVA (Not Applicable) SIGMET for phenomena other than tropical cyclone in graphical MODEL SGE format MODEL SN Sheet of notations used in flight documentation Issue: 3.00 APP 1-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 1. OPMET Information – Model A Issue: 3.00 APP 1-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 2. Upper wind and temperature chart for standard isobaric surface – Model IS Example 1 – Arrows, feathers and pennants (Mercator projection) Issue: 3.00 APP 1-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms Example 2 – Arrows, feathers and pennants (Polar stereographic projection) Issue: 3.00 APP 1-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 3. Significant weather chart (high level) – Model SWH Example – Polar stereographic projection (showing the jet stream vertical extend) Issue: 3.00 APP 1-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 4. Significant weather chart (medium level) − Model SWM Issue: 3.00 APP 1-6 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 5. Significant weather chart (low level) − Model SWL Example 1 Issue: 3.00 APP 1-7 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 6. Significant weather chart (low level) − Model SWL Example 2 Issue: 3.00 APP 1-8 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 7. Tropical cyclone advisory information in graphical format − Model TCG Issue: 3.00 APP 1-9 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 8. Volcanic Ash Advisory Information in Graphical Format – Model VAG Example 1. Mercaptor projection Issue: 3.00 APP 1-10 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 9. Volcanic Ash Advisory Information in Graphical Format – Model VAG Example 2. Polar stereographic projection Issue: 3.00 APP 1-11 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 10. SIGMET for tropical cyclone in graphical format − Model STC Issue: 3.00 APP 1-12 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 11. SIGMET for Volcanic Ash in Geographical Format – Model SVA Example 1. Mercaptor projection Issue: 3.00 APP 1-13 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 12. SIGMET for Volcanic Ash in Geographical Format – Model SVA Example 1. Polar stereographic projection Issue: 3.00 APP 1-14 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 13. SIGMET for phenomena other than tropical cyclone − Model SGE Issue: 3.00 APP 1-15 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 1 — Flight Documentation – Model Charts and Forms 14. Sheet of notations used in flight documentation − Model SN Issue: 3.00 APP 1-16 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices APPENDIX 2 TECHNICAL SPECIFICATIONS RELATED TO GLOBAL SYSTEMS, SUPPORTING CENTRES AND METEOROLOGICAL OFFICES (See Chapter 3 of this MCAR.) 1 World area forecast system 1.1 Formats and codes World area forecast centres (WAFCs) shall adopt uniform formats and codes for the supply of forecasts. 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 shall be disseminated as soon as technically feasible but not later than 5 hours after standard time of observation. 1.2.2 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) and 180 (500 hPa); e) horizontal extent and flight levels of base and top of cumulonimbus clouds; f) icing for layers centred at flight levels 60 (800 hPa), 100 (700 hPa), 140 (600 hPa), 180 (500 hPa), 240 (400 hPa) and 300 (300 hPa); Note. — Layers centred at a flight level referred to in f) have a depth of 100 hPa. g) turbulence for layers centred 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) 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. Issue: 3.00 APP 2-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices 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), d), 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 the GRIB 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, Part B — Binary Codes. 1.2.4 The foregoing grid point forecasts a), b), c), d) and h) shall be prepared by a WAFC in a regular 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. 1.3 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 prescribed by 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 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). 1.3.2 Types of SIGWX forecasts SIGWX forecasts shall be issued as high-level SIGWX forecasts for flight levels between 250 and 630. Note. — Medium-level SIGWX forecasts for flight levels between 100 and 250 for limited geographical areas will continue to be issued until such time that flight documentation to be generated from the gridded forecasts of cumulonimbus clouds, icing and turbulence fully meets user requirements. 1.3.3 Items included in SIGWX forecasts Issue: 3.00 APP 2-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices SIGWX forecasts shall include the following items: a) tropical cyclone provided that the maximum of the 10-minute mean surface wind speed is expected to reach or exceed 17 m/s (34 kt); b) severe squall lines; c) moderate or severe turbulence (in cloud or clear-air); d) moderate or severe icing; e) widespread sandstorm/duststorm; f) cumulonimbus clouds associated with thunderstorms and with a) to e); Note. — Non-convective cloud areas associated with in-cloud moderate or severe turbulence and/or moderate or severe icing are to be included in the SIGWX forecasts. g) flight level of tropopause; h) jet streams; i) information on the location of volcanic eruptions that are producing ash clouds of significance to aircraft operations, comprising: volcanic eruption symbol at the location of the volcano and, in a separate text box on the chart, the volcanic eruption symbol, the name of the volcano (if known) and the latitude/longitude of the eruption. In addition, the legend of SIGWX charts should indicate “CHECK SIGMET, ADVISORIES FOR TC AND VA, AND ASHTAM AND NOTAM FOR VA”; and j) information on the location of a release of radioactive materials into the atmosphere of significance to aircraft operations, comprising: the radioactive materials in the atmosphere symbol at the location of the release and, in a separate text box on the chart, the radioactive materials in the atmosphere symbol, latitude/longitude of the site of the release, and (if known) the name of site of the radioactive source. In addition, the legend of SIGWX charts on which a release of radiation is indicated should contain “CHECK SIGMET AND NOTAM FOR RDOACT CLD”. Note 1. — Medium-level SIGWX forecasts include all the items above. Note 2.— Items to be included in low-level SIGWX forecasts (i.e. flight levels below 100) are included in Appendix 5. 1.3.4 Criteria for including items in SIGWX forecasts The following criteria shall be applied for SIGWX forecasts: a) items a) to f) in 1.3.3 shall only be included if expected to occur between the lower and upper levels of the SIGWX forecast; b) the abbreviation “CB” shall only be included when it refers to the occurrence or expected occurrence of cumulonimbus clouds: 1. affecting an area with a maximum spatial coverage of 50 per cent or more of the area concerned; 2. along a line with little or no space between individual clouds; or Issue: 3.00 APP 2-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices 3. embedded in cloud layers or concealed by haze; c) the inclusion of “CB” shall be understood to include all weather phenomena normally associated with cumulonimbus clouds, i.e. thunderstorm, moderate or severe icing, moderate or severe turbulence and hail; d) where a release of radioactive materials into the atmosphere warrants the inclusion of radioactive materials in the atmosphere symbol in SIGWX forecasts, the symbols shall be included on SIGWX forecasts irrespective of the height to which the ash column or radioactive material is reported or expected to reach; and e) in the case of co-incident or the partial overlapping of items a), i) and j) in 1.3.3, the highest priority shall be given to item i), followed by items j) and a). The item with the highest priority shall be placed at the location of the event, and an arrow shall be used to link the location of the other item(s) to its associated symbol or text box. 2 Aerodrome meteorological offices 2.1 Use of world area forecast system (WAFS) products 2.1.1 Aerodrome meteorological offices shall use WAFS forecasts issued by the 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. 2.1.2 In order to ensure uniformity and standardization of flight documentation, the WAFS GRIB, BUFR and IWXXM data received, shall be decoded into standard WAFS charts in accordance with relevant provisions in this MCAR, 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 IWXXM data shall notify the WAFC concerned immediately if significant discrepancies are detected or reported 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/duststorms; and b) volcanic eruptions or a release of radioactive materials into the atmosphere, of significance to aircraft operations. The WAFC receiving the message shall acknowledge its receipt to the originator, together with a 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). Issue: 3.00 APP 2-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices 3 Volcanic Ash Advisory Centres 3.1 Volcanic Ash Advisory information 3.1.1 The advisory information on volcanic ash issued in abbreviated plain language, using approved ICAO abbreviations and numerical values of self-explanatory nature, shall be in accordance with the template shown in Table A2-1. When no approved ICAO abbreviations are available, English plain language text, to be kept to a minimum, shall be used. 3.1.2 Volcanic ash advisory information shall be disseminated in IWXXM GML form in addition to the dissemination of this advisory information in accordance with 3.1.1. Note 1. — 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). Note 2. — Geography markup language (GML) is an encoding standard of the Open Geospatial Consortium (OGC). 3.1.3 The volcanic ash advisory information listed in Table A2-1, when prepared in graphical format, shall be as specified in Appendix 1 and issued using the portable network graphics (PNG) format. 4 State Volcano Observatories 4.1 Information from State volcano observatories The information required to be sent by State volcano observatories to their associated area control centres (ACCs)/flight information centres (FICs), meteorological watch office (MWO) and VAAC should comprise: 1) for significant pre-eruption volcanic activity: the date/time (UTC) of report; name and, if known, number of the volcano; location (latitude/longitude); and description of volcanic activity; and 2) for volcanic eruption: the date/time (UTC) of report and time of eruption (UTC) if different from time of report; name and, if known, number of the volcano; location (latitude/longitude); and description of the eruption including whether an ash column was ejected and, if so, an estimate of height of ash column and the extent of any visible volcanic ash cloud, during and following an eruption; and 3) for volcanic eruption cessation: the date/time (UTC) of report and time of eruption cessation (UTC); name and, if known, number of the volcano; and location (latitude/longitude). Note 1.— Pre-eruption volcanic activity in this context means unusual and/or increasing volcanic activity which could presage a volcanic eruption Note 2.— The State volcano observatories may use the Volcano Observatory Notice for Aviation (VONA) format to send information to their associated ACCs/FICs, MWO and VAAC. The VONA format is included in the Handbook on the International Airways Volcano Watch Issue: 3.00 APP 2-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices (IAVW) — Operational Procedures and Contact List (Doc 9766) which is available on the ICAO website 5 Tropical cyclone advisory centres 5.1 Tropical cyclone advisory information 5.1.1 The advisory information on tropical cyclones shall be issued for tropical cyclones 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-explanatory nature, shall be in accordance with the template shown in Table A2-2. 5.1.3 Tropical cyclone advisory centres shall disseminate tropical cyclone advisory information in IWXXM GML form in addition to the dissemination of this advisory information in abbreviated plain language in accordance with 5.1.2. Note 1. — 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). Note 2. — Geography markup language (GML) is an encoding standard of the Open Geospatial Consortium (OGC). 5.1.4 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. 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 subsequent line. Note 1. — The ranges and resolutions for the numerical elements included in advisory messages for volcanic ash are shown in Appendix 6, Table A6-4. 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). 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 examples. Issue: 3.00 APP 2-6 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices Issue: 3.00 APP 2-7 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices Issue: 3.00 APP 2-8 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices Notes. — 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". 2. International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI). 3. A straight line between two points drawn on a map in the Mercator Projection or a straight line between two points which crosses lines of longitude at a constant angle. 4. Up to 4 selected layers. 5. If ash reported (e.g. AIREP) but not identifiable from satellite data 6. To be included (as free text) only for those situation where volcanic ash has been re-suspended. 7. To be included (as free text) where space in the remarks section allows Example A2-1. Advisory message for volcanic ash Issue: 3.00 APP 2-9 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices Table A2-2. Template for advisory message for tropical cyclones Key: = M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable; O = inclusion optional; = = 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 advisory messages for tropical cyclones are shown in Appendix 6, Table A6-4. Note 2. — The explanations for the abbreviations can be found in the PANS-ABC (Doc 8400). Note 3. — Inclusion of a colon after each element heading is mandatory. Note 4. — The numbers 1 to 21 are included only for clarity and are not part of the advisory message, as shown in the examples. Issue: 3.00 APP 2-10 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices Issue: 3.00 APP 2-11 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices Notes. — 8. 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". 9. Fictitious location. 10. In the case of CB clouds associated with a tropical cyclone covering more than one area within the area of responsibility, this element can be repeated, as necessary. 11. The number of coordinates should be kept to a minimum and should not normally exceed seven. Issue: 3.00 APP 2-12 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 2 —Technical Specifications Related to World Area Forecast System and Meteorological Offices Example A2-2. Advisory message for tropical cyclones Issue: 3.00 APP 2-13 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports APPENDIX 3 TECHNICAL SPECIFICATIONS RELATED TO METEOROLOGICAL OBSERVATIONS AND REPORTS (See Chapter 4 of this MCAR.) 1 General provisions related to meteorological observations 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 ASC 139-5, Chapter 9. 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). 1.3 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. 1.4 Where automated equipment forms part of an integrated semi-automatic observing system, displays of data which are made available to the local air traffic services 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 WMO. Note. — The METAR and SPECI code forms are contained in the Manual on Codes (WMO-No. 306), Volume I.1, Part A — Alphanumeric Codes. 2.1.3 METAR and SPECI shall be disseminated in IWXXM 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). Issue: 3.00 APP 3-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports Note 2. — Geography markup language (GML) is an encoding standard of the Open Geospatial Consortium (OGC). 2.2 Use of CAVOK 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 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 4.2.4.4. Note 2. — The lowest visibility is reported in accordance with 4.2.4.4 a). b) no cloud of operational significance; c) no weather of significance to aviation as given in 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. 2.3.2 Where required in accordance with Chapter 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; Issue: 3.00 APP 3-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports c) when the variation from the mean surface wind speed (gusts) has changed 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 Chapter 4, 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 the operators concerned, considering 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, 1 500 or 3 000 m; and 2. 5 000 m, in cases where significant numbers of flights are operated in accordance with the visual flight rules; Note 1. — In local special reports, visibility refers to the value(s) to be reported in accordance with 4.2.4.2 and 4.2.4.3; in SPECI, visibility refers to the value(s) to be reported in accordance with 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 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 Issue: 3.00 APP 3-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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: — duststorm — 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 (1 500 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 1 000 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 3.1 METAR and SPECI 3.1.1 METAR and SPECI 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. 3.1.2 METAR and SPECI shall be disseminated to other aerodromes in accordance with regional air navigation agreement. Issue: 3.00 APP 3-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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 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 agreed 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. 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. Issue: 3.00 APP 3-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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 reports, local special reports, METAR, SPECI and 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 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 reports, local special reports, 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 which 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 reports, local special reports, 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 Issue: 3.00 APP 3-6 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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: 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 Issue: 3.00 APP 3-7 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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 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 reports, local special reports, 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 kilometre steps when it is 5 km or more but less than 10 km; and as 10 km when it 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: Issue: 3.00 APP 3-8 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports a) if the visibility is observed from more than one location along the runway as specified in Chapter 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 Chapter 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 1 500 m or 2) less than 50 percent of the prevailing visibility and less than 5 000 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 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 1 000 to 1 500 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 transmissometers 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). Issue: 3.00 APP 3-9 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 4.3.2.1 Instrumented systems based on transmissometers 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 transmissometers 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. 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 175 m. 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 a 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 a 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 Issue: 3.00 APP 3-10 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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 reports, local special reports, METAR and SPECI, the runway visual range shall be reported in steps of 25 m when it 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 it 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. 4.3.6.2 Fifty metres should be considered the lower limit and 2 000 metres the upper limit for runway visual range. Outside of these limits, local routine reports, local special reports, METAR and SPECI should merely indicate that the runway visual range is less than 50 m or more than 2 000 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 Issue: 3.00 APP 3-11 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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 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 reports, local special reports, 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 and/or snow pellets GS Issue: 3.00 APP 3-12 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports — Reported when diameter of largest hailstones is less than 5 mm. b) Obscurations (hydrometeors) Fog FG — Reported when visibility is less than 1 000 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 1 000 m but not more than 5 000 m. c) Obscurations (lithometeors) — The following shall be used only when the obscuration consists predominantly of lithometeors and the visibility is 5 000 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 d) Other phenomena Dust/sand whirls (dust devils) PO Squall SQ Funnel cloud (tornado or waterspout) FC Dust storm DS Sandstorm SS 4.4.2.4 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. 4.4.2.5 In local routine reports, local special reports, 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 Issue: 3.00 APP 3-13 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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” shall be used without qualification. Freezing FZ — Supercooled 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). 4.4.2.6 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. Shallow MI — Less than 2 m (6 ft) above ground level. Patches BC — Fog patches randomly covering the aerodrome. Partial PR Issue: 3.00 APP 3-14 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports — A substantial part of the aerodrome covered by fog while the remainder is clear. 4.4.2.7 In automated 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 should not be characterized by SH. 4.4.2.8 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. 4.4.2.9 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 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. 4.4.2.10 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 Issue: 3.00 APP 3-15 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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 3 000 m (10 000 ft). 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 (10 000 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 (2 000 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 (2 000 ft); Issue: 3.00 APP 3-16 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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 shall 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. 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”; c) when cumulonimbus clouds or towering cumulus clouds are detected by the automatic observing system and the cloud amount and/or the height of cloud base cannot be observed, the cloud amount and/or the height of cloud base should be replaced by “///”; and Issue: 3.00 APP 3-17 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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 reports, local special reports, 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 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 hectopascals and reported therein in steps of whole hectopascals, using four digits. Any observed value which does not fit the reporting scale in use shall be rounded down to the nearest lower whole hectopascal. 4.7.3.2 In local routine and special reports: a) QNH shall be included; Issue: 3.00 APP 3-18 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports b) QFE shall be included if required by users or as agreed between the meteorological authority, the appropriate ATS authority 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: — freezing precipitation — moderate or heavy precipitation (including showers thereof) — blowing snow — duststorm, sandstorm — thunderstorm — funnel cloud (tornado or waterspout) — 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 Issue: 3.00 APP 3-19 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports — duststorm, sandstorm DS, SS — blowing snow BLSN — funnel cloud (tornado or waterspout) 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 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 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 — Alphanumeric Codes, Code Table 3700. 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 local routine and special reports are shown in Table A3-4 of this appendix. Issue: 3.00 APP 3-20 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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) Issue: 3.00 APP 3-21 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports Issue: 3.00 APP 3-22 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports Issue: 3.00 APP 3-23 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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). 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 reports only. 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 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 groups. Issue: 3.00 APP 3-24 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports Table A3-2. Template for METAR and SPECI 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 are shown in Table A3-5 of this appendix. Note 2.— The explanations for the abbreviations can be found in the PANS-ABC (Doc 8400). Issue: 3.00 APP 3-25 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports Issue: 3.00 APP 3-26 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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. Issue: 3.00 APP 3-27 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports 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 groups. Table A3-3. Use of change indicators in trend forecasts Issue: 3.00 APP 3-28 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports Table A3-4. Ranges and resolutions for the numerical elements included in local reports Issue: 3.00 APP 3-29 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports Table A3-5. Ranges and resolutions for the numerical elements included in METAR and SPECI Issue: 3.00 APP 3-30 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports Example A3-1. Routine Report Issue: 3.00 APP 3-31 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 3 — Technical Specifications Related to Meteorological Observations and Reports Example A3-2. Special Report Example A3-3. Volcanic activity report Issue: 3.00 APP 3-32 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 4 — Technical Specifications Related to Aircraft Observations and Reports APPENDIX 4 TECHNICAL SPECIFICATIONS RELATED TO AIRCRAFT OBSERVATIONS AND REPORTS (See Chapter 5 of this MCAR.) 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 - contract (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 Chapter 13 and the SSR Mode S message format is specified in ICAO Annex 10, Volume III, Part I, Chapter 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 Issue: 3.00 APP 4-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 4 — Technical Specifications Related to Aircraft Observations and Reports - Time - Flight level or altitude - Next position and time over - Ensuing significant point 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 ICAO Annex 10, Volume III, Part I. 1.2 Special air-reports by air-ground data link 1.2.1 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) Issue: 3.00 APP 4-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 4 — Technical Specifications Related to Aircraft Observations and Reports - 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. 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 of 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 Issue: 3.00 APP 4-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 4 — Technical Specifications Related to Aircraft Observations and Reports 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. 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 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 2.6.2.1 Turbulence shall be considered: a) severe when the peak value of EDR equals or exceeds 0.45; b) moderate when the peak value of EDR is equal to or above 0.20 and below 0.45; c) light when the peak value of EDR is above 0.10 and below 0.20; and d) nil when the peak value of EDR is below or equal to 0.10. 2.6.3 Special air-reports 2.6.3.1 Special air-reports on turbulence shall be made during any phase of the flight whenever the peak value of EDR equals or exceeds 0.20.

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 reported in terms of EDR. Special air-reports shall be issued every minute until such time as the peak values of EDR fall below 0.20. 2.7 Humidity 2.7.1 The humidity shall be reported as the relative humidity, rounded to the nearest whole per cent. Note. — The ranges and resolutions for the meteorological elements included in air-reports are shown in Table A4-3. Issue: 3.00 APP 4-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 4 — Technical Specifications Related to Aircraft Observations and Reports 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 the world area forecast WAFCs and the centres 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 volcanic ash advisory centres. 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 flight is in Appendix 6, Table A6-1B. 3.2 Responsibilities of world area forecast centres: Air-reports received at WAFCs shall be further disseminated as basic meteorological data. Note. — The dissemination of basic meteorological data is normally carried out on the World Meteorological Organization (WMO) Global Telecommunication System. 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. 4.2 Post-flight reporting of volcanic activity Issue: 3.00 APP 4-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 4 — Technical Specifications Related to Aircraft Observations and Reports 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. 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). Issue: 3.00 APP 4-6 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 4 — Technical Specifications Related to Aircraft Observations and Reports 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. Table A4-2. Time of occurrence of the peak value to be reported Table A4-3. Ranges and resolutions for the meteorological elements included in air-reports Issue: 3.00 APP 4-7 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts APPENDIX 5 TECHNICAL SPECIFICATIONS RELATED TO FORECASTS (See Chapter 6 of this Annex.) 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 the Manual on Codes (WMO-No. 306), Volume I.1, Part A — Alphanumeric Codes. 1.1.2 TAF shall be disseminated in IWXXM GML form in addition to the dissemination of the TAF in accordance with 1.1.1. Note 1. — 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). Note 2. — Geography markup language (GML) is an encoding standard of the Open Geospatial Consortium (OGC). 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 should 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 when conditions of CAVOK are forecast to apply. The prevailing visibility should be Issue: 3.00 APP 5-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts 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 1.2.3.1 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 - duststorm - sandstorm - thunderstorm (with or without precipitation) - squall - funnel cloud (tornado or waterspout) - other weather phenomena given in Appendix 3 Para 4.4.2.3, as agreed by the meteorological authority with the appropriate ATS authority and the operators concerned. 1.2.3.2 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 should 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 should 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 forecast and not already included under a) to c). Issue: 3.00 APP 5-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts 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” should be used. 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 - duststorm - 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 the 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; Issue: 3.00 APP 5-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts 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, 1 500 or 3 000 m; or 2. 5 000 m in cases where significant numbers of flights are operated in accordance with the visual flight rules; 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 1 000 ft); or 2. 450 m (1 500 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 (1 500 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 1 000 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 Chapter 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” should 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 Issue: 3.00 APP 5-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts 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 should 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 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 should be subdivided into self-contained periods using the abbreviation “FM” followed immediately by a six-figure time group in days, 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 1.4.1 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 should 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 1.5.1 The number of change and probability groups should be kept to a minimum and should not normally exceed five groups. Issue: 3.00 APP 5-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts 1.6 Dissemination of TAF 1.6.1 TAF and amendments thereto 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 2.1.1 Trend forecasts shall be issued in accordance with the templates shown in Appendix 3, Table 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. 2.2 Inclusion of meteorological elements in trend forecasts 2.2.1 General provisions 2.2.1.1 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 2.2.2.1 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 the 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 of typical aircraft operating at the aerodrome. 2.2.3 Visibility 2.2.3.1 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 deteriorate and pass through one or more of the following values: 150, 350, 600, 800, 1500 or 3000 Issue: 3.00 APP 5-6 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts 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) - duststorm - sandstorm - other weather phenomena given in Appendix 3, 4.4.2.3, as agreed by the meteorological authority with the 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 2.2.5.1 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, 1 000 and 1 500 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 (1 500 ft), the trend forecast shall also indicate changes in cloud amount from FEW, or SCT increasing to BKN or OVC, or changes from BKN Issue: 3.00 APP 5-7 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts or OVC decreasing to FEW or SCT. When no clouds of operational significance are forecast and “CAVOK” is not appropriate, the abbreviation “NSC” shall be used. 2.2.6 Vertical visibility 2.2.6.1 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 300m (100, 200, 500 or 1000 ft), the trend forecast shall indicate the change. 2.2.7 Additional criteria 2.2.7.1 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(s) concerned. 2.3 Use of change groups Note. — Guidance on the use of change indicators in trend forecasts is given in Appendix 3, 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, Issue: 3.00 APP 5-8 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts 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 the abbreviations “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 temporary fluctuations 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 shall be 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 indicator: 2.4.1 The indicator “PROB” shall not be used in trend forecasts. 3 Criteria related to forecasts 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 to 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 forecasts for low level flights 4.1 Format and content of GAMET area forecasts 4.1.1 When prepared in GAMET format, area forecasts shall contain two sections: Section I related to information on en-route weather phenomena hazardous to low-level flights, prepared in support of the issuance of AIRMET information, and Section II related to additional information required by low-level flights. The content and order of elements in a GAMET area forecast, when prepared, shall be Issue: 3.00 APP 5-9 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts in accordance with the template shown in Table A5-3. Additional elements in Section II shall be included in accordance with regional air navigation agreement. Elements which are already covered by a SIGMET message shall be omitted from GAMET area forecasts. 4.2 Amendments to GAMET area forecasts 4.2.1 When a weather phenomenon hazardous to low-level flights has been included in the GAMET area forecast and the phenomenon forecast does not occur, or is no longer forecast, a GAMET AMD shall be issued, amending only the weather element concerned. Note. — Specifications regarding the issuance of AIRMET information amending the area forecast in respect of weather phenomena hazardous for low-level flights are given in APPENDIX 6. 4.3 Content of area forecasts for low-level flights in chart form 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). 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. Note. — Guidance on the use of terms “ISOL”, “OCNL” and “FRQ” referring to cumulonimbus and towering cumulus clouds, and thunderstorms is given in Appendix 6. 4.4 Exchange and dissemination of area forecasts for low-level flights 4.4.1 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 Area forecasts for low-level flights, in support of 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. Issue: 3.00 APP 5-10 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts 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). Issue: 3.00 APP 5-11 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts Notes. — 1. Fictitious location. 2. To be used in accordance with 1.2.1. 3. To be included in accordance with 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). Issue: 3.00 APP 5-12 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts 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 Table A5-3. Template for GAMET Key: = M = inclusion mandatory, part of every message; C = inclusion conditional, dependent on meteorological conditions; O = inclusion optional; = = a double line indicates that the text following it should be placed on the subsequent line. Issue: 3.00 APP 5-13 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts Issue: 3.00 APP 5-14 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts Notes. — 1. Fictitious location. 2. Free text describing well-known geographical locations should be kept to a minimum. 3. The location of the CB and/or TCU should be specified in addition to any widespread areas of broken or overcast cloud as given in the example. 4. List as necessary, with comma separating. 5. When no elements are included in Section I. Issue: 3.00 APP 5-15 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts Table A5-4. Ranges and resolutions for the numerical elements included in TAF Example A5-1. TAF Issue: 3.00 APP 5-16 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts Example A5-2. Cancellation of TAF Example A5-3. GAMET area forecast Issue: 3.00 APP 5-17 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 5 — Technical Specifications Related to Forecasts Issue: 3.00 APP 5-18 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts APPENDIX 6 TECHNICAL SPECIFICATIONS RELATED TO SIGMET AND AIRMET INFORMATION, AERODROME WARNINGS AND WIND SHEAR WARNINGS AND ALERTS (See Chapter 7 of this MCAR) Note. — Data type designators to be used in abbreviated headings for SIGMET, AIRMET, tropical cyclone and volcanic ash advisory messages are given in the Manual on the Global Telecommunication System (WMO-No. 386). 1 Specification 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 A6-1, only one of the following phenomena shall be included in a SIGMET message, using the abbreviations as indicated below: 1.1.4.1 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 Issue: 3.00 APP 6-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts - embedded with hail EMBD TSGR - frequent, with hail FRQ TSGR - squall line with hail SQL TSGR tropical cyclone - tropical cyclone with 10-minute TC (+ cyclone name) mean 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 duststorm - heavy duststorm 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 SIGMET information shall be disseminated in IWXXM GML form in addition to the dissemination of SIGMET information in accordance with 1.1.1. Issue: 3.00 APP 6-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Note 1. — 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). Note 2. — Geography markup language (GML) is an encoding standard of the Open Geospatial Consortium (OGC). 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 volcanic ash advisory centres. 1.2.2 SIGMET messages 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 Specifications related to AIRMET information 2.1 Format of AIRMET messages: 2.1.1 The content and order of elements in an AIRMET message shall be in accordance with the template shown in Table A6-1A. 2.1.2 The sequence number referred to in the template in Table A6-1 shall correspond with the number of AIRMET messages issued for the FIR since 0001 UTC on the day concerned. The meteorological watch offices whose area of responsibility encompasses more than one FIR and/or CTA shall issue separate AIRMET messages for each FIR and/or CTA within their area of responsibility. 2.1.3 The FIR shall be divided in sub-areas, as necessary. 2.1.4 In accordance with the template in Table A6-1A, only one of the following phenomena shall be included in an AIRMET message, using the abbreviations as indicated below: Issue: 3.00 APP 6-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts 2.1.4.1 At cruising levels below flight level 100 (or below flight level 150 in mountainous areas, or higher, where necessary): surface wind speed - widespread mean surface SFC WIND wind speed above 15 m/s (30 kt) (+ wind speed, direction and units) surface visibility - widespread areas affected SFC VIS by reduction of visibility to less (+ visibility) than 5000m, including the weather (+ one of the following weather phenomenon causing the reduction phenomena or combinations of visibility: thereof: BR, DS, DU, DZ, FC, FG, FU, GR, GS, HZ, IC, PL, PO, RA, SA, SG, SN, SQ, SS or VA) thunderstorms - isolated thunderstorms without hail ISOL TS - occasional thunderstorms without hail OCNL TS - isolated thunderstorms without hail ISOL TSGR - occasional thunderstorms without hail OCNL TSGR mountain obscuration - mountains obscured MT OBSC cloud - widespread areas of broken or overcast cloud with height of base less than 300 m (1 000 ft) above ground level: – broken BKN CLD (+ height of the base and top and units) – overcast OVC CLD (+ height of the base and top and units) - cumulonimbus clouds which are: – isolated ISOL CB – occasional OCNL CB – frequent FRQ CB - towering cumulus clouds which are: – isolated ISOL TCU – occasional OCNL TCU Issue: 3.00 APP 6-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts – frequent FRQ TCU icing - moderate icing (except for MOD ICE icing in convective clouds) turbulence - moderate turbulence (except for MOD TURB turbulence in convective clouds) mountain wave - moderate mountain wave MOD MTW 2.1.5 AIRMET information shall not contain unnecessary descriptive material. In describing the weather phenomena for which the AIRMET is issued, no descriptive material additional to that given in 2.1.4 shall be included. AIRMET information concerning thunderstorms or cumulonimbus clouds shall not include references to associated turbulence and icing. Note. — The specifications for SIGMET information which is also applicable to low-level flights are given in 1.1.4. 2.1.6 AIRMET information shall be disseminated in IWXXM GML form in addition to the dissemination of AIRMET information in accordance with 2.1.1. Note 1. — 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). Note 2. — Geography markup language (GML) is an encoding standard of the Open Geospatial Consortium (OGC). 2.2 Dissemination of AIRMET messages: 2.2.1 AIRMET messages should be disseminated to meteorological watch offices in adjacent FIRs and to other meteorological watch offices or aerodrome meteorological offices, as agreed between the meteorological authorities concerned. 2.2.2 AIRMET messages should be transmitted to international operational meteorological databanks and the centres designated by regional air navigation Issue: 3.00 APP 6-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts agreement for the operation of aeronautical fixed service Internet-based services, in accordance with regional air navigation agreement. 3 Specifications related to special air-reports Note. — This Appendix deals with the uplink of special air-reports. The general specifications related to special air reports are given in Appendix 4 3.1 Special air-reports should be uplinked for 60 minutes after their issuance. 3.2 Information on wind and temperature included in automated special air-reports should not be uplinked to other aircraft in flight. 4 Detailed criteria related to SIGMET and AIRMET messages and special air- reports (UPLINK): 4.1 Identification of the flight information region: 4.1.1 In cases where the airspace is divided into an 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 and 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; 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 Issue: 3.00 APP 6-6 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts 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 when the peak value of EDR equals or exceeds to 0.45; and b) moderate when the peak value of EDR is equal to or above 0.20 and below to 0.45. 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/duststorm 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. Issue: 3.00 APP 6-7 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts 5 Specification 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 - freezing precipitation - 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. Issue: 3.00 APP 6-8 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts 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 5.2.1 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 of the concerned. 6 Specifications related to wind shear warnings 6.1 Detection of wind shear 6.1.1 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 Chapter 5; or d) other meteorological information, for example, from appropriate sensors located on existing masts or towers in the vicinity of the aerodrome or nearby 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 - frontal surfaces Issue: 3.00 APP 6-9 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts - 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 Appendix 3, 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. Note1. — 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. Issue: 3.00 APP 6-10 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts 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-sensing equipment 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. Issue: 3.00 APP 6-11 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Table A6-1A. Template for SIGMET and AIRMET messages 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. Issue: 3.00 APP 6-12 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Issue: 3.00 APP 6-13 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Issue: 3.00 APP 6-14 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Issue: 3.00 APP 6-15 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Issue: 3.00 APP 6-16 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Issue: 3.00 APP 6-17 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts 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". 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. 26. The elements “forecast time” and “forecast position” are not to be used in conjunction with the element “movement or expected movement”. 27. 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). 31. The term CB is to be used when the forecast position for the cumulonimbus cloud is included. 32. 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. Issue: 3.00 APP 6-18 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts 33. For SIGMET messages for radioactive cloud, only within (WI) is to be used for the elements “location” and “forecast position”. 34. 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 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 are shown in Table A6-4 of this appendix. Notes. — Issue: 3.00 APP 6-19 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts 1. No wind and temperature to be uplinked to other aircraft in flight in accordance with 3.2. 2. See 3.1. 3. Fictitious call sign. 4. In the case of special air-report for volcanic ash cloud, the vertical extent (if observed) and name of the volcano (if known) can be used. 5. Fictitious location. Issue: 3.00 APP 6-20 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Table A6-2. Template for aerodrome warnings 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). 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). Issue: 3.00 APP 6-21 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Table A6-3. Template for wind shear warnings 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). Notes. — 1. Fictitious location. 2. Additional provisions in 6.2.3. 3. End of the message (as the wind shear warning is being cancelled). Issue: 3.00 APP 6-22 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Table A6-4. Ranges and resolutions for the numerical elements included in volcanic ash and tropical cyclone advisory messages, SIGMET/AIRMET messages and aerodrome and wind shear warnings. Example A6-1. SIGMET and AIRMET message and the corresponding cancellations. Issue: 3.00 APP 6-23 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Example A6-2. SIGMET message for tropical cyclone Example A6-3. SIGMET message for volcanic ash Issue: 3.00 APP 6-24 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 6 — Technical Specifications Related to SIGMET and AIRMET Information, Aerodrome Warnings and Wind Shear Warnings and Alerts Example A6-4. SIGMET message for radioactive cloud Example A6-5. SIGMET message for severe turbulence Example A6-6. AIRMET message for moderate mountain wave Issue: 3.00 APP 6-25 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 7 — Technical Specifications Related to Aeronautical Climatological Information APPENDIX 7 TECHNICAL SPECIFICATIONS RELATED TO AERONAUTICAL CLIMATOLOGICAL INFORMATION (See Chapter 8 of this MCAR) 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 3.2.1 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; Issue: 3.00 APP 7-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 7 — Technical Specifications Related to Aeronautical Climatological Information 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 at specified 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 the Technical Regulations (WMO-No. 49), Volume II — Meteorological Service for International Air Navigation, Part III. Issue: 3.00 APP 7-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 8 — Technical Specifications Related to Service for Operators and Flight Crew Members APPENDIX 8 TECHNICAL SPECIFICATIONS RELATED TO SERVICE FOR OPERATORS AND FLIGHT CREW MEMBERS (See Chapter 9 of this MCAR) 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 Maldives Meteorological Service, 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 replanning 2.1 Format of upper-air gridded information Issue: 3.00 APP 8-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 8 — Technical Specifications Related to Service for Operators and Flight Crew Members 2.1.1 Upper-air gridded information supplied by WAFCs for pre-flight and in-flight replanning shall be in the GRIB code form. Note. — The GRIB code form is contained in the 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 and in-flight re-planning shall be in the BUFR code form. Note. — The BUFR code form is contained in the Manual on Codes (WMO-No 306), Volume I.2, Part B — Binary Codes. 2.2.2 In addition to 2.2.1, information on significant weather supplied by WAFCs for pre- flight planning and in-flight replanning 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 2.3.1 Meteorological information for pre-flight 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 3.1.1 The material displayed should be readily accessible to the flight crew members or other flight operations personnel concerned. 4 Specification related to flight documentation 4.1 Presentation of information Issue: 3.00 APP 8-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 8 — Technical Specifications Related to Service for Operators and Flight Crew Members 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. For low-level flights, alternatively, GAMET area forecasts shall be used. 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 World Meteorological Organization (WMO) on the basis of relevant operational requirements stated by the International Civil Aviation Organization. 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, GAMET, SIGMET and AIRMET, volcanic ash, tropical cyclone and space weather 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. Where appropriate, approved abbreviations should be used. The units employed for each element should be indicated; they should be in accordance with MCAR 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 Issue: 3.00 APP 8-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 8 — Technical Specifications Related to Service for Operators and Flight Crew Members route lengths and the amount of detail that needs to be given in the charts as agreed between the meteorological authorities and the 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 or, for non- 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; and d) 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 1:15x106 as required. 4.2.2 Set of charts to be provided Issue: 3.00 APP 8-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 8 — Technical Specifications Related to Service for Operators and Flight Crew Members 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 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. 4.2.3 Height indications 4.2.3.1 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 4.3.1.1 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 and AIRMET 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 4.3.2.1 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: Issue: 3.00 APP 8-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 8 — Technical Specifications Related to Service for Operators and Flight Crew Members a) SIGMET and AIRMET 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 systems for briefing, consultation, flight planning and flight documentation 5.1 Access to the systems 5.1.1 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 5.2.1 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 WMO, or based on a menu-driven user interface, or other appropriate mechanisms as agreed between the meteorological authority and the 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 WMO Publication No. 386, Manual on the Global Telecommunication System. 6 Specifications related to information for aircraft in flight 6.1 Supply of information requested by an aircraft in flight Issue: 3.00 APP 8-6 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 8 — Technical Specifications Related to Service for Operators and Flight Crew Members 6.1.1 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 operator 6.2.1 Meteorological 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 and AIRMET information and special air-reports 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 Doc 8896. Issue: 3.00 APP 8-7 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 8 — Technical Specifications Related to Service for Operators and Flight Crew Members Figure A8-1 Fixed areas of coverage of WAFS forecasts in chart form — Mercator projection Issue: 3.00 APP 8-8 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 8 — Technical Specifications Related to Service for Operators and Flight Crew Members Figure A8-2 Fixed areas of coverage of WAFS forecasts in chart form — Polar stereographic projection (northern hemisphere) Issue: 3.00 APP 8-9 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 8 — Technical Specifications Related to Service for Operators and Flight Crew Members Figure A8-3 Fixed areas of coverage of WAFS forecasts in chart form — Polar stereographic projection (southern hemisphere) Issue: 3.00 APP 8-10 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 9 —Technical Specifications Related to Information for Air Traffic Services, Search and Rescue Services and Aeronautical Information Services APPENDIX 9 TECHNICAL SPECIFICATIONS RELATED TO INFORMATION FOR AIR TRAFFIC SERVICES, SEARCH AND RESCUE SERVICES AND AERONAUTICAL INFORMATION SERVICES (See Chapter 10 of this MCAR) 1 Information to be provided for air traffic services units 1.1 List of information for the aerodrome control tower 1.1.1 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 and AIRMET 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, as agreed between the meteorological and ATS authorities concerned; 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 1.2.1 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 and AIRMET information, wind shear warnings and alerts and appropriate special air-reports for the airspace with which the approach control unit is concerned and aerodrome warnings; c) any additional meteorological information agreed upon locally; 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; and Issue: 3.00 APP 9-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 9 —Technical Specifications Related to Information for Air Traffic Services, Search and Rescue Services and Aeronautical Information Services e) 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 and flight information centre 1.3.1 The following meteorological information shall be supplied, as necessary, to an area control centre or a flight information centre by its associated 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 (FIR) or the control area (CTA) 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 and AIRMET 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 flight information centre or area control centre to meet requests from aircraft in flight; if the information requested is not available in the associated meteorological watch office, 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 material into the atmosphere, as agreed between the meteorological and ATS authorities concerned; f) tropical cyclone advisory information issued by a tropical cyclone advisory centre in its area of responsibility; g) volcanic ash advisory information issued by a volcanic ash advisory centre in its area of responsibility; and h) information received on pre-eruption volcanic activity and/or a volcanic eruption as agreed between the meteorological and ATS authorities concerned. 1.4 Supply of information to aeronautical telecommunications stations Issue: 3.00 APP 9-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 9 —Technical Specifications Related to Information for Air Traffic Services, Search and Rescue Services and Aeronautical Information Services 1.4.1 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 flight information centre or the area control centre. 1.5 Format of information 1.5.1 Local routine, local special reports, METAR, SPECI, TAF, trend forecasts, SIGMET and AIRMET 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 soon as is practicable after the processing of the forecasts has been completed. 2 Information to be provided for search and rescue services units 2.1 List of information 2.1.1 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 is any and ocean currents, if relevant to the search area; and g) sea-level pressure data. 2.2 Information to be provided on request Issue: 3.00 APP 9-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 9 —Technical Specifications Related to Information for Air Traffic Services, Search and Rescue Services and Aeronautical Information Services 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 services units 3.1 List of information 3.1.1 The following information shall be supplied, as necessary, to an aeronautical information services unit: a) information on meteorological service for air navigation, intended for inclusion in the aeronautical information publication(s) concerned; Note. — Details of this information are given in the Procedures for Air Navigation Services — Aeronautical Information Management (PANS-AIM, Doc 10066), 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 MCAR 15, Chapter 6.3.2.2 and 6.3.2.3; 2. the occurrence of volcanic activity; and Note. — The specific information required is given in Chapter 3, 3.3.2 and Chapter 4, 4.8. Issue: 3.00 APP 9-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 9 —Technical Specifications Related to Information for Air Traffic Services, Search and Rescue Services and Aeronautical Information Services 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 Chapter 3, 3.4.2 g). 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. Issue:

3.00 APP 9-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 10 —Technical Specifications Related to Requirements for and Use of Communications APPENDIX 10 TECHNICAL SPECIFICATIONS RELATED TO REQUIREMENTS FOR AND USE OF COMMUNICATIONS (See Chapter 11 of this MCAR) 1 Specific Requirements for Communications 1.1 Required transit times of meteorological information: 1.1.1 AFTN messages and bulletins containing operational meteorological information shall achieve transit times of less than 5 minutes, unless otherwise determined 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 between the world area forecast centre 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 2.1.1.1 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 2.1.2.1 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 Issue: 3.00 APP 10-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 10 —Technical Specifications Related to Requirements for and Use of Communications 2.1.3.1 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 the 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 2.1.4.1 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 products should 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 Issue: 3.00 APP 10-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 10 —Technical Specifications Related to Requirements for and Use of Communications 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 prescribed in Chapters 4, 6 and 7 of this MCAR. 3.1.2 The content and format of air-reports transmitted by aircraft shall be consistent with the provisions prescribed in chapter 5 of this MCAR and the Procedures for Air Navigation Services — Air Traffic Management (PANS-ATM, Doc 4444), Appendix 1. 3.2 Content and format of meteorological bulletins 3.2.1 The substance of a meteorological bulletin transmitted via the aeronautical mobile service shall remain unchanged from that contained in the bulletin as originated. 4 Use of Aeronautical Data Link Service — D-VOLMET 4.1 Detailed content of meteorological information available for D-VOLMET 4.1.1 The aerodromes for which METAR, SPECI and TAF are to be available for uplink to aircraft in flight shall be determined by regional air navigation agreement. 4.1.2 The flight information regions (FIRs) for which SIGMET and AIRMET messages are to be available for uplink to aircraft in flight shall be determined by regional air navigation agreement. 4.2 Criteria related to information to be available for D-VOLMET 4.2.1 The latest available METAR, SPECI and TAF, and valid SIGMET and AIRMET should be used for uplink to aircraft in flight. 4.2.2 TAF included in the D-VOLMET should be amended as necessary to ensure that a forecast, when made available for uplink to aircraft in flight, reflects the latest opinion of the meteorological office concerned. 4.2.3 If no SIGMET message is valid for an FIR, an indication of “NIL SIGMET” should be included in the D-VOLMET. Issue: 3.00 APP 10-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 10 —Technical Specifications Related to Requirements for and Use of Communications 4.3 Format of information to be available for D-VOLMET: 4.3.1 The content and format of reports, forecasts and SIGMET and AIRMET information included in D-VOLMET shall be consistent with the provisions prescribed in Chapters 4, 6 and 7 of this MCAR. 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 FIRs 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 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 prescribed in Chapters 4, 6 and 7 of this MCAR. 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, Issue: 3.00 APP 10-4 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 10 —Technical Specifications Related to Requirements for and Use of Communications Aeronautical Information Services and Aeronautical Meteorological Services (Doc 9377), Appendix 1. Issue: 3.00 APP 10-5 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 10 —Technical Specifications Related to Requirements for and Use of Communications APPENDIX 11 EVIDENCES (ACRONYMS/ RECORDS/ REFERENCES) +SHRA HEAVY SHOWER OF RAIN +TSSNGR : THUNDERSTORM WITH HEAVY SNOW AND HAIL ACC : AREA CONTROL CENTER ADS : AUTOMATIC DEPENDENT SURVEILLANCE AFS : AERONAUTICAL FIXED SERVICE AFTN : AERONAUTICAL FIXED TELECOMMUNICATION NETWORK AIREP : AIR REPORT AIRMET : INFORMATION CONCERNING EN-ROUTE WEATHER PHENOMENA WHICH MAY EFFECT THE SAFETY OF LOW LEVEL AIRCRAFT OPERATIONS AMD : AMENDMENT AOP : AERODROME OPERATIONAL PLANNING APM : AIRPORT MANAGER ATM : AIR TRAFFIC MANAGEMENT ATS : AIR TRAFFIC SERVICES ATSU : AIR TRAFFIC SERVICES UNIT AUTO : METAR AND SPECI FROM AUTOMATIC OBSERVING SYSTEM BECMG : BECOMING BKN : BROKEN BUFR : BINARY UNIVERSAL FORM FOR THE REPRESENTATION OF MET DATA CAT : CLEAR AIR TURBULENCE CB : CUMULONIMBUS CLOUDS CTA : CONTROL AREA EDR : EDDY DISSIPATION RATE EMBD : EMBEDDED ETOPS : ENROUTE OPERATIONS FEW : FEW FIC : FLIGHT INFORMATION CENTER FIR : FLIGHT INFORMATION REGION Issue: 3.00 APP 11-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 10 —Technical Specifications Related to Requirements for and Use of Communications FM : FROM FRQ : FREQUENT FZDZ : MODERATE FREEZING DRIZZLE FZRA : FREEZING GAMET : AREA FORECAST FOR LOW LEVEL FLIGHTS hPa : HECTOPASCAL IAVW : INTERNATIONAL AIRWAYS VOLCANO WATCH ICAO : INTERNATION CIVIL AVIATION ORGANIZATION ISA : INTERNATIONAL STANDARD ATMOSPHERE ISO : ISOLATED mb : MILIBAR MET : METEOROLOGICAL OR METEOROLOGY METAR : AERODROME ROUTINE METROLOGICAL REPORT (IN METEOROLOGICAL CODE) MOR : METEOROLOGICAL OPTICAL RANGE MSL : MEAN SEA LEVEL MWO : METEOROLOGICAL WATCH OFFICE NDV : NO DIRECTIONAL VARIATION(S) NOSIG : NO SIGNIFICANT CHANGE NSC : NO SIGNIFICANT CLOUD NSW : NO SIGNIFICANT WEATHER OCNL : OCCASIONAL OPMET : OPERATIONAL METROLOGICAL (INFORMATION) OVC : OVERCAST PANS : PROCEDURES FOR AIR NAVIGATION SERVICES PROB : PROBABILITY QFE : ATMOSPHERIC PRESSURE AT AERODROME QNH : ALTIMETER SUBSCALE SETTING TO OBTAIN ELEVATION WHEN ON THE GROUND RNAV AREA NAVIGATION RSMC : REGIONAL SPECIALIZED METEOROLOGICAL CENTRE Issue: 3.00 APP 11-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Appendix 10 —Technical Specifications Related to Requirements for and Use of Communications RVR : RUNWAY VISUAL RANGE SCT : SCATTERED SIGMET: INFORMATION CONCERNING EN-ROUTE WEATHER PHENOMENA WHICH MAY AFFECT THE SAFETY OF AIRCRAFT OPERATIONS SIGWx : SIGNIFICANT WEATHER PHENOMENA SLOL : ISOLATED (31) SNRA : MODERATE SNOW AND RAIN SPECI : AERODROME SPECIAL METROLOGICAL REPORT (IN METROLOGICAL CODE) TAF : TERMINAL AERODROME FORECAST TAFOR : TERMINAL AERODROME FORECAST TCAC : TROPICAL CYCLONE ADVISORY CENTER TEMPO : TEMPORARY TL : TILL TSGR : HAIL TSSN : THUNDERSTROM WITH MODERATE SNOW VOLMET : METEOROLOGICAL INFORMATION FOR AIRCRAFT IN FLIGHT VRB : VARIABLE VV : VERTICAL VISIBILITY WAFC : WORLD AREA FORECAST CENTER WAFS : WORLD AREA FORECAST SYSTEM WMO : WORLD METEOROLOGICAL ORGANIZATION UTC : UNIVERSAL TIME COORDINATED Issue: 3.00 APP 11-3 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Attachment A – Operationally Desirable Accuracy of Measurement or Observation ATTACHMENT A OPERATIONALLY DESIRABLE ACCURACY OF MEASUREMENT OR OBSERVATION Note. — The guidance contained in this table relates to Chapter 2, 2.2 in particular to 2.2.7, and Chapter 4. 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). Issue: 3.00 ATT A-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Attachment B – Operationally Desirable Accuracy of Forecasts ATTACHMENT B OPERATIONALLY DESIRABLE ACCURACY OF FORECASTS Note 1.— The guidance contained in this table relates to Chapter 2, 2.2, in particular to 2.2.8, and Chapter 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. Issue: 3.00 ATT B-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 Meteorological Service for Air Navigation Maldives Civil Aviation Authority Attachment B – Operationally Desirable Accuracy of Forecasts Issue: 3.00 ATT B-2 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 – Meteorological Service for Air Navigation Maldives Civil Aviation Authority Attachment C - Selected Criteria Applicable to Aerodrome Reports ATTACHMENT C SELECTED CRITERIA APPLICABLE TO AERODROME REPORTS Issue: 3.00 ATT C-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 – Meteorological Service for Air Navigation Maldives Civil Aviation Authority Attachment D - Conversion of Instrumented Readings into Runway Visual Range and Visibility ATTACHMENT D CONVERSION OF INSTRUMENTED READINGS INTO RUNWAY VISUAL RANGE AND VISIBILITY (See Appendix 3, 4.3.5 of this MCAR.) 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 conversion factors 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. The agreed 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 background 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, the intensity of lights to be used for the assessment of visibility is in the vicinity of 1 000 cd. Issue: 3.00 ATT D-1 17 April 2025 Maldivian Civil Aviation Regulations MCAR-3 – Meteorological Service for Air Navigation Maldives Civil Aviation Authority Attachment D - Conversion of Instrumented Readings into Runway Visual Range and Visibility Table D-1. Illumination threshold steps Figure D-1 Relationship between the illumination threshold E (lx) and background luminance T B (cd/m2) Issue: 3.00 ATT D-2 17 April 2025