SUBPART A DEFINITIONS AND LIST OF ACRONYMS RAC-03.001 Definitions When the terms and expressions indicated below are used in these standards and recommended practices for the meteorological service for air navigation, they have the following meanings:
1. Regional air navigation agreement. An agreement approved by the Council of ICAO, normally on the recommendation of a regional air navigation meeting.
2. Aerodrome. A defined area on land or water (including any buildings, installations and equipment) intended to be used wholly or partly for the arrival, departure and surface movement of aircraft.
- a)Alternate aerodrome. An aerodrome to which an aircraft could proceed when it is impossible or inadvisable to proceed to or land at the intended landing aerodrome, and which has the necessary installations and services, has the ability to meet the performance requirements of the aircraft, and will be operational at the expected time of use. The following types of alternate aerodromes exist:
- b)Take-off alternate aerodrome. An alternate aerodrome at which an aircraft could land should this become necessary shortly after take-off and it is not possible to use the departure aerodrome.
- c)En-route alternate aerodrome. An alternate aerodrome at which an aircraft could land in the event that a diversion becomes necessary while en route.
- d)Destination alternate aerodrome. An alternate aerodrome at which an aircraft could land if it is impossible or inadvisable to land at the intended landing aerodrome.
3. Aircraft. Any machine that can derive support in the atmosphere from the reactions of the air other than the reactions of the air against the earth's surface.
4. Air-report. A report from an aircraft in flight prepared in conformity with requirements for position reporting and operational or meteorological information.
5. Runway visual range (RVR). The distance over which the pilot of an aircraft on the centre line of a runway can see the runway surface markings or the lights delineating the runway or identifying its centre line.
6. Altitude. The vertical distance of a level, point or object considered as a point, measured from mean sea level (MSL).
7. Minimum sector altitude. The lowest altitude which may be used and which will provide a minimum vertical clearance of 300 m (1 000 ft) above all objects located within an area contained within a sector of a circle of 46 km (25 NM) radius centred on a radio aid to navigation.
8. Height. The vertical distance of a level, a point or an object considered as a point, measured from a specified datum.
9. Control area. A controlled airspace extending upwards from a specified limit above the earth.
10. Appropriate ATS authority. The relevant authority designated by the State responsible for providing air traffic services (ATS) in the airspace concerned.
11. Meteorological authority. The authority which, on behalf of a Contracting State, provides or arranges for the provision of meteorological service for international air navigation.
12. ASHTAM. A NOTAM message prepared in a special series that notifies, by means of a specific format, a change of importance to aircraft operations due to the activity of a volcano, a volcanic eruption or a volcanic ash cloud.
13. Meteorological bulletin. A text comprising meteorological information preceded by an appropriate heading.
14. Rescue coordination centre. A unit responsible for promoting efficient organization of search and rescue service and for coordinating the conduct of search and rescue operations within a search and rescue region.
15. Volcanic ash advisory centre (VAAC). A meteorological centre designated by regional air navigation agreement to provide advisory information to meteorological watch offices (MWO), area control centres (ACC), flight information centres (FIC), world area forecast centres (WAFC) and international OPMET databanks, regarding the lateral and vertical extent and forecast movement of volcanic ash in the atmosphere following volcanic eruptions.
16. Tropical cyclone advisory centre (TCAC). A meteorological centre designated by regional air navigation agreement to provide advisory information to meteorological watch offices, world area forecast centres and international OPMET databanks regarding the position, forecast direction and speed of movement, central pressure and maximum surface wind of tropical cyclones.
17. Area control centre. A unit established to provide air traffic control service to controlled flights in control areas under its jurisdiction.
18. Flight information centre. A unit established to provide flight information service and alerting service.
19. World area forecast centre (WAFC). A meteorological centre designated to prepare and issue significant weather and upper-air forecasts in digital form on a global scale directly to States by appropriate means as part of the aeronautical fixed service.
20. Tropical cyclone. A generic term for a non-frontal synoptic-scale cyclone originating over tropical waters with organized convection and cyclonic wind circulation characterized by surface wind. According to the National Hurricane Center, a tropical cyclone is a non-frontal synoptic-scale warm-core system originating over tropical or subtropical waters, which has organized deep convection and a closed surface wind circulation with a well-defined centre. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and the export of heat at the low temperature of the upper troposphere. In this they differ from extratropical cyclones, which derive their energy from horizontal temperature contrasts in the atmosphere (baroclinic effects).
21. Consultation. Discussion with a meteorologist or other qualified person on the existing and/or expected meteorological conditions relating to flight operations; the discussion includes responses to questions.
22. Quality control. Part of quality management focused on fulfilling quality requirements.
23. Operational control. The authority exercised regarding the initiation, continuation, diversion or termination of a flight in the interest of the safety of the aircraft and the regularity and efficiency of the flight.
24. Gridded data in digital form. Computer-processed meteorological data for a set of regularly spaced points on a chart, for transmission from a meteorological computer to another computer in a code form suitable for use in automated systems.
25. Approach control unit. A unit established to provide air traffic control service to controlled flights arriving at, or departing from, one or more aerodromes.
26. Search and rescue services unit. A generic term meaning, as the case may be, rescue coordination centre, rescue subcentre or alerting post.
27. Air traffic services unit. A generic term meaning, as the case may be, air traffic control unit, flight information centre or air traffic services reporting office.
28. Flight documentation. Written or printed documents, including charts or forms, containing meteorological information for a flight.
29. Elevation. The vertical distance of a point or a level on or affixed to the surface of the earth, measured from mean sea level.
30. Aerodrome elevation. The elevation of the highest point of the landing area.
31. Navigation specification. A set of aircraft and flight crew requirements needed to support performance-based navigation operations within a defined airspace. There are two kinds of navigation specifications:
- a)Required navigation performance (RNP) specification. A navigation specification based on area navigation that includes the requirement for performance monitoring and alerting, designated by the prefix RNP, e.g., RNP 4, RNP APCH.
- b)Area navigation (RNAV) specification. A navigation specification based on area navigation that does not include the requirement for performance monitoring and alerting, designated by the prefix RNAV, e.g., RNAV 5, RNAV 1.
32. Aeronautical telecommunication station. A station in the aeronautical telecommunication service.
33. Aeronautical meteorological station. A station designated to make observations and meteorological reports for use in international air navigation. For the Costa Rican State, this information will be used by the Aerodrome Meteorological Office.
34. Operator. A person, organization or enterprise engaged in, or offering to engage in, aircraft operation.
35. Verbal briefing. Verbal comments on the existing and/or expected meteorological conditions.
36. Quality assurance. Part of quality management focused on providing confidence that quality requirements will be fulfilled.
37. Quality management. Coordinated activities to direct and control an organization with regard to quality.
38. AIRMET information. Information issued by a meteorological watch office concerning the actual or expected presence of specified en-route weather phenomena which may affect the safety of low-level aircraft operations and which was not already included in the forecast issued for low-level flights in the flight information region concerned or a sub-area thereof.
39. Meteorological information. Meteorological report, analysis, forecast, and any other statement relating to existing or expected meteorological conditions.
40. SIGMET information. Information issued by a meteorological watch office concerning the actual or expected occurrence of specified en-route weather phenomena which may affect the safety of aircraft operations.
41. Meteorological report. A statement of observed meteorological conditions in relation to a specified time and location.
42. Upper-air chart. A meteorological chart relating to a specified upper-air surface or layer of the atmosphere.
43. Forecast chart. A prediction of specified meteorological elements for a specified time or period and for a specified surface or portion of airspace, represented graphically on a chart.
44. Flight crew member. A licensed crew member charged with duties essential to the operation of an aircraft during a flight duty period.
45. Performance-based navigation (PBN). Area navigation based on performance requirements for aircraft operating along an ATS route, on an instrument approach procedure or in a designated airspace.
46. Area navigation (RNAV). A method of navigation which permits aircraft operation on any desired flight path within the coverage of ground- or space-based navigation aids or within the limits of the capability of self-contained aids, or a combination of these.
47. Level. A generic term relating to the vertical position of an aircraft in flight, meaning variously, height, altitude or flight level.
- b)Flight level. A surface of constant atmospheric pressure which is related to a specific pressure datum, 1 013.2 hectopascals (hPa), and is separated from other such surfaces by specific pressure intervals.
48. NOTAM: A notice distributed by means of telecommunication containing information concerning the establishment, condition or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel concerned with flight operations.
49. Cloud of operational significance. A cloud with the height of the base below 1 500 m (5 000 ft) or below the highest minimum sector altitude, whichever is greater, or a cumulonimbus cloud or a towering cumulus cloud at any height.
50. Observation (meteorological). The evaluation of one or more meteorological elements.
51. Aircraft observation. The evaluation of one or more meteorological elements made from an aircraft in flight.
52. Meteorological office. An office designated to provide meteorological service for international air navigation.
53. Aerodrome meteorological office. An office designated to provide meteorological service for aerodromes serving international air navigation.
54. Pilot-in-command. The pilot designated by the operator, or by the owner in the case of general aviation, to be in command and charged with the safe conduct of a flight.
55. Runway. A defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft.
- a)Cruising level. A level maintained during a significant portion of a flight.
- b)Flight level. A surface of constant atmospheric pressure which is related to a specific pressure datum, 1 013.2 hectopascals (hPa), and is separated from other such surfaces by specific pressure intervals.
48. NOTAM: A notice distributed by means of telecommunication containing information concerning the establishment, condition or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel concerned with flight operations.
49. Cloud of operational significance. A cloud with the height of the base below 1 500 m (5 000 ft) or below the highest minimum sector altitude, whichever is greater, or a cumulonimbus cloud or a towering cumulus cloud at any height.
50. Observation (meteorological). The evaluation of one or more meteorological elements.
51. Aircraft observation. The evaluation of one or more meteorological elements made from an aircraft in flight.
52. Meteorological office. An office designated to provide meteorological service for international air navigation.
53. Aerodrome meteorological office. An office designated to provide meteorological service for aerodromes serving international air navigation.
54. Pilot-in-command. The pilot designated by the operator, or by the owner in the case of general aviation, to be in command and charged with the safe conduct of a flight.
55. Runway. A defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft.
- a)Cruising level. A level maintained during a significant portion of a flight.
56. Operational flight plan. The operator's plan for the safe conduct of the flight, based on considerations of aircraft performance, other operating limitations and relevant expected conditions on the route to be followed and at the aerodromes concerned.
57. Operational flight planning. The planning of flight operations by an operator.
58. Human factors principles. Principles which apply to aeronautical design, certification, training, operations and maintenance and which seek safe interface between the human and other system components by proper consideration of human performance.
59. Forecast. A statement of expected meteorological conditions for a specified time or period, and for a specified area or portion of airspace.
60. GAMET area forecast. An area forecast in abbreviated plain language for low-level flights for a flight information region or a sub-area thereof, prepared by the meteorological office designated by the meteorological authority concerned and exchanged with meteorological offices in adjacent flight information regions, as agreed by the meteorological authorities concerned.
61. Reporting point. A specified geographical location in relation to which the position of an aircraft can be reported.
62. Aerodrome reference point. The designated geographical location of an aerodrome.
63. Aeronautical fixed telecommunication network (AFTN). A worldwide system of aeronautical fixed circuits provided, as part of the aeronautical fixed service, for the exchange of messages or digital data between aeronautical fixed stations having the same or compatible communications characteristics.
64. Flight information region. An airspace of defined dimensions within which flight information service and alerting service are provided.
65. Aerodrome climatological summary. A concise summary of specified meteorological elements at an aerodrome, based on statistical data.
66. Meteorological satellite. An artificial satellite which makes meteorological observations and transmits them to Earth.
67. Aeronautical fixed service (AFS). A telecommunication service between specified fixed points provided primarily for the safety of air navigation and for the regular, efficient and economical operation of air services.
68. Aeronautical mobile service (RR S1.32). A mobile service between aeronautical stations and aircraft stations, or between aircraft stations, in which survival craft stations may also participate; emergency position-indicating radiobeacon stations may also participate in this service on designated distress and emergency frequencies.
69. World area forecast system (WAFS). A world-wide system by which world area forecast centres provide aeronautical meteorological en-route forecasts in uniform and standardized formats.
70. Standard isobaric surface. An isobaric surface used on a worldwide basis to represent and analyse the conditions of the atmosphere.
71. Aerodrome climatological table. A table providing statistical data on the observed occurrence of one or more meteorological elements at an aerodrome.
72. Aerodrome control tower. A unit established to provide air traffic control service to aerodrome traffic.
73. Threshold (THR). The beginning of that portion of the runway usable for landing.
74. International airways volcano watch (IAVW). International arrangements for monitoring and providing warnings to aircraft of volcanic ash in the atmosphere.
75. Automatic dependent surveillance (ADS). A surveillance technique in which aircraft automatically provide, via a data link, data derived from on-board navigation and position-fixing systems, including aircraft identification, four-dimensional position and additional data as appropriate.
76. Visibility. For aeronautical purposes, visibility is the greater of:
- a)the greatest distance at which a black object of suitable dimensions, located near the ground, can be seen and recognized when observed against a bright background; b) the greatest distance at which lights in the vicinity of 1 000 candelas can be seen and identified against an unlit background.
- c)Prevailing visibility. The maximum value of visibility, observed in accordance with the definition of "visibility", which is reached within a circle covering at least half the horizon or at least half the surface of the aerodrome. These areas could comprise contiguous or non-contiguous sectors.
77. VOLMET. Meteorological information for aircraft in flight.
78. VOLMET broadcast. Provision, as appropriate, of current METAR, SPECI, TAF and SIGMET by means of continuous and repetitive voice broadcasts.
79. Data link VOLMET (D-VOLMET). Provision of current aerodrome routine meteorological reports (METAR) and aerodrome special meteorological reports (SPECI), aerodrome forecasts (TAF), SIGMET, special air-reports not covered by a SIGMET and, where available, AIRMET via data link.
80. Extended range operation. Any flight of an aeroplane with two turbine engines, where the flight time, from any point on the route at cruising speed (in ISA and still air conditions) with one engine inoperative, to an adequate alternate aerodrome is greater than the threshold time approved by the State of the Operator.
81. Touchdown zone. The portion of a runway, beyond the threshold, where it is intended that landing aeroplanes first contact the runway.
RAC-03.002 Acronyms a) ACC: Area control centres b) ADS: Automatic dependent surveillance c) AFTN: Aeronautical fixed telecommunication network d) ANS: Air Navigation Services e) AIP: Aeronautical Information Publication f) AIREP: Air-report g) AIS: Aeronautical information service h) AIRMET: Information concerning en-route weather phenomena that may affect the safety of low-level aircraft operations i) ATC: Air traffic control (in general) j) ATS: Air Traffic Services k) CCA: Joint advisory circular l) CTA: Control area m) CETAC: Technical Council of Civil Aviation (Consejo Técnico de Aviación Civil) n) DGAC: Directorate General of Civil Aviation (Dirección General de Aviación Civil) o) D-VOLMET: Data link VOLMET p) FIC: Flight information centres q) FIR: Flight information region r) IAVW: International airways volcano watch s) IMN: Instituto Meteorológico Nacional t) IWXXM GML: ICAO Meteorological Information Exchange Model and Geography Markup Language u) METAR: Aerodrome routine meteorological report (in meteorological code) v) MET REPORT: Local routine meteorological report (in abbreviated plain language) w) MWO: Meteorological watch office x) GAMET: Area forecast for low-level flights y) OACI: International Civil Aviation Organization (Organización de Aviación Civil Internacional) z) OMM: World Meteorological Organization (Organización Meteorológica Mundial) aa) OPMET: Operational meteorological information bb) OVSICORI: Observatorio Sismológico y Vulcanológico Nacional cc) SGC: Quality Management System (Sistema de Gestión de Calidad) dd) SPECI: Aerodrome special meteorological report (in meteorological code) ee) SPECIAL: Local special meteorological report (in abbreviated plain language) ff) SWXC: Space weather centre gg) RAC: Costa Rican Aeronautical Regulation (Regulación Aeronáutica Costarricense) hh) TAF: Aerodrome forecast (in meteorological code) ii) TCAC: Tropical cyclone advisory centre jj) UTC: Coordinated universal time kk) VAAC: Volcanic ash advisory centre ll) VONA: Volcano Observatory Notice for Aviation mm) WAFC: World area forecast centre nn) WAFS: World area forecast system RAC-03.003 Applicability and Effectiveness This RAC is applicable to the provider of Aeronautical Meteorology Services and users of aeronautical meteorological information who provide their services for any aerodrome in the entire Republic of Costa Rica.
Furthermore, this RAC contains some requirements that are specific to the volcano observer which, in the Costa Rican State, is the Observatorio Vulcanológico y Sismológico de Costa Rica (OVSICORI).
The specifications of this RAC are applicable as of its publication in the Official Gazette La Gaceta de la República de Costa Rica.
RAC-03.004 Operational Directives (See CCA RAC-03.004) The meteorology service provider must comply with the Operational Directives issued by the Dirección General de Aviación Civil that prohibit, limit, or subject to certain conditions an operation in the interest of operational safety.
SUBPART B GENERAL ASPECTS RAC-03.005 Purpose and determination of the meteorological service (a) The purpose of the meteorological service for air navigation shall be to contribute to the operational safety, regularity, and efficiency of such navigation.
(b) The aeronautical meteorological service shall be provided for every aerodrome belonging to the Costa Rican State with certification requirements. As for the meteorological service requirements for aerodromes, landing fields, and heliports with registration requirements belonging to the Costa Rican State, of private use, private for public use, or those determined by the State, involving both domestic and international flights, if any type of meteorological service exists, it shall be specified by means of letters of agreement established between IMN and DGAC. Each type of established service must follow the specifications of this regulation when applicable or the procedures established between both entities for each case.
(c) This purpose must be achieved by providing the following users: operators (explotadores), flight crew members, air traffic services units, search and rescue services units, aerodrome administrations, and others interested in the operation or development of air navigation, with the meteorological information necessary for the performance of their respective functions.
RAC-03.010 Provision of the meteorological service The Costa Rican State determined that the Instituto Meteorológico Nacional (IMN) shall provide aeronautical meteorology services. Hereinafter, this institution is referred to in this RAC as the "Meteorological Authority" or "aeronautical meteorology service provider" for all purposes of this regulation, so that it provides the meteorological service in accordance with the needs of the country's air navigation. Therefore, it must provide the Aeronautical Meteorology Service in accordance with its function, established in the Ley 5222 of its creation, which in its Article 2, subsection g) states: "g) Provide all types of information and assistance to domestic and international civil aviation, in the field of aeronautical meteorology." The Aeronautical Authority, with prior approval from the Consejo Técnico de Aviación Civil (CETAC) and the Meteorological Authority, may contract external providers for the calibration, operation, and maintenance of meteorological equipment. These providers must comply with the provisions of this RAC, the specifications indicated in the tender or in their contract, and the procedures of the aeronautical meteorology service provider.
The external provider to the DGAC and the IMN shall operate, install, or maintain meteorological stations or other equipment when contracted for that purpose. In addition, it may be contracted to operate other meteorological inputs (such as the following examples: weather radar or LIDAR) in case, by agreement with IMN, the latter cannot carry out the acquisition and proper servicing of this equipment (continuous operation, maintenance, calibrations, or others essential for the proper functioning of the equipment). All meteorological data generated by external providers shall always be managed by IMN as the country's Meteorological Authority; the procedures for receiving this data must be coordinated between DGAC and IMN so that they are complied with by the external provider.
RAC-03.015 Meteorological Authority (See CCA RAC-03.015) The Costa Rican State, through the Ley de Creación del Instituto Meteorológico Nacional 5222 of June 26, 1973, designated the Instituto Meteorológico Nacional (IMN) "as a specialized technical body, responsible for providing meteorological service to the entire country." The IMN is designated for all purposes of this RAC as the Meteorological Authority to, in its name, provide or make arrangements for the provision of the meteorological service according to the needs of the country's international and domestic air navigation.
RAC-03.020 Requirements of the meteorological authority (See CCA RAC-03.020) The aeronautical meteorology service provider shall develop training plans and programs for its personnel so that they comply with the requirements of the World Meteorological Organization (WMO) regarding qualifications, competencies, professional development, and instruction of meteorological personnel providing services for air navigation.
Likewise, it shall prepare the description of positions or posts for its aeronautical meteorological technical personnel and establish the necessary manuals, procedures, and agreements to comply with the requirements of this regulation.
RAC-03.025 Use of meteorological information The aeronautical meteorology service provider coordinates the necessary actions to maintain a close liaison between those who provide and those who use meteorological information, in all matters affecting the provision of the meteorological service for air navigation.
RAC-03.030 Establishment of a quality system The aeronautical meteorology service provider must establish and implement an adequately organized quality system comprising the procedures, processes, and resources required to provide quality management of the meteorological information it must supply to the users indicated in RAC-03.005 (c).
RAC-03.035 Quality Management of meteorological information (See CCA RAC-03.035) The quality system established in accordance with RAC-03.030 must conform to the quality assurance standards of the International Organization for Standardization (ISO) 9000 series and must be certified by an approved organization.
RAC-03.040 The quality system The quality system must provide users with the assurance that the meteorological information supplied meets the stated requirements regarding 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.
Whenever the quality system indicates that the meteorological information to be supplied to users does not meet the stated requirements, and that automatic error correction procedures are not adequate, such information shall not be provided to the users unless it is validated by the originator.
RAC-03.045 Exchange of information (See CCA RAC-03.045) Regarding the exchange of meteorological information for operational purposes, the aeronautical meteorology service provider must include in the quality system the verification and validation procedures, as well as the resources to monitor compliance with the prescribed transmission times of the specific messages and/or bulletins that need to be exchanged, and the times of their submission for transmission. The quality system must be capable of detecting and mitigating excessive transit times of received messages and bulletins.
RAC-03.050 Quality audit (See CCA RAC-03.050) The aeronautical meteorology service provider must demonstrate compliance with the quality system applied, and will therefore be audited by the Aeronautical Authority.
If it is observed that the system does not comply, the aeronautical meteorology service provider must initiate measures to determine and correct the cause. All observations made in an audit shall be based on evidence and shall be properly documented. The aeronautical meteorology service provider must comply with the scheduled times for correcting the causes of identified non-conformities.
The meteorology service provider must keep the Aeronautical Authority informed about the progress of the measures initiated to resolve non-conformities, whenever these are tasks that may span more than one period between audits. For this purpose, the aeronautical meteorology service provider must use, as a means of reporting to the Aeronautical Authority, the submission of a Corrective Action Plan (Plan de Acción Correctiva—PAC) for each detected non-conformity, and this must include completion dates. Furthermore, the Aeronautical Authority must be kept updated on the PAC implementation process and notified once the PAC is completed, whereupon the Aeronautical Authority will proceed to review and close the non-conformity.
RAC-03.055 Format of information (See CCA RAC-03.055) The meteorological information that the aeronautical meteorology service provider must provide to the users indicated in RAC-03.005 (c) shall be consistent with human factors principles and presented in a form that requires minimal interpretation by these users.
RAC-03.060 Notification by operators (explotadores) The aeronautical meteorology service provider must agree and coordinate with the operator (explotador) the minimum advance notice with which the operator (explotador) requiring meteorological service must make the notification, as well as on the notification of changes in the service.
RAC-03.065 Actions to be notified The aeronautical meteorology service provider must provide the meteorological service needed by the operator (explotador) when the latter notifies it that:
- a)new routes or new types of operations are planned; b) lasting changes must be made in regular operations; and c) other changes are planned that affect the provision of the meteorological service.
This information must contain all the details necessary for the planning of the corresponding arrangements by the aeronautical meteorology service provider. For these purposes, the Aeronautical Authority collaborates with the aeronautical meteorology service provider to establish the required conditions for providing the demanded meteorological services.
RAC-03.070 Information required The aeronautical meteorology service provider must provide the meteorological service that the operator (explotador) or a flight crew member, in consultation with the users, notified the corresponding aerodrome meteorological office of:
- a)flight schedules; b) when non-regular flights must be conducted; and c) when flights are delayed, advanced, or canceled.
RAC-03.075 Notification of individual flights Upon notification of individual flights to the aerodrome meteorological office, the aeronautical meteorology service provider must ensure that the notification provided contains the following information, although in the case of regular flights, such a requirement may be waived with respect to part or all of that information by agreement between the aerodrome meteorological office and the operator (explotador):
- a)departure aerodrome and estimated time of departure; b) destination and estimated time of arrival; c) route to be flown and estimated time of arrival at, and departure from, any intermediate aerodrome; d) the alternate aerodromes necessary to complete the operational flight plan, taken from the relevant list contained in the regional air navigation plan; e) cruising level; f) type of flight, whether under visual flight rules or instrument flight rules; g) type of meteorological information required for a flight crew member, whether flight documentation or verbal briefing or consultation; and h) time(s) at which verbal briefing, consultation, or flight documentation is required.
RAC-03.080 Aerodrome meteorological offices The aeronautical meteorology service provider must establish one or more adequate meteorological offices for the provision of the meteorological service necessary to meet the needs of international air navigation. For this purpose, the Aeronautical Authority must provide the physical space, with the conditions and facilities required for the provision of the required aeronautical meteorological service. This space must meet the necessary conditions so that aeronautical meteorological technical personnel can carry out adequate meteorological observation and the efficient communication of the agreed meteorological reports.
The aeronautical meteorology service provider, by prior agreement with the Aeronautical Authority, must designate one of its offices or assign personnel to handle consultations for meteorological information for operations to and from Category II and III aerodromes, whether for domestic or international flights, provided that the available meteorological equipment allows for the provision of information on a route or aerodrome. These consultations must be channeled through the Flight Information Center (FIC) and are conducted in the interest of the country's air safety. The details of the information provided must be established in the operational procedures of both entities.
RAC-03.085 Functions of aerodrome meteorological offices (See CCA RAC-03.085) Aerodrome meteorological offices must carry out all or some of the following functions as established, to meet the needs of flight operations at the aerodrome and provide assistance to other aerodromes as established by agreement with the Civil Aviation Authority, as defined in the following subparagraphs:
- a)prepare or obtain forecasts and other relevant information for the flights for which they are responsible; the extent of their responsibilities regarding the preparation of forecasts must be related to local availability and the use of elements for route forecasts and aerodrome forecasts received from other offices; b) prepare or obtain forecasts of local meteorological conditions; c) maintain a continuous meteorological watch at the aerodromes for which they have been designated to prepare forecasts; d) provide verbal briefings, consultations, and flight documentation to flight crew members or other flight operations personnel; e) provide other types of meteorological information to aeronautical users; f) display available meteorological information; g) exchange meteorological information with other aerodrome meteorological offices; and h) provide the information received on pre-eruption volcanic activity, volcanic eruptions, or volcanic ash clouds to the air traffic services unit, the aeronautical information services unit, and the associated meteorological watch office (MWO), as agreed between the meteorological authorities, the aeronautical information service, and the ATS concerned.
- i)The aeronautical meteorology service provider must maintain observation of possible ash clouds at the aerodromes and vicinity, for which it must develop knowledge and practical procedures, striving for the development of monitoring capabilities with high-resolution satellite images, knowledge for interpreting ash dispersion models that it receives as inputs allowing follow-up on possible trajectories of ash emissions from volcanoes. Associated with this, it must maintain communication procedures with the country's volcano observation entity, which issues the inputs on the detection of ash eruptions.
RAC-03.090 Landing forecasts The aeronautical meteorology service provider must provide landing forecasts at all aerodromes of the Costa Rican State for which this need has been determined by regional air navigation agreement.
RAC-03.095 International aerodromes not having meteorological offices In the event that an international aerodrome does not have a meteorological office located at the aerodrome, the aeronautical meteorology service provider:
- a)must designate one or more meteorological offices to provide the required meteorological information; and b) the competent authorities shall determine the means to provide such information to the aerodromes concerned.
SUBPART C WORLD SYSTEMS, SUPPORT CENTERS, AND METEOROLOGICAL OFFICES RAC-03.100 Coordination of the meteorological service provider with the volcanic ash advisory center (VAAC) (See CCA.RAC-03.100) The aeronautical meteorology service provider must have established a procedure for receiving the service it obtains from the office that, by regional air navigation agreement, has the responsibility of VAAC within the framework of volcano monitoring on international airways, so that notifications from and to that center respond to a notification of eruption or expected eruption of a volcano or presence of volcanic ash in its area of responsibility, and that it has the best inputs that the State can facilitate.
RAC-03.105 Volcano observatories of the States (See CCA RAC-03.105) Through the Comisión Nacional de Emergencias, the Costa Rican State ensures that as long as there are active or potentially active volcanoes, it will have volcano observation entities in the country, which will have the duty to provide monitoring and observation of pre-eruption volcanic activity, volcanic eruptions, or volcanic ash clouds, such as:
- a)significant volcanic activity prior to the eruption or its cessation; b) a volcanic eruption or its cessation; and/or c) volcanic ash in the atmosphere, And they must forward this information as quickly as possible to their associated ACC/FIC, the MWO, and the VAAC, being that they must supplement their information with that from ash models.
Pre-eruption volcanic activity means in this context unusual or increasing volcanic activity that could presage a volcanic eruption.
RAC-03.110 Atmospheric data for ash dispersion modeling The aeronautical meteorology service provider must establish an operational agreement with the country's volcano observation entity to issue wind pattern data, among other atmospheric variables that the country's volcano observation entity requires as part of the inputs for ash dispersion modeling necessary for the aeronautical information services (AIS) to issue the ASHTAM.
The aeronautical meteorology service provider must notify detected changes in severity or improvement of atmospheric conditions that may affect the movement of volcanic eruptions detected by the country's volcano observation entity.
In the event of volcanic eruptions reported by the country's volcano observation entity, the aeronautical meteorology service provider must issue new wind data when a change in the wind pattern has been estimated from the one sent during the day for the development of the ash dispersion model.
RAC-03.115 Functions of the meteorology service in monitoring volcanic activity reports The aeronautical meteorology service provider shall maintain a 24-hour watch for reports and/or advisories of volcanic activity provided by the country's volcano observation entity, VAAC, or air operators (operadores aéreos).
The aeronautical meteorology service provider must take the necessary steps to ensure it receives the following inputs from the tropical cyclone advisory center (TCAC):
- a)monitoring of the evolution of tropical cyclones in its area of responsibility, using data from geostationary and polar-orbiting satellites, radar data, and other meteorological information; b) advisory information in abbreviated plain language, concerning the position of the center of the cyclone, its direction and speed of movement, central pressure, and maximum surface wind near the center, when necessary, but at least every six hours.
- c)The aeronautical meteorology service provider must ensure that its aerodrome meteorological offices receive the information issued by the TCAC and that this is received in abbreviated plain language, advisory information concerning the position of the center of the cyclone, its direction and speed of movement, central pressure, and maximum surface wind near the center, to the meteorological watch offices in its area of responsibility; d) The aeronautical meteorology service provider ensures that when the direction of the cyclone is forecast with the possibility of approaching the country, a notification is received with the greatest possible advance, and it will receive reports every 12 hours, increasing to every 3 hours if the cyclone is located less than 50 km from any coast of the country or over it.
- e)The forecast direction of the tropical cyclone is understood to be the best estimated track by the Regional TCAC (NHC Miami) on the understanding that this represents a cone of uncertainty and is frequently updated (every 3 hours) according to changes observed by monitoring and overflights carried out by the Miami National Hurricane Center, which acts as the regional entity.
RAC-03.120 Tropical cyclone advisory centers (See CCA RAC-03.120) The aeronautical meteorology service provider must take the necessary steps to ensure it receives the following inputs from the tropical cyclone advisory center (TCAC):
- a)monitoring of the evolution of tropical cyclones in its area of responsibility, using data from geostationary and polar-orbiting satellites, radar data, and other meteorological information; b) advisory information in abbreviated plain language, concerning the position of the center of the cyclone, its direction and speed of movement, central pressure, and maximum surface wind near the center, when necessary, but at least every six hours.
- c)The aeronautical meteorology service provider must ensure that its aerodrome meteorological offices receive the information issued by the TCAC and that this is received in abbreviated plain language, advisory information concerning the position of the center of the cyclone, its direction and speed of movement, central pressure, and maximum surface wind near the center, to the meteorological watch offices in its area of responsibility; d) The aeronautical meteorology service provider ensures that when the direction of the cyclone is forecast with the possibility of approaching the country, a notification is received with the greatest possible advance, and it will receive reports every 12 hours, increasing to every 3 hours if the cyclone is located less than 50 km from any coast of the country or over it.
- e)The forecast direction of the tropical cyclone is understood to be the best estimated track by the Regional TCAC (NHC Miami) on the understanding that this represents a cone of uncertainty and is frequently updated (every 3 hours) according to changes observed by monitoring and overflights carried out by the Miami National Hurricane Center, which acts as the regional entity.
RAC-03.120 Tropical cyclone advisory centers (See CCA RAC-03.120) The aeronautical meteorology service provider must ensure it has the mechanisms to receive from the space weather center (SWXC) the advisory information on space weather phenomena.
- a)monitoring of relevant terrestrial, airborne, and space-based observations, detected or predicted, when possible, regarding the existence of space weather phenomena affecting the following areas:
- 1)high-frequency (HF) radiocommunications; 2) satellite communications; 3) GNSS-based navigation and surveillance; and 4) radiation exposure at flight levels; b) The meteorology service provider must ensure it receives from the SWXC the advisory information regarding the extent, severity, and duration of the space weather phenomenon affecting the areas mentioned in subsection a) of RAC-03.125; c) The meteorology service provider must ensure that the advisory information mentioned in subsection b) of RAC-03.125 is provided to the aerodrome meteorological offices in its area of responsibility that may be affected; The meteorology service provider must know that the SWXC will maintain a 24-hour watch and in the event of an interruption in the operation of a SWXC, its functions will be carried out by another SWXC or another center designated by the State concerned providing the SWXC service.
RAC-03.125 Space weather centers (See CCA RAC-03.125) The aeronautical meteorology service provider must ensure it has the mechanisms to receive from the space weather center (SWXC) the advisory information on space weather phenomena.
- a)monitoring of relevant terrestrial, airborne, and space-based observations, detected or predicted, when possible, regarding the existence of space weather phenomena affecting the following areas:
- 1)high-frequency (HF) radiocommunications; 2) satellite communications; 3) GNSS-based navigation and surveillance; and 4) radiation exposure at flight levels; b) The meteorology service provider must ensure it receives from the SWXC the advisory information regarding the extent, severity, and duration of the space weather phenomenon affecting the areas mentioned in subsection a) of RAC-03.125; c) The meteorology service provider must ensure that the advisory information mentioned in subsection b) of RAC-03.125 is provided to the aerodrome meteorological offices in its area of responsibility that may be affected; The meteorology service provider must know that the SWXC will maintain a 24-hour watch and in the event of an interruption in the operation of a SWXC, its functions will be carried out by another SWXC or another center designated by the State concerned providing the SWXC service.
RAC-03.125 Space weather centers (See CCA RAC-03.125) SUBPART D METEOROLOGICAL OBSERVATIONS AND REPORTS RAC-03.130 Aeronautical meteorological stations and observations The aeronautical meteorology service provider shall establish at the aerodromes in its territory the aeronautical meteorological stations that it determines are necessary.
An aeronautical meteorological station may be a stand-alone station or may be combined with a synoptic station.
Aeronautical meteorological stations may include sensors installed outside the aerodrome, where the aeronautical meteorology service provider considers it justified, in order to guarantee the meteorological service for the country's air navigation.
The aeronautical meteorology service provider shall seek to keep systems updated as measurement technologies evolve over time, in a manner that facilitates the continuous improvement of the information supplied to air navigation with a view to achieving greater operational safety by identifying atmospheric systems that new technology makes it possible to locate and that pose a risk to aviation.
The Costa Rican State, through the Dirección General de Aviación Civil, may request the aeronautical meteorology service provider for a new meteorological station at a new aerodrome and in any other place in the country as required by operational safety needs and the growth of aeronautical activity. Likewise, the Dirección General de Aviación Civil, by prior agreement with the Meteorological Authority, may, through the Consejo Técnico de Aviación Civil (CETAC), contract other meteorological equipment providers for the installation, operation, and maintenance of meteorological equipment it deems necessary. Every meteorological equipment provider must establish the processes, inputs, and equipment necessary for the aeronautical meteorology service provider to receive the meteorological information obtained from this equipment, as detailed in its contract. The aeronautical meteorology service provider must perform quality controls on the information it receives from this meteorological equipment and provide this information in useful products to aeronautical users, always under the requirements of this regulation. In addition, it may use this data for all activities that the Meteorological Authority so requires.
RAC-03.135 Aeronautical meteorological stations in support of helicopter operations If necessary, the aeronautical meteorological service provider, in coordination with the civil aviation authority, may establish cooperation agreements between institutions to achieve the setting up of measurements on offshore structures or at other significant points in support of helicopter operations conducted to such structures, as stipulated by regional air navigation agreement, this because between these institutions they can bear the high costs of installation, operation, and maintenance required for atmospheric measurement in maritime environments.
RAC-03.140 Routine and special observations The aeronautical meteorological service provider must ensure that aeronautical meteorological stations carry out measurements of atmospheric variables at fixed intervals, including those used for routine observations. At aerodromes, routine observations must be supplemented by special observations when specified changes occur regarding surface wind, visibility, runway visual range, present weather, clouds, and air temperature.
RAC-03.145 Inspections, maintenance, and quality (See CCA RAC-03.145) The aeronautical meteorological service provider must ensure that aeronautical meteorological stations are inspected with sufficient frequency to ensure the maintenance of a high standard of observation quality, the correct functioning of instruments and all their indicators, and to verify that the exposure of instruments has not changed appreciably.
The aeronautical meteorological service provider must execute the operation and maintenance processes described in an Operation and Maintenance Plan for the meteorological station equipment, which must be maintained under the recommended standards to meet the quality required for air navigation.
The aeronautical meteorological service provider must maintain Operation and Maintenance logs available so that the Aeronautical Authority can verify or request the information when tasks related to air navigation oversight so require.
The aeronautical meteorological service provider must ensure that the measurement data from automatic stations receive adequate quality controls and that the sensors are maintained with the recommended calibrations.
The aeronautical meteorological service provider must send to the Aeronautical Authority reports on the statistics and quality control with the performance of the measurement data from the corresponding automatic stations, and must comply with the deadlines agreed with the Aeronautical Authority for the delivery of these reports.
RAC-03.150 Automatic meteorological equipment on runways intended for Category II and III instrument approach and landing operations (See CCA RAC-03.150) At aerodromes with runways intended for Category II and III instrument approach and landing operations, the aeronautical meteorological service provider must install, operate, and maintain automatic equipment for measuring or evaluating, as appropriate, and for monitoring and remotely indicating surface wind, visibility, runway visual range, cloud base height, air and dew point temperatures, atmospheric pressure, and vertical wind shear in support of approach, landing, and take-off operations. These devices shall be integrated automatic systems for the acquisition, processing, dissemination, and real-time display of meteorological parameters affecting landing and take-off operations. The design of the integrated automatic systems shall observe human factors principles and shall include back-up procedures.
RAC-03.155 Automatic meteorological equipment on runways intended for Category I instrument approach and landing operations (See CCA RAC-03.155) At aerodromes with runways intended for Category I instrument approach and landing operations, the aeronautical meteorological service provider must install, operate, and maintain automatic equipment for measuring or evaluating, as appropriate, and for monitoring and remotely indicating surface wind, visibility, runway visual range, cloud base height, air and dew point temperatures, atmospheric pressure, and vertical wind shear in support of approach, landing, and take-off operations. These devices must be integrated automatic systems for the acquisition, processing, dissemination, and real-time display of meteorological parameters affecting landing and take-off operations. The design of the integrated automatic systems must observe human factors principles and must include back-up procedures.
The installed automatic systems must receive all operation and maintenance requirements that ensure their correct and reliable operation. They must therefore be included in the quality management processes of the aeronautical meteorological service provider.
By agreement between the Aeronautical Authority and the aeronautical meteorological service provider, the automatic systems must receive all operation and maintenance requirements that ensure their correct and reliable operation. Data quality controls shall be performed by the aeronautical meteorological service provider.
RAC-03.160 Manual data When an integrated semi-automatic system is used for the dissemination/presentation of meteorological information, it must permit the manual insertion of data observations covering meteorological elements that cannot be observed by automatic means.
RAC-03.165 Basis for preparing reports The aeronautical meteorological service provider must ensure that observations are the basis for preparing reports to be disseminated at the aerodrome of origin and reports to be disseminated outside it.
RAC-03.170 Report accuracy (SEE CCA RAC-03.170) The aeronautical meteorological service provider must update processes, systems, and must train itself with the knowledge necessary to improve the accuracy of the reports it generates as far as technology permits.
The aeronautical meteorological service provider must endeavor to incorporate into its processes new observation and measurement technologies that allow maximizing the understanding of atmospheric systems that are hazardous to air navigation and shall ensure that these technologies are implemented in improving the accuracy of reports.
RAC-03.175 Agreement between the aeronautical meteorological service provider and the air traffic services provider (See CCA RAC-03.175) The aeronautical meteorological service provider must establish with the competent air traffic services (ATS) provider an agreement covering, among other things:
- a)the provision, in air traffic services units, of visual displays related to the integrated automatic systems; b) the calibration and maintenance of these visual displays/instruments; c) the use to be made of these visual displays/instruments by air traffic services personnel; d) when necessary, supplementary visual observations, such as with weather phenomena of operational significance in the initial climb and approach areas, in case they have been made by air traffic services personnel to update or supplement the information provided by the meteorological station; e) meteorological information obtained from the aircraft taking off or landing, such as wind shear; and f) meteorological information obtained from ground-based weather radars, which shall be supplemented with information from the most accurate publicly available atmospheric observation satellites.
RAC-03.180 Routine observations At aerodromes, the aeronautical meteorological service provider must make routine observations during the 24 hours of each day, unless otherwise agreed between the aeronautical meteorological service provider, the competent ATS authority, and the operator concerned. Such observations must be made at intervals of one hour or, if so determined by regional air navigation agreement, at intervals of half an hour. At other aeronautical meteorological stations, such observations must be made as determined by the aeronautical meteorological service provider taking into account the needs of air traffic services units and aircraft operations.
RAC-03.185 Routine reports (See CCA RAC-03.185) Reports of routine observations must 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 to other aerodromes outside the aerodrome of origin (intended mainly for flight planning, VOLMET broadcasts, and D-VOLMET).
RAC-03.190 Routine reports for aerodromes not operating 24 hours a day (See CCA RAC-03.190) The aeronautical meteorological service provider must issue the METAR before operations resume at the aerodrome, at aerodromes not in operation 24 hours a day in accordance with RAC-03.180.
RAC-03.195 Criteria regarding special observations The aeronautical meteorological service provider, in consultation with the competent air traffic services (ATS) provider, operators, and other interested parties, must establish by means of letters of agreement a list of criteria regarding special observations.
RAC-03.200 Special observation reports (See CCA RAC-03.200) Reports of special observations must 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 to other aerodromes outside the aerodrome of origin (intended mainly for flight planning, VOLMET broadcasts, and D-VOLMET) unless METAR reports are issued at half-hour intervals.
RAC-03.205 Special reports for aerodromes not operating 24 hours The aeronautical meteorological service provider must issue SPECI, as necessary, once the issuance of METAR has resumed in accordance with RAC-03.190 at aerodromes not in operation 24 hours a day.
RAC-03.210 Content of reports (See CCA RAC-03.210) Local routine and special reports and METAR and SPECI must contain the following elements in the order indicated:
- a)identification of the type of report; b) location indicator; c) time of observation; d) identification of an automated or missing report, if applicable; e) surface wind direction and speed; f) visibility; g) runway visual range, when applicable; h) present weather; i) cloud amount, cloud type (only in the case of 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 is included only in local routine and special reports).
RAC-03.215 Supplementary information In addition to the elements listed in RAC-03.210 a) to k), the supplementary information to be placed after element k) must be included in local routine and special reports and in METAR and SPECI.
RAC-03.220 Complementary information Optional elements shall be included in METAR and SPECI, as complementary information, in accordance with a regional air navigation agreement.
RAC-03.225 Surface wind (See CCA RAC-03.225) The mean direction and speed of the wind, as well as significant variations of the direction and speed thereof, must be measured and must be reported in degrees geographic and meters per second (or knots), respectively.
When local routine and special reports are used for departing aircraft, the surface wind observations for these reports must 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 must be representative of the touchdown zone.
RAC-03.235 Wind observations for one or more runways (See CCA RAC-03.235) Surface wind observations, made for METAR and SPECI must be representative of the conditions above the whole runway, in the case that there is only one runway, and above the entire set of runways when there is more than one.
RAC-03.240 Unit of measurement and reporting of visibility (See CCA RAC-03.240) Visibility must be measured or observed according to RAC-03.210, and must be reported in meters or in kilometers.
Assessments of runway visual range made in accordance with RAC-03.255 and RAC-03.260 shall be reported in meters during periods when the visibility or runway visual range is observed to be less than 1,500 m.
RAC-03.245 Reports for departing and arriving aircraft (See CCA RAC.03.245) When local routine and special reports are used for departing aircraft, the visibility observations must be representative of conditions along the RAC-03.230 Reports for departing and arriving aircraft (See CCA RAC-03.230) When local routine and special reports are used for departing aircraft, the surface wind observations for these reports must 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 must be representative of the touchdown zone.
RAC-03.235 Wind observations for one or more runways (See CCA RAC-03.235) Surface wind observations, made for METAR and SPECI must be representative of the conditions above the whole runway, in the case that there is only one runway, and above the entire set of runways when there is more than one.
RAC-03.240 Unit of measurement and reporting of visibility (See CCA RAC-03.240) Visibility must be measured or observed according to RAC-03.210, and must be reported in meters or in kilometers.
Assessments of runway visual range made in accordance with RAC-03.255 and RAC-03.260 shall be reported in meters during periods when the visibility or runway visual range is observed to be less than 1,500 m.
RAC-03.245 Reports for departing and arriving aircraft (See CCA RAC.03.245) When local routine and special reports are used for departing aircraft, the visibility observations must be representative of conditions along the RAC-03.230 Reports for departing and arriving aircraft (See CCA RAC-03.230) runway; when local routine and special reports are used for arriving aircraft, the visibility observations for these reports must be representative of the runway touchdown zone.
RAC-03.250 METAR and SPECI observation (See CCA RAC.03.250) Visibility observations made for METAR and SPECI must be representative of the aerodrome.
RAC-03.255 Runway visual range (See CCA RAC-03.255) The runway visual range shall be assessed as defined in RAC-03.150 on all runways intended for Category II and III instrument approach and landing operations.
RAC-03.260 Runways on which runway visual range shall be assessed (See CCA RAC-03.260) The runway visual range must be assessed on all runways that are foreseen to be used 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 equipped with high-intensity edge lights or runway center line lights.
RAC-03.265 Assessments of runway visual range (CCA RAC-03.265) Assessments of runway visual range must be representative of:
- a)the touchdown zone of runways intended for non-precision operations 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, c) the touchdown zone, the mid-point, and the stop end of the runway intended for Category III instrument approach and landing operations.
RAC-03.270 Operating status of automated equipment for assessing runway visual range The aeronautical meteorological service provider must inform without delay the units providing air traffic service and aeronautical information service for an aerodrome of changes in the operating status of the automated equipment used to assess runway visual range.
The manner in which these communications are made must be defined in the letters of agreement between these units.
RAC-03.275 Content of the present weather report (See CCA RAC-03.275) The aeronautical meteorological service provider must observe the present weather at the aerodrome and shall report it to the extent necessary. As a minimum, the following present weather phenomena must be identified: rain, drizzle, and freezing precipitation (including their intensity), hail, haze, mist, fog, freezing fog, and thunderstorms (including those present in the vicinity).
RAC-03.280 Present weather information at the aerodrome For local routine and special reports, the present weather information must be representative of the conditions existing at the aerodrome.
RAC-03.285 Present weather information at the aerodrome and its vicinity The present weather information for METAR and SPECI must be representative of the conditions at the aerodrome and, for any weather phenomenon present in its vicinity.
RAC-03.290 Observations of clouds Cloud amount, cloud type, and height of cloud base must be observed and must be reported, as necessary, to describe clouds of significance to operations.
When the sky is obscured, observations must be made and vertical visibility must be reported, where measured, in lieu of cloud amount, cloud type, and height of cloud base. The height of cloud base and vertical visibility must be reported in meters (or feet).
RAC-03.295 Observations of clouds at the aerodrome Observations of clouds for local routine and special reports must be representative of the runway threshold or thresholds in use.
RAC-03.300 Observations of clouds for METAR and SPECI Observations of clouds for METAR and SPECI must be representative of the aerodrome and its vicinity.
RAC-03.305 Units of measurement for air temperature and dew point (See CCA RAC-03.305) Air temperature and dew point temperature must be measured and must be reported in degrees Celsius. Observations of air temperature and dew point temperature for local routine reports, local special reports, METAR, and SPECI must be representative of the entire runway complex.
RAC-03.310 Atmospheric pressure (See CCA RAC-03.310) Atmospheric pressure must be measured, and the QNH and QFE values must be calculated and must be reported in hectopascals.
RAC-03.315 Supplementary information (See CCA RAC-03.315) Observations made at aerodromes must include available supplementary information concerning significant meteorological conditions, especially those corresponding to the approach and initial climb areas. Where possible, the information must indicate the location of the meteorological condition.
RAC-03.320 METAR and SPECI reporting from automatic observation systems (See CCA RAC-03.320) For aerodromes with automatic observation measurement systems capable of issuing METAR and SPECI, they must be used during hours when the aerodrome is not operating, and during its operating hours, as determined by the aeronautical meteorological service provider in consultation with users and based on the availability and efficient use of personnel.
RAC-03.325 Reporting of routine and special reports from automatic observation systems (See CCA RAC-03.325) For aerodromes with automatic observation measurement systems capable of issuing local routine and special reports, they must be used during the operating hours of the aerodrome, as determined by the aeronautical meteorological service provider in consultation with users and based on the availability and efficient use of personnel.
RAC-03.330 Form of reporting meteorological reports from automatic observation systems (See CCA RAC-03.330) Local routine and special reports and METAR and SPECI issued from automatic observation systems shall be identified with the word "AUTO".
RAC-03.335 Observations and reports of volcanic activity State entities responsible for volcano surveillance and monitoring must ensure that, in cases of pre-eruption volcanic activity, volcanic eruptions, and volcanic ash clouds, these are notified without delay to the Meteorological Authority, the air traffic services unit, the aeronautical information services unit, and the associated meteorological watch office. In this context, pre-eruption volcanic activity means that such activity is unusual or has increased, which could presage a volcanic eruption.
The notification must be made by means of a volcanic activity report, including the following data in the order indicated:
- a)message type, VOLCANIC ACTIVITY REPORT; b) station identifier, location indicator, or station name; c) date/time of message; d) location of volcano and name, if known; and e) concise description of the event, including, as appropriate, the level of intensity of volcanic activity, the fact of an eruption, with its date and time, and the existence in the area of a volcanic ash cloud along with the direction of its movement and its height.
The Costa Rican State shall arrange, in accordance with the provisions of this Subpart, for observations to be made by aircraft on its registry flying on international air routes, as well as the recording and reporting of such observations.
The aeronautical meteorological service provider must ensure that it receives and retransmits aircraft observations as it corresponds per the technical specifications established in this RAC, Appendix 4.
RAC-03.345 Types of aircraft observations The aeronautical meteorological service provider must ensure that it receives the following observations, made on board aircraft:
- a)routine aircraft observations during the en-route and initial climb phases of flight; and b) special aircraft observations and other non-routine aircraft observations during any phase of flight.
RAC-03.350 Routine aircraft observations - designation The aeronautical meteorological service provider, in coordination with the DGAC, must ensure that when air-ground data link is used and automatic dependent surveillance (ADS) or secondary surveillance radar (SSR) Mode S is applied, it receives automated routine observations every 15 minutes during the en-route phase, and every 30 seconds in the initial climb phase in the first 10 minutes of flight.
SUBPART E AIRCRAFT OBSERVATIONS AND REPORTS RAC-03.340 Obligations of States (See CCA RAC-03.340) The Costa Rican State shall arrange, in accordance with the provisions of this Subpart, for observations to be made by aircraft on its registry flying on international air routes, as well as the recording and reporting of such observations.
The aeronautical meteorological service provider must ensure that it receives and retransmits aircraft observations as it corresponds per the technical specifications established in this RAC, Appendix 4.
RAC-03.345 Types of aircraft observations The aeronautical meteorological service provider must ensure that it receives the following observations, made on board aircraft:
- a)routine aircraft observations during the en-route and initial climb phases of flight; and b) special aircraft observations and other non-routine aircraft observations during any phase of flight.
RAC-03.350 Routine aircraft observations - designation The aeronautical meteorological service provider, in coordination with the DGAC, must ensure that when air-ground data link is used and automatic dependent surveillance (ADS) or secondary surveillance radar (SSR) Mode S is applied, it receives automated routine observations every 15 minutes during the en-route phase, and every 30 seconds in the initial climb phase in the first 10 minutes of flight.
SUBPART E AIRCRAFT OBSERVATIONS AND REPORTS RAC-03.340 Obligations of States (See CCA RAC-03.340) RAC-03.355 Routine aircraft observations - exemptions When there are helicopter operations conducted to and from aerodromes located on offshore structures, routine observations must be made from the helicopters at the points and at the times agreed upon by the aeronautical meteorological service provider and the helicopter operators concerned.
RAC-03.360 Frequency of routine aircraft observations In the case of air routes with high-density air traffic (as occurs with organized tracks), one aircraft among those operating at each flight level is designated to make routine observations at intervals of approximately one hour, in accordance with RAC-03.350. The aeronautical meteorological service provider must know the procedures, in coordination with the DGAC, so that if necessary, its weather watch activities can rely on the routine observations of the corresponding regional air navigation agreement.
RAC-03.365 Routine aircraft observations during the initial climb phase For the requirement to report during the initial climb phase, one aircraft is designated, at intervals of approximately one hour, at each aerodrome, to make routine observations in accordance with RAC-03.350. The aeronautical meteorological service provider must know the procedures, in coordination with the DGAC, so that if it deems it necessary, its weather watch activities can rely on the routine observations of the corresponding regional air navigation agreement.
RAC-03.370 Routine aircraft observations - exemptions The aeronautical meteorological service provider must know that aircraft not equipped with air-ground data link are exempt from making routine aircraft observations.
RAC-03.375 Special aircraft observations (See CCA RAC-03.375) The aeronautical meteorological service provider must ensure that it receives the following special observations, made on board aircraft; all aircraft shall make special observations when the following conditions are encountered or observed:
- a)moderate or severe turbulence; or b) moderate or severe icing; or c) severe mountain wave; or d) thunderstorms without hail, that are obscured, embedded, widespread, or in squall lines; or e) thunderstorms with hail, that are obscured, embedded, widespread, or in squall lines; or f) severe duststorms or sandstorms; or g) a volcanic ash cloud; or h) pre-eruption volcanic activity or a volcanic eruption.
In this context, pre-eruption volcanic activity means that such activity is unusual or has increased, which could presage a volcanic eruption.
- i)from 5 November 2020, the runway braking action is not as good as reported.
RAC-03.380 Other non-routine aircraft observations of aeronave When other meteorological conditions not included in RAC-03.375 are encountered, such as wind shear (cizalladura del viento), which the pilot-in-command estimates may affect operational safety or seriously impair the efficiency of other aircraft operations, the pilot-in-command must advise the appropriate air traffic services unit as soon as possible.
Icing, turbulence, and, to a large extent, wind shear (cizalladura del viento) are elements that at present cannot be satisfactorily observed from the ground and for which, in most cases, aircraft observations constitute the only available evidence.
The aeronautical meteorological service provider must ensure, through coordination with the DGAC, that special aircraft observations are received.
RAC-03.385 Notification of aircraft observations during flight (See CCA RAC-03.385) The aeronautical meteorological service provider must ensure, through coordination with the DGAC, that notification of aircraft observations during flight is received.
Aircraft observations must be reported via air-ground data link. In cases where air-ground data link is not available or is not suitable, special observations and other extraordinary aircraft observations during flight shall be reported by voice communications.
RAC-03.390 Notification of aircraft observations The aeronautical meteorological service provider must ensure, through coordination with the DGAC, that notification of aircraft observations is received.
Aircraft observations must be reported during flight, at the time the observation is made or as soon as possible thereafter.
RAC-03.395 Name of aircraft observations The aeronautical meteorological service provider must ensure that notifications of aircraft observations are received as air-reports (aeronotificaciones).
RAC-03.400 Relay of air-reports by air traffic services units The aeronautical meteorological service provider must make arrangements with the competent ATS authorities to ensure that it receives from the air traffic services units:
- a)special air-reports (aeronotificaciones especiales) by voice communications, which the air traffic services units shall relay without delay to the associated meteorological watch office (oficina de vigilancia meteorológica); and b) routine and special air-reports (aeronotificaciones ordinarias y especiales) by data link communications, which the air traffic services units shall relay without delay to the associated meteorological watch office (oficina de vigilancia meteorológica), to the WAFCs, and to the centres designated by regional air navigation agreement for the operation of the aeronautical fixed service and internet-based services.
RAC-03.405 Recording and post-flight reporting of aircraft observations concerning volcanic activity Special aircraft observations concerning pre-eruption volcanic activity, a volcanic eruption, or a volcanic ash cloud must be recorded on the special air-report of volcanic activity form. The aeronautical meteorological service provider must include a copy of said form with the flight documentation supplied to flights operating on routes that, in the opinion of the aeronautical meteorological service provider, could be affected by volcanic ash clouds.
SUBPART F FORECAST RAC-03.410 Use of forecasts (See CCA RAC-03.410) The aeronautical meteorological service provider must indicate to users and ATC units that, due to the variability of meteorological elements in space and time, to the limitations of forecasting techniques, and to the limitations imposed by the definitions of some of the elements, the specified value of any of the elements given in a forecast should be understood by the recipient as the most probable value that said element may have during the forecast period. Similarly, it must indicate in the letters of agreement and documentation provided to users that when the time of occurrence or change of an element is given in a forecast, this time should be understood as the most probable.
RAC-03.415 Automatic cancellation of a forecast The issuance of a new forecast by an aerodrome meteorological office (oficina meteorológica de aeródromo), such as a routine aerodrome forecast, automatically cancels any forecast of the same type previously issued for the same place and for the same period of validity or part thereof.
RAC-03.420 Aerodrome forecasts (See CCA RAC-03.420) Aerodrome forecasts must be prepared, based on a regional air navigation agreement, by the aerodrome meteorological office (oficina meteorológica de aeródromo) designated by the aeronautical meteorological service provider.
RAC-03.425 Issuing the aerodrome forecast Aerodrome forecasts (TAF) must be issued at a specified time, not more than one hour before the beginning of their period of validity, and shall consist of a concise statement of the expected meteorological conditions at an aerodrome for a specified period.
RAC-03.430 Content of TAFs (See CCA RAC-03.430) Aerodrome forecasts and amendments thereto must be issued as TAFs and must include the following information in the order indicated:
- a)identification of the type of forecast; b) location indicator; c) time of issuance of the forecast; d) identification of a missing forecast, when applicable; e) date and period of validity of the forecast; f) identification of a cancelled forecast, when applicable; g) surface wind; h) forecast prevailing visibility; i) weather phenomena; 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 TAFs in accordance with a regional air navigation agreement.
The visibility included in TAFs refers to the forecast prevailing visibility.
RAC-03.435 Study and changes to TAF Forecasts (See CCA RAC-03.435) Aerodrome meteorological offices (oficinas meteorológicas de aeródromo) preparing TAFs must keep the forecasts under continuous study and, when necessary, must issue amendments without delay. The length of forecast messages and the number of changes indicated in the forecast must be kept to a minimum.
RAC-03.440 Cancellation of TAFs TAFs that cannot be kept under continuous review must be cancelled.
RAC-03.445 Validity and issuance interval of TAFs The period of validity of routine TAFs must not be less than 6 hours nor more than 30 hours; the period of validity must be determined by regional air navigation agreement.
Routine TAFs valid for less than 12 hours must be issued every 3 hours, and those valid for 12 to 30 hours every 6 hours.
RAC-03.450 Validity of TAF When issuing TAFs, meteorological offices must ensure that at no time is more than one TAF valid at an aerodrome.
RAC-03.455 Landing forecasts Landing forecasts must be prepared by the aerodrome meteorological office (oficina meteorológica de aeródromo) designated by the aeronautical meteorological service provider as determined by regional air navigation agreement; such forecasts are intended to meet the needs of local users and of aircraft within approximately one hour's flying time from the aerodrome.
Landing forecasts must be prepared in the form of a trend-type forecast (pronóstico de tipo tendencia).
RAC-03.460 Trend forecast The trend forecast consists of a concise statement of the expected significant changes in meteorological conditions at that aerodrome, which must be appended to a local routine report, a local special report, a METAR, or a 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.
RAC-03.465 Take-off forecasts Take-off forecasts must be prepared by the aerodrome meteorological office (oficina meteorológica de aeródromo) designated by the aeronautical meteorological service provider, if required by agreement between the aeronautical meteorological service provider and the operators concerned.
RAC-03.470 Content of the take-off forecast The take-off forecast must refer to a specified period of time and contain information on expected conditions over the runway complex, regarding surface wind direction and speed and any variations thereof, temperature, pressure (QNH), and any other element as locally agreed.
It is prepared on request and a take-off forecast shall be provided to operators and flight crew members within the 3 hours before the estimated time of departure.
RAC-03.475 Review and amendments to take-off forecasts Aerodrome meteorological offices (oficinas meteorológicas de aeródromo) preparing take-off forecasts must review such forecasts continuously and must issue amendments immediately when necessary.
RAC-03.480 Area forecasts for low-level flights When the density of traffic operating below flight level 100 (or up to flight level 150 in mountainous areas, or higher, if necessary) warrants the regular issuance and dissemination of area forecasts for such operations, the aeronautical meteorological service provider must determine, in consultation with users, the frequency of issuance, the form, and the fixed time or period of validity for those forecasts, and the criteria for amending them.
RAC-03.485 Format for AIRMET, GAMET SIGWX information When the density of traffic below flight level 100 warrants issuing AIRMET information in accordance with RAC-03.480, the area forecasts for such flights must be prepared in the format agreed between the aeronautical meteorological service providers or meteorological authorities of the States concerned.
When abbreviated plain language is used, the forecasts must be prepared as GAMET area forecasts, using numerical values and abbreviations approved by ICAO; when cartographic form is used, the forecast must be prepared as a combination of wind and temperature forecasts in altitude and SIGWX phenomena. Area forecasts must be issued to cover the layer between the ground and flight level 100 (or up to flight level 150 in mountainous areas, or higher, if necessary) and must include 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.
RAC-03.490 Interval and validity of the area forecast for low-level flights Area forecasts for low-level flights prepared to support the issuance of AIRMET information must be issued every 6 hours with a period of validity of 6 hours and shall be transmitted to the associated meteorological watch offices (oficinas de vigilancia meteorológicas) and aerodrome meteorological offices (oficinas meteorológicas de aeródromo) no later than one hour before the beginning of the validity period.
SUBPART G SIGMET AND AIRMET INFORMATION, AERODROME WARNINGS AND WIND SHEAR WARNINGS AND ALERTS RAC-03.495 SIGMET information (See CCA RAC-03.595) The aeronautical meteorological service provider must ensure that SIGMET messages are received from the associated Meteorological Watch Office (MWO) and that these are received by all aerodrome meteorological offices (oficinas meteorológicas de aeródromo) in the country, for use in verbal briefings and, if necessary, for inclusion in flight documentation.
SIGMET information must be issued by a meteorological watch office (oficina de vigilancia meteorológica) and shall give a concise description in abbreviated plain language of the actual and/or expected occurrence of specified en-route weather phenomena and other phenomena in the atmosphere that may affect the operational safety of aircraft, and of the evolution of those phenomena in time and space.
SIGMET information shall be cancelled when the phenomena are no longer occurring or are no longer expected to occur in the area.
RAC-03.500 Validity of SIGMET information The period of validity of SIGMET messages shall not exceed 4 hours. In the special case of SIGMET messages for volcanic ash clouds and tropical cyclones, the period of validity shall be extended to 6 hours.
SIGMET messages must be issued not more than 4 hours before the start of the validity period. In the special case of SIGMET messages for volcanic ash and tropical cyclones, such messages must be issued as soon as possible but not more than 12 hours before the start of the validity period. SIGMET messages concerning volcanic ash clouds and tropical cyclones shall be updated at least every 6 hours.
RAC-03.505 Coherence between SIGMET and NOTAM information Close coordination shall be maintained between the meteorological watch office (oficina de vigilancia meteorológica) and the associated area control centre/flight information centre to ensure that the information on volcanic ash included in SIGMET and NOTAM messages is coherent.
SIGMET messages related to volcanic ash clouds and tropical cyclones must be based on advisory information provided by the VAACs and TCACs, respectively, designated under a regional air navigation agreement.
RAC-03.510 AIRMET information (See CCA RAC-03.510) The aeronautical meteorological service provider must ensure receipt of AIRMET information issued by the meteorological watch offices (oficinas de vigilancia meteorológica) in accordance with regional air navigation agreements, taking into account the density of air traffic operating below flight level 100. AIRMET information shall give a concise description in abbreviated plain language of the occurrence or expected occurrence of specified en-route weather phenomena that have not been included in the area forecasts for low-level flights issued in accordance with RAC-03.480 and that may affect the operational safety of such flights, and the evolution of those phenomena in time and space.
RAC-03.515 Cancellation and validity of AIRMET information AIRMET information shall be cancelled when the phenomena cease to occur or are no longer expected to occur in the area. The period of validity of AIRMET messages shall not exceed 4 hours.
RAC-03.520 Aerodrome warnings (See CCA RAC-03.520) The aerodrome meteorological office (oficina meteorológica de aeródromo), designated by the competent meteorological service provider, must issue aerodrome warnings with concise information concerning meteorological conditions that could adversely affect aircraft on the ground, including parked aircraft, and the aerodrome facilities and services.
RAC-03.525 Cancellation of aerodrome warnings and period of validity Aerodrome warnings must be cancelled when such conditions no longer occur or are no longer expected to occur at the aerodrome.
RAC-03.530 Wind shear warning and alerts (See CCA RAC-03.530) The aerodrome meteorological office (oficina meteorológica de aeródromo) designated by the appropriate aeronautical meteorological service provider must prepare wind shear warnings (avisos de cizalladura del viento) for aerodromes where wind shear (cizalladura del viento) is considered a factor, in accordance with local arrangements established with the appropriate ATS unit and the operators concerned.
Wind shear warnings (avisos de cizalladura del viento) shall give concise information on the observed or expected presence of wind shear (cizalladura del viento) that could adversely affect aircraft on the approach path or take-off path, or during circling approach between runway level and a height of 500 m (1 600 ft) above it, or affect aircraft on the runway during the landing roll or take-off run. When local topography has proven to cause significant wind shear (cizalladura del viento) at heights above 500 m (1 600 ft) above runway level, the 500 m (1 600 ft) above runway level shall not be considered a restrictive limit.
RAC-03.535 Cancellation of wind shear warning When aircraft reports indicate that wind shear (cizalladura del viento) no longer exists or, after an agreed period without notifications, wind shear warnings (avisos de cizalladura del viento) for arriving aircraft or departing aircraft must be cancelled. The criteria governing the cancellation of a wind shear warning (aviso de cizalladura del viento) must be established locally for each aerodrome by agreement between the meteorological authorities, the appropriate ATS authorities, and the operators concerned.
RAC-03.540 Detection of wind shear by automatic ground-based equipment At aerodromes where wind shear (cizalladura del viento) is detected by automatic ground-based equipment for remote sensing or detection of wind shear (cizalladura del viento), wind shear alerts generated by these systems must be issued. Such alerts shall give concise, up-to-date information on the observed existence of wind shear (cizalladura del viento) involving a headwind/tailwind change of 7.5 m/s (15 kt) or more that could adversely affect aircraft on the final approach path or initial take-off path and on the runway during the landing roll or take-off run. Wind shear alerts must be updated at least every minute. Such an alert must be cancelled as soon as the headwind/tailwind change falls below 7.5 m/s (15 kt).
SUBPART H AERONAUTICAL CLIMATOLOGICAL INFORMATION RAC-03.545 General provisions (See CCA RAC-03.545) The aeronautical meteorological service provider must obtain aeronautical climatological information at the national level, through the collection, processing, and storage of observation data.
Climatological data relating to the sites of new aerodromes and to new runways at existing aerodromes must be collected from as early a date as possible, prior to the commissioning of such aerodromes or runways, as detailed in CCA RAC-03.545.
RAC-03.550 Format of aeronautical climatological information (See CCA RAC-03.550) The aeronautical climatological information necessary for the planning of aeronautical operations must be prepared in the form of aerodrome climatological tables and aerodrome climatological summaries. This information must be provided to aeronautical users as agreed between the aeronautical meteorological service provider and said users.
RAC-03.555 Base period for climatological information Aeronautical climatological information for aerodromes subject to certification must normally be based on observations made over a period of at least five years, and said period must be indicated in the information provided.
RAC-03.560 Climatological data relating to the siting of new aerodromes or new runways Climatological data relating to the sites of new aerodromes and to new runways at existing aerodromes must be collected from as early a date as possible, prior to the commissioning of such aerodromes or runways.
RAC-03.565 Aerodrome climatological tables The aeronautical meteorological service provider must make the necessary arrangements to collect and retain the required observation data and be able to:
- a)prepare aerodrome climatological tables for each regular and alternate international aerodrome within its territory; and b) make such tables available to the aeronautical user within a period of time agreed between the aeronautical meteorological service provider and said user.
RAC-03.570 Aerodrome climatological summaries Aerodrome climatological summaries must follow the procedures prescribed by the World Meteorological Organization (WMO). When computerized facilities are available for storing, processing, and retrieving information, the summaries must be published or otherwise made available to aeronautical users upon request. When such computerized facilities are not available, the summaries must be prepared using the models specified by the WMO and must be published and kept up to date, as necessary. The climatological summaries for the main aerodromes of the country subject to international certification must be updated by the aeronautical meteorological service provider within the first 3 months of each year.
RAC-03.575 Copies of meteorological observation data The aeronautical meteorological service provider must provide, upon request and to the extent possible, to any other meteorological authority, operators, and others concerned with the application of meteorology to international air navigation the meteorological observation data necessary for purposes of accident investigation or other types of investigations, or for operational analysis.
SUBPART I SERVICE FOR OPERATORS AND FLIGHT CREW MEMBERS RAC-03.580 General provisions (See CCA RAC-03.580) The aeronautical meteorological service provider must provide meteorological information to operators and flight crew members for:
- a)pre-flight planning by operators; b) in-flight re-planning by operators using centralized operational control of flight operations; c) use by flight crew members before departure; and d) aircraft in flight.
RAC-03.585 Characteristics of the information provided to operators and flight crew members The aeronautical meteorological service provider must ensure that the meteorological information provided to operators and flight crew members takes into account the time, altitude, and geographical extent. Consequently, the information must be valid for the fixed time or for an appropriate period and must extend to the aerodrome of intended landing, also covering the meteorological conditions expected between the aerodrome of intended landing and the alternate aerodromes designated by the operator.
RAC-03.590 Meteorological information supplied to operators and flight crew members (See CCA RAC-03.590) The meteorological information provided to operators and flight crew members must be up to date and must include the following information, as established by the aeronautical meteorological service provider in consultation with the operators concerned:
- a)forecasts of 1) wind and temperature in altitude; 2) humidity in altitude; 3) geopotential altitude of flight levels; 4) flight level and temperature of the tropopause; 5) direction, speed, and flight level of maximum wind; and 6) SIGWX phenomena; and 7) cumulonimbus clouds, icing, and turbulence b) METAR or SPECI (including trend forecasts issued in accordance with the regional air navigation agreement) for the departure and intended landing aerodromes, and for the take-off alternate, en-route alternate, and destination alternate aerodromes; c) TAF or amendments thereto for the departure and intended landing aerodromes, and for the take-off alternate, en-route alternate, and destination alternate aerodromes; d) take-off forecasts; e) SIGMET information and appropriate special air-reports (aeronotificaciones especiales) related to the entire route; the appropriate special air-reports (aeronotificaciones especiales) shall be those that have not already been used in the preparation of SIGMET.
- f)advisory information on volcanic ash and tropical cyclones relevant to the entire route; g) as determined by regional air navigation agreement, GAMET area forecast and/or area forecasts for low-level flights prepared in cartographic form to complement the issuance of AIRMET information, as well as AIRMET information for low-level flights related to the entire route; h) aerodrome warnings for the local aerodrome; i) satellite meteorological images; and j) ground-based weather radar information; and k) advisory information on space weather conditions of relevance to the entire route.
RAC-03.595 Digital forecasts provided by WAFCs The forecasts listed in RAC-03.590 a) shall be generated from the digital forecasts provided by the WAFCs, when these forecasts cover the intended flight path with respect to time, altitude, and geographical extent, unless otherwise agreed between the aeronautical meteorological service provider and the operator concerned.
RAC-03.600 Forecasts originated by WAFCs (See CCA RAC-03.600) When forecasts are determined to have been originated by the WAFCs, their meteorological content shall not be modified.
RAC-03.605 Forecasts in cartographic form (See CCA RAC-03.605) When provided in cartographic form, the wind and temperature forecasts in altitude listed in RAC 03.590 a), 1) shall constitute fixed-time prognostic charts for the specified flight levels see CCA RAC-03.605.
RAC 03.610 Wind, temperature, and SIGWX forecasts above flight level 100 Wind and temperature forecasts in altitude and SIGWX phenomena forecasts, above flight level 100, required for pre-flight planning and in-flight re-planning by the operator, must be provided as soon as they are available, but at least 3 hours before departure. All other meteorological information required for pre-flight planning and in-flight re-planning by the operator shall be provided as soon as possible.
RAC 03.615 Coordination with authorities of other States When necessary, the aeronautical meteorological service provider must initiate coordination measures with the meteorological authorities or aeronautical meteorological service providers of other States, in order to obtain from them the required reports or forecasts.
RAC 03.620 Location for the supply of meteorological information The aeronautical meteorological service provider must ensure that the location for the supply of meteorological information is situated so as to be easily accessible for providing verbal briefings, consultations, and flight documentation to flight crew members or other flight operations personnel.
Meteorological information shall be provided to operators and flight crew members at the location determined by the aeronautical meteorological service provider, after consultation with the operators, and at the time agreed between the aerodrome meteorological office (oficina meteorológica de aeródromo) and the operator concerned. The service shall be limited, for pre-flight planning, to flights commencing within the territory of the Costa Rican State. At aerodromes where no aerodrome meteorological office (oficina meteorológica de aeródromo) exists, appropriate arrangements shall be established between the meteorological service provider and the operator concerned to provide the meteorological information.
RAC 03.625 Verbal briefing, consultation, and display of information (See CCA RAC-03.625) Verbal briefing or consultation must be provided, upon request, to flight crew members or other flight operations personnel. Its purpose must be to supply the most recent information available on existing and expected meteorological conditions along the route to be followed, at the aerodrome of intended landing, alternate aerodromes, and other pertinent aerodromes, either to explain and amplify the information contained in the flight documentation or, if so agreed between the meteorological service provider and the operator, in lieu of flight documentation.
The meteorological information used in the verbal briefing, consultation, and display shall include all or some of the data listed in RAC 03.590.
RAC 03.630 Difference between verbal briefing and aerodrome forecast If the aerodrome meteorological office (oficina meteorológica de aeródromo) expresses an opinion on the development of meteorological conditions at an aerodrome that differs appreciably from the aerodrome forecast included in the flight documentation, such discrepancy must be pointed out to the flight crew members. The part of the verbal briefing dealing with the divergence must be recorded at the time of the verbal briefing, and this record must be made available to the operator.
RAC 03.635 Provision of verbal briefing, consultation, display of information, or flight documentation The verbal briefing, consultation, presentation of information, or flight documentation required shall normally be provided by the aerodrome meteorological office associated with the departure aerodrome. At an aerodrome where these services are not available, arrangements to meet the needs of flight crew members shall be determined between the aeronautical meteorological service provider and the operator concerned. In exceptional circumstances, such as an undue delay, the aerodrome meteorological office associated with the aerodrome shall provide or, if this is not feasible, shall arrange for the provision of a new verbal briefing, consultation, or flight documentation, as necessary.
RAC 03.640 Appropriate means for the provision of verbal briefing, consultation, and presentation of information The flight crew member or other flight operations personnel for whom the verbal briefing, consultation, or flight documentation has been requested shall visit the aerodrome meteorological office at the time agreed between the aerodrome meteorological office and the operator concerned. When local conditions at an aerodrome do not allow for facilitating verbal briefings or consultation in person, the aerodrome meteorological office shall provide those services by telephone or by other appropriate telecommunications means.
RAC 03.645 Flight documentation The flight documentation to be made available shall comprise the information listed in RAC 03.590 a) 1), and 6), b), c), e), f) and, if applicable, g). However, when so agreed between the aeronautical meteorological service provider and the operator concerned, the documentation for flights of two hours' duration or less, after a brief intermediate stop or turnaround servicing, shall be limited to the data necessary for operations, but in all cases shall comprise at least the information mentioned in RAC 03.590 b), c), e), f) and, if applicable, g).
RAC 03.650 Differences in flight documentation When it becomes evident that the meteorological information to be included in the flight documentation will differ significantly from that provided for pre-flight planning and in-flight planning, the operator shall be informed immediately thereof and, if possible, shall be provided with the revised information, as agreed between the operator and the relevant aerodrome meteorological office.
RAC 03.655 Amendments or updated information In cases where the need for an amendment arises after providing the flight documentation and before the aircraft takes off, the aerodrome meteorological office, as locally agreed, shall issue the necessary amendment or updated information to the operator or to the local air traffic services unit, for transmission to the aircraft.
RAC 03.660 Retention of information The aeronautical meteorological service provider shall retain, either as computer files or in printed form, for a period of at least 30 days from the date of their issuance, the information provided to flight crew members. This information shall be made available to those requesting it for inquiries or investigations and, for these purposes, shall be retained until the inquiry or investigation has been completed.
RAC 03.665 Automated pre-flight information systems for verbal briefing, consultation, flight planning, and flight documentation Where the aeronautical meteorological service provider uses automated pre-flight information systems to provide and present meteorological information to operators and flight crew members for self-briefing, flight planning, and flight documentation purposes, the information provided and displayed shall conform to the provisions contained in RAC 03.590 to RAC 03.655 inclusive.
RAC 03.670 Common points of access to automated information systems (See CCA RAC-03.670) Automated pre-flight information systems intended to provide operators, flight crew members, and other aeronautical personnel concerned with a harmonized, common point of access to meteorological information and aeronautical information services information shall be established by agreement between the aeronautical meteorological service provider and the relevant civil aviation authority or the agency to which the authority to provide service has been delegated in accordance with RAC-15 Aeronautical Information Services, Executive Decree No. 42396-MOPT, Subpart D, RAC-15.040.
RAC 03.675 Responsibility for the quality control and management of meteorological information (See CCA RAC-03.675) Where automated pre-flight information systems are used so that operators, flight crew members, and other aeronautical personnel concerned have a harmonized, common point of access to meteorological information and aeronautical information services information, the aeronautical meteorological service provider concerned shall remain responsible for the quality control and quality management of the meteorological information provided through such systems in accordance with RAC-03.030.
RAC 03.680 Information for aircraft in flight a) The aerodrome meteorological office or the meteorological watch office shall provide meteorological information for use by aircraft in flight to its associated air traffic services unit and by means of the D-VOLMET service or VOLMET broadcasts, as determined by a regional air navigation agreement. Meteorological information for planning by the operator for aircraft in flight shall be provided, on request, as agreed between the aeronautical meteorological service provider or the meteorological authorities and the operator concerned.
- b)Meteorological information for use by aircraft in flight shall be provided to the air traffic services unit in accordance with the specifications of Subpart J.
- c)Meteorological information shall be provided by means of the D-VOLMET service or VOLMET broadcasts in accordance with the specifications of Subpart K.
SUBPART J INFORMATION FOR AIR TRAFFIC SERVICES AND SEARCH AND RESCUE SERVICES, AND AERONAUTICAL INFORMATION RAC 03.685 Information for air traffic services units (See CCA RAC-03.685) The aeronautical meteorological service provider shall designate the aerodrome meteorological office or the meteorological watch office to be associated with each air traffic services unit.
The associated aerodrome meteorological office or meteorological watch office, in coordination with the air traffic services unit, shall arrange for the provision to that unit of the up-to-date meteorological information necessary for the performance of its functions.
RAC 03.690 Type of office for air traffic services units The aerodrome meteorological office shall be associated with an aerodrome control tower or an approach control unit to provide meteorological information.
RAC 03.695 Meteorological offices associated with approach control units The meteorological watch office shall be associated with a flight information centre or an area control centre to provide meteorological information.
When, due to local circumstances, it is convenient for the functions of an aerodrome meteorological office or an associated meteorological watch office to be shared among two or more aerodrome meteorological offices or meteorological watch offices, the division of responsibility shall be determined by the aeronautical meteorological service provider in consultation with the competent ATS authority.
RAC 03.700 Meteorological information for aircraft emergencies All meteorological information requested by an air traffic services unit in connection with an aircraft emergency shall be provided as soon as possible.
RAC 03.705 Information for search and rescue services units The aerodrome meteorological offices or the meteorological watch offices designated by the aeronautical meteorological service provider in accordance with regional air navigation agreements, shall provide the search and rescue services units with the meteorological information they require, in the form as mutually agreed. To this end, the designated aerodrome meteorological office or meteorological watch office shall maintain liaison with the search and rescue services unit throughout the search and rescue operation.
RAC 03.710 Information for aeronautical information services units The aeronautical meteorological service provider, in coordination with the corresponding civil aviation authority, shall make the necessary arrangements to provide the aeronautical information services units with the up-to-date meteorological data they need for the performance of their functions.
SUBPART K COMMUNICATIONS REQUIREMENTS AND USE RAC 03.715 Communications requirements for air traffic services units (See CCA.RAC-03.715) The aeronautical meteorological service provider shall ensure, in conjunction with the competent authority, the maintenance of suitable telecommunications facilities to enable aerodrome meteorological offices and, where necessary, aeronautical meteorological stations, to provide the required meteorological information to the air traffic services units at the aerodromes for which they are responsible, and in particular to the aerodrome control towers, the approach control units, and the aeronautical telecommunication stations serving those aerodromes.
RAC 03.720 Communications requirements for air traffic services and search and rescue services The aeronautical meteorological service provider shall ensure, in conjunction with the competent authority, the maintenance of suitable telecommunications facilities to enable meteorological watch offices to provide the required meteorological information to the 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 they are responsible, and in particular to the flight information centres, area control centres, and rescue coordination centres, and to the corresponding aeronautical telecommunication stations.
RAC 03.725 Communications requirements for world area forecast centres (See CCA RAC-03.725) The aeronautical meteorological service provider shall ensure, in conjunction with the competent authority, the maintenance of suitable telecommunications facilities to enable the world area forecast centres to provide the necessary information produced by the world area forecast system to the aerodrome meteorological offices, meteorological authorities, and other users.
RAC 03.730 Direct speech channels between meteorological offices and air traffic services units The telecommunications facilities between aerodrome meteorological offices and, as required, between aeronautical meteorological stations and the aerodrome control towers or approach control units, shall permit direct speech communications; the speed with which these communications can be established shall be such that the required points can normally be contacted within approximately 15 seconds ("approximately 15 seconds" refers to telephone communications requiring the intervention of an exchange and "5 minutes" refers to printed communications requiring retransmission).
RAC 03.735 Characteristics of communications between meteorological watch offices and flight information centres, area control centres, and rescue coordination centres The telecommunications facilities between aerodrome meteorological offices or meteorological watch offices and the flight information centres, area control centres, rescue coordination centres, and aeronautical telecommunication stations, shall permit:
- a)direct speech communications; the speed with which these communications can be established shall be such that it is normally possible to contact the required points within approximately 15 seconds; and communications; the transit time of messages shall not exceed 5 minutes ("approximately 15 seconds" refers to telephone communications requiring the intervention of an exchange and "5 minutes" refers to printed communications requiring retransmission).
- b)printed communications when the recipients need a written record of the communications; the transit time of messages should not exceed 5 minutes.
RAC 03.740 Supplementary communications equipment The telecommunications facilities required in accordance with RAC 03.730 and RAC 03.735 shall be supplemented, as necessary, with other types of visual or auditory communications, such as closed-circuit television or other systems independent of information processing.
RAC 03.745 Establishment of suitable telecommunications facilities for obtaining meteorological information from aerodrome meteorological offices. As agreed between the aeronautical meteorological service provider and the operators, arrangements shall be made to allow the latter to establish suitable telecommunications facilities for obtaining meteorological information from the aerodrome meteorological offices or from other appropriate sources.
RAC 03.750 Establishment of suitable telecommunications facilities for obtaining meteorological information from other meteorological offices Suitable telecommunications facilities shall be maintained to allow meteorological offices to exchange meteorological information for operations with other meteorological offices.
RAC 03.755 Operation of the exchange of meteorological information (See CCA RAC-03.755) The telecommunications facilities used in the exchange of meteorological information for operations shall be of the aeronautical fixed service or, in the case of the exchange of meteorological information for operations where time is not critical, of the public Internet, subject to availability, satisfactory performance, and bilateral/multilateral and/or regional air navigation agreements.
RAC 03.760 Use of aeronautical fixed service and public Internet communications - Meteorological bulletins (See CCA RAC-03.760) Meteorological bulletins containing meteorological information for operations to be transmitted via the aeronautical fixed service or the public Internet shall originate from the appropriate meteorological office or aeronautical meteorological station.
RAC 03.765 Use of aeronautical fixed service communications - information produced by the world area forecast system Information produced by the world area forecast system in digital form shall be transmitted using binary data communications techniques. The method and channels applied for the dissemination of this produced information shall be those determined by regional air navigation agreement.
RAC 03.770 Use of aeronautical mobile service communications The content and format of meteorological information transmitted to aircraft and that transmitted by aircraft shall conform to the provisions of this RAC.
RAC 03.775 Use of the aeronautical data link service - content of D-VOLMET (See CCA.RAC-03.775) The D-VOLMET service shall contain current METAR and SPECI, together with trend-type forecasts if available, TAF and SIGMET, special air-reports not covered by a SIGMET and, if available, AIRMET.
RAC 03.780 Use of the aeronautical broadcasting service - content of VOLMET broadcasts Continuous VOLMET broadcasts, normally on very high frequency (VHF), shall contain current METAR and SPECI and trend-type forecasts if available. Scheduled VOLMET broadcasts, normally on high frequency (HF), shall contain current METAR and SPECI, together with trend-type forecasts if available, and, where so determined by a regional air navigation agreement, TAF and SIGMET.
APPENDICES AND ATTACHMENTS APPENDIX 1 FLIGHT DOCUMENTATION — MODEL CHARTS AND FORMS:
MODEL A OPMET Information MODEL IS Upper wind and upper temperature chart for a standard isobaric surface Example 1. Arrows, feathers, and pennants (Mercator projection) Example 2. Arrows, feathers, and pennants (polar stereographic projection) MODEL SWH Significant weather chart (high level) Example 1. Polar stereographic projection (showing jet stream vertical extent) MODEL SWM Significant weather chart (medium level) MODEL SWL Significant weather chart (low level) Example 1 Example 2 MODEL TCG Tropical cyclone advisory information in graphical format MODEL VAG Volcanic ash advisory information in graphical format MODEL STC SIGMET reports for tropical cyclones in graphical format MODEL SVA SIGMET reports for volcanic ash in graphical format MODEL SGE SIGMET reports for phenomena other than tropical cyclones or volcanic ash in graphical format MODEL SN Sheet of notations used in flight documentation APPENDIX 2 TECHNICAL SPECIFICATIONS RELATING TO THE WORLD AREA FORECAST SYSTEM AND METEOROLOGICAL OFFICES 1. WORLD AREA FORECAST SYSTEM 1.1 Formats and codes The world area forecast centres (WAFCs) shall adopt uniform formats and codes for the supply of forecasts.
1.2 Gridded forecasts in altitude 1.2.1 Forecasts of upper wind; upper temperature; humidity; direction, speed, and flight level of maximum wind; flight level and temperature of the tropopause; areas of cumulonimbus clouds, icing, clear-air and in-cloud turbulence; and geopotential altitude of flight levels shall be prepared four times a day at a WAFC and shall be valid for fixed validity times of 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, and 36 hours after the time of observation (0000, 0600, 1200, and 1800 UTC) of the synoptic data on which the forecasts were based. The dissemination of each forecast shall be carried out in the order listed above and shall be completed as soon as technically possible, but no later than 6 hours after the standard time of observation.
1.2.2 The gridded forecasts prepared by a WAFC shall comprise: a) data on winds and temperatures 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 the 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 the 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); g) clear-air turbulence for layers centred at flight levels 240 (400 hPa), 270 (350 hPa), 300 (300 hPa), 340 (250 hPa), 390 (200 hPa), and 450 (150 hPa); h) in-cloud turbulence for layers centred at flight levels 100 (700 hPa), 140 (600 hPa), 180 (500 hPa), 240 (400 hPa), and 300 (300 hPa); and Layers centred at one of the flight levels mentioned in f) and h) have a depth of 100 hPa.
Layers centred at one of the flight levels mentioned in g) have a depth of 50 hPa.
- i)data on geopotential altitude 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).
1.2.3 The preceding gridded forecasts shall be issued by the WAFCs in the form of binary code using the GRIB code form prescribed by the World Meteorological Organization (WMO).
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 preceding gridded forecasts shall be prepared by the WAFCs on a regular grid with a horizontal resolution of 1.25° of latitude and longitude.
1.3 Significant weather (SIGWX) forecasts 1.3.1 General provisions 1.3.1.1 Forecasts of significant weather phenomena en route shall be prepared as SIGWX forecasts four times a day at a WAFC and shall be valid for fixed valid times 24 hours after the time (0000, 0600, 1200, and 1800 UTC) of the synoptic data on which the forecasts were based. The dissemination of each forecast shall be completed as soon as technically possible, but no later than 9 hours after the standard time of observation.
1.3.1.2 SIGWX forecasts shall be issued in binary code form, using the BUFR code form prescribed by WMO.
The BUFR code form is contained in the Manual on Codes (WMO No. 306), Volume I.2, Part B — Binary Codes.
1.3.2 Types of SIGWX forecasts. SIGWX forecasts shall be issued as high-level SIGWX forecasts for flight levels between 250 and 630.
Medium-level SIGWX forecasts for flight levels between 100 and 250 in limited geographical areas shall continue to be issued until such time as the flight documentation to be generated from the gridded forecasts of cumulonimbus clouds, icing, and turbulence fully meets user requirements.
1.3.3 Elements to be included in SIGWX forecasts. SIGWX forecasts comprise the following elements:
- a)tropical cyclones, provided the mean surface wind speed for the 10-minute period 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 sandstorms or dust storms; f) cumulonimbus clouds associated with thunderstorms and with the elements a) to e); In SIGWX forecasts, areas of non-convective clouds with moderate or severe turbulence within the clouds and/or moderate or severe icing shall be included.
- g)flight level of the tropopause; h) jet streams; i) information on the location of volcanic eruptions producing ash clouds of significance to aircraft operations, including: the volcanic eruption symbol at the volcano location 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 shall indicate “CHECK SIGMET, ADVISORIES FOR TC AND VA, AND ASHTAM AND NOTAM FOR VA”; and j) information on the location of a release to the atmosphere of radioactive materials of significance to aircraft operations, including: 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, the latitude/longitude of the location of the release, and (if known) the name of the site of the radioactive source. In addition, the legend of SIGWX charts indicating the release of radiation shall contain “CHECK SIGMET AND NOTAM FOR RADIOACTIVE CLOUD”.
Medium-level SIGWX forecasts include all the elements mentioned, as applicable.
Appendix 5 to this RAC contains the elements to be included in SIGWX forecasts for low-level flights (i.e., below flight level 100).
1.3.4 Criteria for the inclusion of elements in SIGWX forecasts. The following criteria have been applied for SIGWX forecasts:
- a)the elements a) to f) listed in 1.3.3 shall be included only if expected to occur between the lower and upper level of the SIGWX forecast; b) the abbreviation “CB” shall be included only when it refers to the occurrence or expected occurrence of cumulonimbus clouds:
- 1)affecting an area with a maximum spatial coverage of 50% or more of the area concerned; 2) along a line with little or no space between individual clouds; or 3) embedded in cloud layers or obscured by haze; c) the inclusion of “CB” shall mean that all weather phenomena normally associated with cumulonimbus clouds are included, i.e., thunderstorm, moderate or severe icing, moderate or severe turbulence, and hail; d) when a volcanic eruption or the release of radioactive materials to the atmosphere warrants the inclusion of the volcanic eruption symbol or the radioactive materials in the atmosphere symbol in SIGWX forecasts, these shall be included regardless of the height reported for the ash column or radioactive materials or the height forecast to be reached; and e) where there is coincidence or partial overlap of elements a), i), and j) of 1.3.3, the highest priority shall be given to element i), followed by elements j) and a). The element with the highest priority shall be placed at the site of the event, and an arrow shall be used to link the site of the other elements to their associated symbol or text box.
2. AERODROME METEOROLOGICAL OFFICES 2.1 Use of information produced by the world area forecast system (WAFS) 2.1.1 For the preparation of flight documentation, the aerodrome meteorological offices shall use the forecasts issued by the WAFCs, provided these forecasts cover the intended flight path in respect to time, altitude, and geographical extent, unless otherwise agreed between the meteorological authority and the operator concerned.
2.1.2 To ensure uniformity and standardization of flight documentation, the WAFS data in GRIB and BUFR received shall be decoded as standardized WAFS charts in accordance with the relevant provisions of this RAC, and the meteorological content and originator identification of the WAFS forecasts shall not be amended.
2.2 Notification to the WAFC of significant discrepancies Aerodrome meteorological offices using BUFR-encoded WAFS data shall immediately notify the WAFC concerned if significant discrepancies are detected or reported in relation to WAFS SIGWX forecasts concerning:
- a)icing, turbulence, cumulonimbus clouds that are obscured, frequent, embedded, or occurring in squall lines, and sandstorms or dust storms; and b) volcanic eruptions or release of radioactive materials to the atmosphere, of significance to aircraft operations.
The WAFC receiving the message shall acknowledge receipt to the originator, together with a brief comment on the report and the action taken, using the same means of communication employed by the originator.
Guidance on the notification of significant discrepancies is provided in the Manual of Aeronautical Meteorological Methods (Doc. 8896).
3. VOLCANIC ASH ADVISORY CENTRES 3.1 Volcanic ash advisory information 3.1.1 Volcanic ash advisory information shall be issued in abbreviated plain language, using ICAO-approved abbreviations and self-explanatory numerical values, and shall conform to the template shown in Table A2-1. When ICAO-approved abbreviations are not available, English-language plain text shall be used, a practice that shall be kept to a minimum.
Until 4 November 2020, volcanic ash advisory information shall be disseminated in IWXXM GML format, in addition to the dissemination of this information in accordance with 3.1.1.
3.1.2 From 5 November 2020, volcanic ash advisory information must be disseminated in IWXXM GML format, in addition to this information being disseminated in accordance with 3.1.1.
Technical specifications for IWXXM are contained in the Manual on Codes (WMO No. 306), Volume 1.3, Part D - Representations Derived from Data Models. Guidance on the implementation of IWXXM is contained in the Manual on the Digital Exchange of Aeronautical Meteorological Information (ICAO Doc. 10003).
3.1.3 The volcanic ash advisory information mentioned in Table A2-1, when prepared in graphical format, shall conform to the specifications in Appendix 1 of this RAC and must be 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 (ACC)/flight information centres (FIC), meteorological watch office (MWO), and VAAC shall consist of:
- a)significant pre-eruption volcanic activity: date/time (UTC) of the report; name, and, if known, number of the volcano; location (latitude/longitude); and description of the volcanic activity; and b) volcanic eruption: date/time (UTC) of the report and time of eruption (UTC) if different from the report time; 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 the height of the ash column and the extent of any visible volcanic ash cloud during and after the eruption; and c) cessation of volcanic eruption: date/time (UTC) of the report and time of cessation of the eruption (UTC); name and, if known, number of the volcano; and location (latitude/longitude). Pre-eruption volcanic activity in this context means unusual or increasing volcanic activity that could presage a volcanic eruption.
State volcano observatories may use the volcano observatory notice for aviation (VONA) format to send information to their associated ACC/FIC, MWO, and VAAC.
The VONA format is included in the Manual on the International Airways Volcano Watch (IAVW) – Operational Procedures and List of Contact Points (ICAO Doc. 9766), available on the ICAO website.
5. TROPICAL CYCLONE ADVISORY CENTRES 5.1 Tropical cyclone advisory information 5.1.1 Tropical cyclone advisory information must be issued for tropical cyclones when the maximum 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 Tropical cyclone advisory information must be disseminated in abbreviated plain language, using ICAO-approved abbreviations and self-explanatory numerical values, and shall conform to the template shown in Table A2-2.
5.1.3 Until 4 November 2020, tropical cyclone advisory information must be disseminated in IWXXM GML format, in addition to this information being disseminated in accordance with 5.1.2.
From 5 November 2020, tropical cyclone advisory centres must disseminate tropical cyclone advisory information in IWXXM GML format, in addition to disseminating this information in abbreviated plain language in accordance with 5.1.2.
Technical specifications for the IWXXM are contained in the Manual on Codes (WMO No. 306), Volume 1.3, Part D - Representations Derived from Data Models. Guidance on the implementation of the IWXXM is contained in the Manual on the Digital Exchange of Aeronautical Meteorological Information (ICAO Doc. 10003).
5.1.4 The tropical cyclone advisory information shown in Table A2-2, when prepared in graphical format, shall conform to the specifications in Appendix 1 of this RAC and must be issued using the PNG format.
6. SPACE WEATHER CENTRES 6.1 Space weather advisory information 6.1.1 Space weather advisory information must be issued in abbreviated plain language, using ICAO-approved abbreviations and self-explanatory numerical values, and in accordance with the template in Table A2-3. When ICAO-approved abbreviations are not available, English plain language text must be used, but kept to a minimum.
6.1.2 From 7 November 2019 to 4 November 2020, space weather advisory information must be disseminated in IWXXM GML format, in addition to this information being disseminated in abbreviated plain language in accordance with 6.1.1.
From 5 November 2020, space weather advisory information must be disseminated in IWXXM GML format, and this information must also be disseminated in abbreviated plain language in accordance with 6.1.1.
Technical specifications for IWXXM are contained in the Manual on Codes (WMO No. 306), Volume 1.3, Part D - Representations Derived from Data Models. Guidance on the implementation of IWXXM is contained in the Manual on the Digital Exchange of Aeronautical Meteorological Information (ICAO Doc. 10003).
6.1.3 One or more of the following space weather effects must be included in the space weather advisory information, using their respective abbreviations listed below: HF communication (propagation, absorption) HF COM satellite communications (propagation, absorption) SATCOM GNSS-based navigation and surveillance (degradation) GNSS radiation at flight levels (increased exposure) RADIATION 6.1.4 The following intensities must be included in the space weather advisory information, using their respective abbreviations listed below: moderate (MOD) and severe (SEV) Guidance on the use of these intensities is contained in the Manual on Space Weather Information in Support of International Air Navigation (ICAO Doc. 10100).
6.1.5 Updated advisory information must be issued when necessary, but at least every six hours, until the space weather phenomena are no longer detected or expected to have impacts.
Table A2-1. Template for volcanic ash advisory message Key:
M = mandatory inclusion, part of every message; O = optional inclusion; C = conditional inclusion, included when pertinent; = = a double line indicates that the following text should be placed on the next line.
The value ranges and resolutions for the numerical elements included in volcanic ash advisory messages are presented in Appendix 6, Table A6-4 of this RAC.
The inclusion of a "colon" after each element title is mandatory. The numbers 1 to 19 are included for clarity only and do not form part of the advisory message, as indicated in the example.
1. Used only when the message is issued to indicate that a test or exercise is taking place. When the word "TEST" or the abbreviation "EXER" is included, the message may contain information that must not be used for operational purposes and will end immediately after the word "TEST". [Applicable as of 7 November 2019].
2. International Association of Volcanology and Chemistry of the Earth's Interior 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 four selected layers.
5. If the ash is reported (e.g., AIREP) but is not identifiable from satellite data.
Table A2-2. Template for tropical cyclone advisory message Key:
M = mandatory inclusion, part of every message; C = conditional inclusion, included when pertinent; = = a double line indicates that the following text should be placed on the subsequent line.
The value ranges and resolutions for the numerical elements included in tropical cyclone advisory messages are presented in Appendix 6, Table A6-4 of this RAC.
It is mandatory to include a "colon" after each element title.
The numbers 1 to 21 are included for clarity only and do not form part of the advisory message, as indicated in the example.
APPENDIX 3 TECHNICAL SPECIFICATIONS RELATED TO METEOROLOGICAL OBSERVATIONS AND REPORTS 1. GENERAL PROVISIONS RELATED TO METEOROLOGICAL OBSERVATIONS Meteorological instruments used at an aerodrome must be sited so as to provide data representative of the area for which the measurements are required.
Specifications intended to minimize the risks to aircraft due to the placement of equipment and installations in the operations areas are given in RAC-14 Aerodrome Design and Construction, Volume 1, Decree No. 42395-MOPT, Scope No. 194 to La Gaceta No. 182 of 25 July 2020, in Subpart I - Aerodrome Operational Services, Equipment, and Installations.
At aeronautical meteorological stations, meteorological instruments must be exposed, operated, and maintained in conformity with the practices, procedures, and specifications of the World Meteorological Organization (WMO).
Observers at an aerodrome must be located, as far as possible, so as to be able to provide data representative of the area for which the observations are required.
When automatic equipment forms part of an integrated semi-automated observing system, the visual data display available in local air traffic services units must be a subset and correspond in parallel to the visual data display available in the local meteorological services unit. In these visual displays, each meteorological element must 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 must be issued in abbreviated plain language, in accordance with the template in Table A3-1.
2.1.2 METAR and SPECI must be issued in accordance with the template in Table A3-2 and disseminated in the METAR and SPECI code forms prescribed by the WMO.
The METAR and SPECI code forms are given in the Manual on Codes (WMO No. 306), Volume I.1, Part A - Alphanumeric Codes.
Until 4 November 2020, METAR and SPECI must be disseminated in IWXXM GML format, in addition to being disseminated in accordance with 2.1.2.
2.1.3 From 5 November 2020, METAR and SPECI are disseminated in IWXXM GML format, in addition to being disseminated in accordance with 2.1.2.
Until 4 November 2020, METAR and SPECI must be disseminated in IWXXM GML format, in addition to being disseminated in accordance with 2.1.2.
Technical specifications for IWXXM are contained in the Manual on Codes (WMO No. 306), Volume 1.3, Part D - Representations Derived from Data Models. Guidance on the implementation of IWXXM is contained in the Manual on the Digital Exchange of Aeronautical Meteorological Information (ICAO Doc. 10003).
2.2 Use of CAVOK When the following conditions occur simultaneously at the time of observation:
- a)visibility: 10 km or more, and the minimum visibility is not reported; In local routine and special reports, visibility refers to the value or values to be reported in accordance with 4.2.4.2 and 4.2.4.3; in METAR and SPECI, visibility refers to the value or values to be reported in accordance with 4.2.4.4.
Minimum visibility is reported in accordance with 4.2.4.4 a).
- b)no cloud of operational significance; and c) no weather condition significant for aviation, as indicated in 4.4.2.3, 4.4.2.5, and 4.4.2.6; the information on visibility, runway visual range, present weather, and cloud amount, 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)values which most closely approximate the operating minima of operators using the aerodrome; b) values which satisfy other local needs of the air traffic services units and operators; c) an increase in temperature of 2°C or more from the last report, or another threshold value agreed between the meteorological authorities, the competent ATS authorities, and the operators concerned; d) the available supplementary information regarding the occurrence of significant meteorological conditions in the approach and initial climb-out areas, as indicated in Table A3-1; e) when noise abatement procedures are applied in accordance with the PANS-ATM (ICAO 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 given in the last report, the mean speed before or after the change being 7.5 m/s (15 kt) or more; and f) values that constitute criteria for SPECI.
2.3.2 When required in accordance with Subpart D, RAC-03-200 b), SPECI are issued whenever changes occur in accordance with the following criteria:
- a)when the mean surface wind direction has changed by 60° or more from that given in the last report, the mean speed before 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 last report; c) when the variation from the mean surface wind speed (gusts) has changed by 5 m/s (10 kt) or more from that given in the last report, the mean speed before or after the change being 7.5 m/s (15 kt) or more; d) when any of the following weather phenomena begin, cease, or change in intensity:
freezing precipitation moderate or heavy precipitation (including showers) thunderstorms (with precipitation); e) when any of the following phenomena begin or cease:
freezing fog thunderstorms (without precipitation); f) when the amount of cloud 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 When required in accordance with Subpart D, RAC-03-200 b), SPECI must be issued whenever changes occur in accordance with the following criteria:
- a)when the wind changes 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 wind changes that:
- 1)would require a change in the runway(s) in use; and 2) would indicate that the tailwind and crosswind components on the runway have changed through values representing the main operating limits for the aircraft ordinarily 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, when a significant number of flights are operated under the visual flight rules; In local special reports, visibility refers to the value or values reported in accordance with 4.2.4.2 and 4.2.4.3; in SPECI, visibility refers to the value or values to be reported in accordance with 4.2.4.4.
Visibility refers to "prevailing visibility", except when only the minimum 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 deteriorating and passes through one or more of the following values: 50, 175, 300, 550, or 800 m; d) when any of the following weather phenomena begin, cease, or change in intensity:
. duststorm . sandstorm . funnel clouds (tornado or waterspout); e) when any of the following phenomena begin or cease:
low drifting dust, sand, or snow blowing dust, sand, or snow squall f) when the height of the 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 the 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 a significant number of flights are conducted under 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 agreed between the meteorological authorities and the operators concerned.
The other criteria based on local aerodrome operating minima shall be considered in parallel with similar criteria developed in response to Appendix 5 of this RAC, point 1.3.2 j) for the inclusion of change groups and for the amendment of TAF.
2.3.4 When the deterioration of one meteorological element is accompanied by the improvement of another element, a single SPECI must be issued; this shall then be considered a deterioration report.
3. DISSEMINATION OF METEOROLOGICAL REPORTS 3.1 METAR and SPECI 3.1.1 METAR and SPECI are disseminated to the international OPMET databanks and to the centres designated by regional air navigation agreement for the operation of the aeronautical fixed service satellite distribution system and internet-based services, in accordance with a regional air navigation agreement.
3.1.2 METAR and SPECI are disseminated to other aerodromes in accordance with the regional air navigation agreement.
3.1.3 A SPECI relating to a deterioration of conditions is disseminated immediately after the observation. A SPECI relating to a deterioration of one meteorological element and an improvement of another element is disseminated immediately after the observation.
3.1.4 A SPECI relating to an improvement of conditions must be disseminated only if the improvement has persisted for 10 minutes; if necessary, it must be amended before dissemination 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 the local air traffic services units and made available to the operators and other users at the aerodrome.
3.2.2 Local special reports shall be transmitted to the local air traffic services units as soon as the specified conditions occur. However, as agreed between the meteorological authority and the competent ATS authority concerned, there is no need to issue them with respect to:
- a)any element for which there is, in the local air traffic services unit, a visual display corresponding to the one at the meteorological station, and when arrangements are in force to use that visual display to update the information in local routine and special reports; and b) runway visual range, when an aerodrome observer reports to the local air traffic services all changes corresponding to one or more increments of the reporting scale in use.
Local special reports shall also be made available to operators and other users at the aerodrome.
4. OBSERVING AND REPORTING METEOROLOGICAL ELEMENTS Certain criteria applicable to the meteorological information mentioned in relation to 4.1 to 4.8 for inclusion in aerodrome reports are presented in tabular form in Attachment C.
4.1 Surface wind 4.1.1 Siting 4.1.1.1 Surface wind observations must be made at a height of 10 ± 1 m (30 ± 3 ft) above the ground.
4.1.1.2 Representative observations of surface wind must be obtained by means of sensors appropriately sited. Sensors for surface wind observations obtained in connection with local routine and special reports must be sited so as to provide the best possible indication of conditions along the runway and in the touchdown zone. At aerodromes where the topography or prevailing meteorological conditions are such that significant differences in surface wind occur in different sections of the runway, additional sensors must be installed.
Since, in practice, the surface wind cannot be measured directly on the runway, it is expected that surface wind observations for take-off and landing will be the most practical indication of the winds an aircraft will encounter during take-off and landing.
4.1.2 Displays 4.1.2.1 Visual displays of surface wind relating to each sensor must be located in the meteorological station, with corresponding visual displays in the appropriate air traffic services units. The visual displays in the meteorological station and in the air traffic services units shall refer to the same sensors, and where separate sensors are required, as indicated in 4.1.1.2, the visual displays shall be clearly marked to identify the runway and section of the runway monitored by each sensor.
4.1.2.2 The average values and the significant variations of the surface wind direction and speed measured by each sensor must be obtained and visually displayed by automatic equipment.
4.1.3 Averaging 4.1.3.1 The period for determining the mean values for wind observations must be:
- a)two minutes for local routine and special reports and for wind displays in air traffic services units; and b) ten 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 that discontinuity shall be used to obtain the mean values; hence, the time interval shall be reduced accordingly.
A marked discontinuity occurs when there is an abrupt and sustained change in wind direction of 30° or more, with a 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 period for averaging the measured variations from the mean wind speed (gusts) reported in accordance with 4.1.5.2 c) must be 3 seconds for local routine reports, local special reports, METAR, SPECI, and for wind displays used to indicate variations from the mean wind speed (gusts) in air traffic services units.
4.1.4 Measurement accuracy The reported direction and speed of the mean surface wind, as well as the variations from the mean surface wind, must meet the operationally satisfactory accuracy 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° true and 1 m/s (or 1 kt), respectively. Any observed value that does not fit the reporting scale in use shall be rounded to the nearest step of the scale.
4.1.5.2 In local routine reports, local special reports, METAR, and SPECI:
- a)the units of measurement for 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, these directional variations shall be reported as the two extreme directions between which the surface wind has varied; 2) when the total variation is 60° or more and less than 180° and the wind speed is less than 1.5 m/s (3 kt), the wind direction shall be reported as variable with no mean wind direction; or 3) when the total variation is 180° or more, the wind direction shall be reported as variable with no mean wind direction; c) variations from the mean wind speed (gusts) during the past 10 minutes shall be reported when the maximum wind speed exceeds the mean speed by:
- 1)2.5 m/s (5 kt) or more in local routine and special reports when noise abatement procedures are applied in accordance with the PANS-ATM (Doc. 4444); or 2) 5 m/s (10 kt) or more otherwise; d) when a wind speed of less than 0.5 m/s (1 kt) is reported, it shall be indicated as calm; e) when a wind speed of 50 m/s (100 kt) or more is reported, it shall be indicated as more than 49 m/s (99 kt); and f) if there is a marked discontinuity in the wind direction or speed during the 10-minute period, only the variations from the mean wind direction and mean wind speed occurring after the discontinuity shall be reported.
(A marked discontinuity occurs when there is an abrupt and sustained change in wind direction of 30° or more, with a 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).
4.1.5.3 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 more than one runway is in use and surface wind relating to these runways is observed, the available wind values for each runway shall be indicated, and the runways to which these 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 wind speed values 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 wind speed value shall be reported.
4.2 Visibility 4.2.1 Siting 4.2.1.1 When instrumented systems are used for the measurement of visibility, it must 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 observations of visibility must be obtained by the use of sensors appropriately sited. Sensors for visibility observations for local routine and special reports must be sited to provide the most practical indications of visibility along the runway and in the touchdown zone.
4.2.2 Displays When instrument systems are used for measuring visibility, the visual displays of visibility related to each sensor must be located in the meteorological station with the corresponding visual displays in the appropriate air traffic services units.
The visual displays in the meteorological station and in the air traffic services units must be related to the same sensors and when separate sensors are required as specified in 4.2.1, the visual displays must be clearly marked to identify the area, e.g., runway and section of the runway, monitored by each sensor.
4.2.3 Averaging When instrument systems are used for measuring visibility, the results must be updated every 60 seconds so that representative and current values can be provided. The averaging period shall be:
- a)One minute for routine and special local reports and for visual displays of visibility 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 visibility, only those values occurring after the discontinuity shall be used to obtain the average values.
A marked discontinuity occurs when there is an abrupt and sustained change in visibility lasting at least two minutes, which reaches or exceeds the values corresponding to the criteria for issuing SPECI reports indicated in 2.3.
4.2.4 Reporting 4.2.4.1 In routine local reports, special local reports, METAR and SPECI, when visibility is less than 800 m it is reported in increments of 50 m; when it is 800 m or more but less than 5 km, in increments of 100 m; when it is 5 km or more but less than 10 km, in increments of one kilometre; and when it is 10 km or more, it shall be indicated as 10 km, except when conditions for the use of CAVOK apply.
Any observed value that does not fit the reporting scale used shall be rounded down to the next lower increment of the scale.
In 2.2 the specifications concerning the use of CAVOK are presented.
4.2.4.2 In routine and special local reports, visibility is reported for the full runway or runways together with the units of measurement used to indicate visibility.
4.2.4.3 In routine and special local reports, when instrument systems are used for measuring visibility:
- a)if visibility is observed from more than one location along the runway, as specified in RAC-03.245 Subpart D of this regulation, the representative values for the touchdown zone shall be reported first, followed, as necessary, by the representative values for the midpoint and the stop end of the runway, and the locations for which these values are representative shall be indicated; and b) when there is more than one runway in use and the visibility related to these runways is observed, the available visibility values for each runway shall be reported, and the runways to which these values correspond shall be indicated.
4.2.4.4 In METAR and SPECI, visibility shall be reported as prevailing visibility, as defined in this regulation, Subpart A in Definitions. When visibility is not the same in different directions and:
- a)when the minimum visibility is different from the prevailing visibility, and 1) is less than 1 500 m or 2) is less than 50% of the prevailing visibility and less than 5 000 m; the minimum visibility observed and its general direction relative to the aerodrome reference point shall also be reported, if possible, indicated by reference to one of the eight points of the compass. If the minimum visibility is observed in more than one direction, the most operationally significant direction shall be reported; and b) when visibility fluctuates rapidly and the prevailing visibility cannot be determined, only the lowest visibility shall be reported, without indicating the direction.
4.3 Runway visual range 4.3.1 Siting 4.3.1.1 Runway visual range shall be assessed at a height of approximately 2.5 m (7.5 ft) above the runway for instrument systems or at a height of approximately 5 m (15 ft) above the runway by a human observer.
4.3.1.2 Runway visual range shall be assessed at a lateral distance from the runway centre line not exceeding 120 m. For the observation site to be representative of the touchdown zone, it shall be located approximately 300 m from the threshold, measured longitudinally along the runway; to be representative of the midpoint and the stop end of the runway, it shall be located at a distance of 1 000 to 1 500 m from the threshold and at a distance of approximately 300 m from the other end of the runway. The exact location of these sites and, if necessary, of others, shall be decided after taking into account aeronautical, meteorological and climatological factors, such as long runways, swampy areas and fog-prone areas.
4.3.2 Instrument systems Since accuracy may vary from one instrument design to another, performance characteristics shall be verified before selecting instruments to assess runway visual range. The calibration of forward-scatter meters shall be traceable and verifiable against transmissometer standards, the accuracy of which shall be verified over the intended operating range. Guidance on the use of transmissometers and forward-scatter meters in instrumented runway visual range systems is provided in the Manual of Runway Visual Range Observing and Reporting Practices (Doc. 9328).
4.3.2.1 Instrument 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 Instrument systems based on transmissometers or forward-scatter meters shall be used to assess runway visual range on runways intended for Category I instrument approach and landing operations.
4.3.3 Visual displays 4.3.3.1 When runway visual range is determined by instrument systems, one or more visual displays, as necessary, shall be installed in the meteorological station, with corresponding visual displays in the appropriate air traffic services units. The visual displays in the meteorological station and in the air traffic services units shall be related to the same sensors, and when separate sensors are required, the section of the runway monitored by each sensor shall be clearly identified.
4.3.3.2 When runway visual range is determined by human observers, it shall be reported to the appropriate local air traffic services units whenever there is a change in the value that is to be reported in accordance with the reporting scale [except when the provisions of 3.2.2 a) or b) apply]. The transmission of such reports shall normally be completed within 15 seconds after the end of the observation.
4.3.4 Averaging When instrument systems are used to assess runway visual range, the output data shall be updated at least every 60 seconds so that current and representative values can be provided. The averaging period for runway visual range values shall be:
- a)One minute for routine and special local reports and for visual displays of runway visual range 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, in which case only those values occurring after the discontinuity shall be used to obtain the average values.
A marked discontinuity occurs when there is a sudden and sustained change in runway visual range, lasting at least 2 minutes, which reaches or passes through the values of 800, 550, 300 and 175 m.
4.3.5 Runway light intensity When instrument systems are used to assess runway visual range, separate calculations shall be made for each available runway. For routine and special local reports, the following light intensity shall be used in the calculation:
- a)for a runway with lights on and a light intensity of more than 3% of the maximum available light intensity: the light intensity actually used on that runway; b) for a runway with lights on and a light intensity of 3% or less of the maximum available light intensity: the optimal light intensity most suitable for operational use in the prevailing conditions; and c) for a runway with lights off (or at minimum intensity, pending resumption of operations): the light intensity most suitable for operational use in the prevailing conditions.
In METAR and SPECI, runway visual range shall be based on the same settings of maximum light intensity available on the runway.
Guidance on converting instrument readings into runway visual range values is provided in Attachment D.
4.3.6 Reporting 4.3.6.1 In routine local reports, special local reports, METAR and SPECI, runway visual range shall be reported in increments of 25 m when it is less than 400 m; in increments of 50 m when it is between 400 m and 800 m; and in increments of 100 m when it is more than 800 m. Any observed value that does not fit the reporting scale in use shall be rounded down to the next lower step on the scale.
4.3.6.2 The value of 50 m shall be considered the lower limit and the value of 2 000 m the upper limit for runway visual range. Outside these limits, routine local reports, special local reports, METAR and SPECI shall merely indicate that the runway visual range is less than 50 m or more than 2 000 m.
4.3.6.3 In routine local reports, special local reports, METAR and SPECI: a) when the runway visual range is greater than the maximum value that can be determined by the system in use, it shall be reported using the abbreviation "ABV" in routine and special local 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 less than the minimum value that can be determined by the system in use, it shall be reported using the abbreviation "BLW" in routine and special local 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 routine and special local 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 runway visual range is observed from more than one location along the runway, the representative value for the touchdown zone shall be reported first, followed by the representative values for the midpoint and the 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 these values refer shall be indicated.
4.3.6.5 In METAR and SPECI:
- a)only the representative value for the touchdown zone shall be reported and no indication of location on the runway shall be included; and b) when more than one runway is available for landing, all runway visual range values corresponding to the touchdown zone of those runways shall be indicated, up to a maximum of four runways, and the runways to which these values refer shall be specified.
4.3.6.6 When instrument systems are used for assessing runway visual range, variations in runway visual range during the 10-minute period immediately preceding the observation shall be included in METAR and SPECI if the runway visual range values during the 10-minute period have shown a distinct trend such that the average during the first five minutes varies by 100 m or more from the average during the last five minutes of the period. When the variation in runway visual range values indicates an upward or downward trend, this shall be indicated by the abbreviation "U" or "D" respectively. In cases where actual fluctuations during a 10-minute period show no marked trend, this shall be indicated by the abbreviation "N".
When trend indications are not available, none of the preceding abbreviations shall be included.
4.4 Present weather 4.4.1 Siting When instrument systems are used for observing present weather phenomena indicated in relation to 4.4.2.3 and 4.4.2.4, representative information shall be obtained through the use of suitably sited sensors.
4.4.2 Reporting 4.4.2.1 In routine and special local reports, observed present weather phenomena shall be reported by describing their type and characteristics and qualifying them as to their intensity, as appropriate.
4.4.2.2 In METAR and SPECI, observed present weather phenomena shall be reported by describing their type and characteristics and qualifying them as to their intensity or proximity to the aerodrome, as appropriate.
4.4.2.3 In routine local reports, special local reports, METAR and SPECI, the following types of present weather phenomena shall 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 if the diameter of the largest stones is 5 mm or greater. Small hail or snow pellets GS – Reported if the diameter of the largest stones is less than 5 mm.
- b)Obscurations (hydrometeors) Fog FG Reported if visibility is less than 1 000 m, except when qualified as "MI", "BC", "PR" or "VC" (see 4.4.2.6 and 4.4.2.8). Mist BR Reported if visibility is at least 1 000 m but not more than 5 000 m.
- c)Obscurations (lithometeors) – The following descriptions shall be used only if the obscuration is predominantly due to lithometeors and if visibility is 5 000 m or less, except in the case of "SA" with the qualifier "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(s) (tornado or waterspout) FC Dust storm DS Sand storm SS 4.4.2.4 In routine local reports, special local reports, METAR and SPECI from automatic systems, in addition to the types of precipitation listed in 4.4.2.3 a), the abbreviation UP shall be used for unidentified precipitation when the type of precipitation cannot be determined by the automatic observing system.
4.4.2.5 In routine local reports, special local reports, METAR and SPECI, the following characteristics of present weather phenomena, as appropriate, 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 in Tables A3-1 and A3-2. If 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 qualifiers.
Freezing FZ – Supercooled water droplets or precipitation freezing, used with the types of present weather phenomena in accordance with the templates in Tables A3-1 and A3-2.
At aerodromes with human observers, lightning detection equipment may be used as a supplement to human observations. For aerodromes with automatic observing systems, guidance on the use of lightning detection equipment for reporting thunderstorms is provided in the Manual on Automatic Meteorological Observing Systems at Aerodromes (ICAO Doc. 9837).
4.4.2.6 In routine local reports, special local reports, METAR and SPECI, the following characteristics of present weather phenomena, as appropriate, shall be reported using their respective abbreviations and relevant criteria, as appropriate:
Shower SH – Used to report showers in accordance with the templates in Tables A3-1 and A3-2. Showers observed in the vicinity of the aerodrome (see 4.4.2.8) shall be reported as "VCSH" without qualification regarding type or intensity of precipitation. Blowing BL – Used in accordance with the templates 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 ground level. Low drifting DR – Used in accordance with the templates 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 (fog) MI – Less than 2 m (6 ft) above ground level. Patches BC – Patches of fog scattered over the aerodrome. Partial PR – A substantial part of the aerodrome covered by fog while the remainder is clear.
4.4.2.7 In routine local reports, special local reports, METAR and SPECI from automatic systems, when the showers (SH) mentioned in 4.4.2.6 cannot be determined by a method that takes into account the presence of convective clouds, the precipitation shall not be characterized by SH.
4.4.2.8 In routine local reports, special local reports, METAR and SPECI, the relevant intensity or, as appropriate, the proximity to the aerodrome of the reported present weather phenomena shall be indicated as follows:
(Routine and special local reports) (METAR and SPECI) Light FBL – Moderate MOD (no indication) Heavy HVY + Used with types of present weather phenomena in accordance with the templates in Tables A3-1 and A3-2. Intensity shall be indicated only for precipitation.
Proximity VC – Between approximately 8 and 16 km from the aerodrome reference point and used only in METAR and SPECI with present weather, in accordance with the template in Table A3-2, when not reported in accordance with 4.4.2.5 and 4.4.2.6.
4.4.2.9 In routine local reports, special local 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, as appropriate, of the characteristics given in 4.4.2.5 and 4.4.2.6 and of the intensity or proximity to the aerodrome given in 4.4.2.8, in order to provide a complete description of the present weather of significance for 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) when two different types of weather are observed, they shall be reported as two separate groups, in which the intensity or proximity indicator refers to the weather phenomenon following the indicator. However, different types of precipitation occurring at the time of observation shall be reported as a single group, with the predominant type of precipitation reported first and preceded by only one intensity qualifier referring to the total precipitation.
4.4.2.10 In routine local reports, special local reports, METAR and SPECI from automatic systems, when present weather cannot be observed by the automatic observing system, the present weather shall be replaced by "//" due to a temporary system/sensor failure.
4.5 Clouds 4.5.1 Siting When instrument systems are used for measuring cloud amount and cloud base height, representative observations shall be made through the use of suitably sited sensors. For routine and special local reports, at aerodromes with precision approach runways, sensors for observing cloud amount and cloud base height shall be sited to provide the most practical indications of the cloud amount and cloud base height at the threshold of the runway in use. For this purpose, a sensor shall be installed at a distance of less than 1 200 m (4 000 ft) before the landing threshold.
4.5.2 Visual display When automated equipment is used to measure cloud base height, the visual display of cloud base height shall be located in the meteorological station, with corresponding visual display(s) in the relevant air traffic services units.
The visual displays located in the meteorological station and in the air traffic services units shall refer to the same sensor, and when separate sensors are required, as stipulated in 4.5.1, the area monitored by each sensor shall be clearly identified on the visual displays.
4.5.3 Reference level Cloud base height shall be reported with reference to the aerodrome elevation. When a precision approach runway is in use whose threshold is 15 m (50 ft) or more below the aerodrome elevation, local arrangements shall be made for the cloud base height to be reported to arriving aircraft by reference to the threshold elevation. In the case of reports from offshore structures, the cloud base height shall be reported relative to mean sea level.
4.5.4 Reporting 4.5.4.1 In routine local reports, special local reports, METAR and SPECI, cloud base height shall be reported in increments 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 approaches and landings, as agreed between the meteorological authority and the appropriate ATS authority, the cloud base height, in routine and special local reports, shall 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 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 routine local reports, special local reports, METAR and SPECI:
- a)cloud amount shall 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 shall be indicated as "CB" and "TCU", respectively; c) vertical visibility shall be reported in increments of 30 m (100 ft) up to 600 m (2 000 ft); d) if there are no clouds of operational significance and no restriction on vertical visibility and the abbreviation "CAVOK" is not appropriate, the abbreviation "NSC" shall be used; e) when several layers or masses of clouds of operational significance are observed, their amount and cloud base height shall be reported in ascending order of cloud base height, and in accordance with the following criteria:
- 1)the lowest layer or mass irrespective of amount, shall be reported as FEW, SCT, BKN or OVC, as appropriate; 2) the next layer or mass covering more than 2/8 shall be reported as SCT, BKN or OVC, as appropriate; 3) the next higher layer or mass covering more than 4/8 shall be reported as BKN or OVC, as appropriate; and 4) cumulonimbus or towering cumulus clouds, whenever observed and not reported in 1) to 3); f) when the cloud base is diffuse or ragged, or fluctuates rapidly, the minimum cloud base height or cloud fragments shall be reported; and g) when a particular cloud layer (mass) is composed of cumulonimbus and towering cumulus with a common cloud base, the cloud type shall be reported as cumulonimbus only.
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) that does not correspond to the reporting scale used shall be rounded down to the next lower step of the scale.
4.5.4.5 In routine and special local reports:
- a)the units of measurement used for cloud base height and vertical visibility shall be indicated; and b) when more than one runway is in use and instrument-observed cloud base heights are relevant to those runways, the available cloud base heights for each runway shall be reported, and the runways to which the values correspond shall be indicated.
4.5.4.6 In routine local reports, special local reports, METAR and SPECI from automatic systems:
- a)when the cloud type cannot be observed by the automatic observing system, it shall be replaced in each cloud group by "///"; b) when no clouds are detected by the automatic observing system, this shall be indicated using the abbreviation "NCD"; c) when cumulonimbus clouds or towering cumulus clouds are detected by the automatic observing system and the cloud amount and height of their base cannot be observed, the cloud amount and/or the height of their base shall be replaced by "///"; and d) when the sky is obscured and the vertical visibility value cannot be determined by the automatic observing system, the vertical visibility shall be replaced by "///" due to a temporary system/sensor failure.
4.6 Air temperature and dew-point temperature 4.6.1 Visual display When automated equipment is used to measure air temperature and dew-point temperature, the visual displays of air temperature and dew-point temperature shall be located in the meteorological station with corresponding visual display(s) in the appropriate air traffic services units. The visual displays located in the meteorological station and in the air traffic services units shall refer to the same sensors.
4.6.2 Reporting 4.6.2.1 In routine local reports, special local reports, METAR and SPECI, air temperature and dew-point temperature shall be reported in whole degrees Celsius in stepwise fashion. Any observed value that does not fit the reporting scale in use shall be rounded to the nearest whole degree Celsius, and if the observed value is exactly 0.5°, it shall be rounded up to the next whole degree Celsius.
4.6.2.2 In routine local reports, special local reports, METAR and SPECI, temperatures below 0°C shall be identified.
4.7 Atmospheric pressure 4.7.1 Visual display When automatic equipment is used for measuring atmospheric pressure, QNH and, if required in accordance with 4.7.3.2 b), QFE visual displays related to the barometer shall be located in the meteorological station with corresponding visual 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 visual displays shall be clearly marked to identify the runway to which the QFE value on the visual display refers.
4.7.2 Reference level The reference level for calculating QFE shall be the aerodrome elevation. For non-precision approach runways where the threshold is 2 m (7 ft) or more below or above the aerodrome elevation, and for precision approach runways, QFE, if required, shall refer to the relevant threshold elevation.
4.7.3 Reporting 4.7.3.1 For routine local reports, special local reports, METAR and SPECI, the QNH and QFE shall be calculated in tenths of hectopascals and reported in graduated steps in whole hectopascals, using four digits. Any observed value that does not fit the reporting scale in use shall be rounded down to the next lower whole hectopascal.
4.7.3.2 In routine and special local reports:
- a)the QNH shall be included; b) the QFE shall be included if required by users, as agreed upon between the meteorological authority and the 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, these values shall be reported for each runway and the runways to which the values correspond 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 routine local reports, special local reports, METAR and SPECI, the following recent meteorological phenomena, that is, meteorological phenomena observed at the aerodrome during the period since the last issued report or the last hour, whichever is the shorter period, but which are not perceptible at the time of observation, shall be reported, up to a maximum of three groups, in accordance with the templates in Tables A3-1 and A3-2, in the supplementary information:
- freezing precipitation - moderate or heavy precipitation (including showers) - blowing snow - duststorm, sandstorm - thunderstorm - funnel clouds (tornado or waterspout) - volcanic ash The meteorological authority, in consultation with users, may agree on not providing recent meteorological information where SPECI are issued.
4.8.1.2 The following significant meteorological conditions, or combinations thereof, shall be reported in the supplementary information in routine and special local reports:
- cumulonimbus clouds CB - thunderstorms 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 - duststorm, sandstorm DS, SS - blowing snow BLSN - funnel clouds (tornado or waterspout) FC The location of the condition shall be indicated. Additional information shall be included in plain abbreviated language, if necessary.
4.8.1.3 In automatic routine local reports, special local reports, METAR and SPECI, in addition to the meteorological phenomena listed in 4.8.1.1, recent unknown precipitation shall be reported in accordance with the template in Table A3-2 when the automatic observing system cannot identify it.
The meteorological authority, in consultation with users, may agree on not providing recent meteorological information where SPECI are issued.
4.8.1.4 In METAR and SPECI, when local circumstances so warrant, information concerning wind shear shall be added.
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 could be associated with low-level temperature inversions or local topographical conditions.
4.8.1.5 Until 4 November 2020, in METAR and SPECI, the following shall be included as supplementary information, in accordance with a regional air navigation agreement:
- a)information on sea-surface temperature and on the state of the sea or the significant wave height, provided from aeronautical meteorological stations established on offshore structures in support of helicopter operations; and b) information on the state of the runway, provided by the competent aerodrome authority.
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.
The state of the runway is specified in the Manual on Codes (WMO No. 306), Volume I.1, Part A - Alphanumeric Codes, Code Tables 0366, 0519, 0919 and 1079.
4.8.1.6 From 5 November 2020, in METAR and SPECI, information on sea-surface temperature and on the state of the sea or the significant wave height, provided from aeronautical meteorological stations established on offshore structures in support of helicopter operations, shall be included in the supplementary information, in accordance with a regional air navigation agreement.
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.
APPENDIX 4 TECHNICAL SPECIFICATIONS RELATED TO AIRCRAFT OBSERVATIONS AND REPORTS 1. CONTENT OF AIRCRAFT REPORTS 1.1 Routine aircraft reports by air-ground data link 1.1.1 When air-ground data link is used and automatic dependent surveillance - contract (ADS-C) or Mode S SSR is applied, the elements included in routine aircraft 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 known) Humidity (if known) When ADS-C or Mode S SSR is applied, the requirements for routine aircraft reports may be satisfied by the combination of the ADS-C basic data block/Mode S SSR (data block 1) and the meteorological information data block (data block 2), which are contained in ADS-C or Mode S SSR reports. The ADS-C message format is specified in the PANS-ATM (Doc. 4444), 4.11.4 and Chapter 13, and the Mode S SSR message format in Annex 10, Volume III, Part I - Chapter 5.
1.1.2 When air-ground data link is used while ADS-C is not applied and the Mode S SSR message format is not applied, the elements included in routine reports shall be:
Message type designator Section 1 (Position information) Aircraft identification Position or latitude and longitude Time Flight level or altitude Next position and time over Next significant point
Section 3 (Meteorological information) Air temperature Wind direction Wind speed Turbulence Aircraft icing Humidity (if known) When air-ground data link is used while ADS-C is not applied and the Mode S SSR message format is not applied, the requirements for routine aircraft reports may be satisfied by means of the controller-pilot data link communications (CPDLC) application entitled "Position Report". The details of this data link application are contained in the Manual of Air Traffic Services Data Link Applications (Doc 9694) and in Annex 10, Volume III, Part I.
1.2 Special aircraft reports by air-ground data link When air-ground data link is used, the elements included in special aircraft 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 known) Humidity (if known) Data block 3 The condition prompting the issuance of a special aircraft report (only one condition shall be selected from the list presented in Table A4-1).
The requirements for special aircraft reports may be satisfied by the data link flight information service (D-FIS) application entitled "Special Aircraft Report Service". Details of this data link application are contained in Doc. 9694.
When it concerns the transmission of a special aircraft report of pre-eruption volcanic activity, volcanic eruption or volcanic ash cloud, additional requirements are given in 4.2.
1.3 Special aircraft reports by voice communications When voice communications are used, the elements contained in special aircraft 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) The condition prompting the issuance of a special aircraft report is selected from the list presented in Table A4-1 of this regulation.
Aircraft reports are considered routine, unless otherwise indicated. The message type designators for special aircraft reports are specified in Appendix 1 of the PANS-ATM (ICAO Doc 4444).
In the case of a special aircraft report of pre-eruption volcanic activity, volcanic eruption or volcanic ash cloud, additional requirements are given in 4.2.
2. REPORTING CRITERIA 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 aircraft reports shall be reported in accordance with the following criteria.
2.2 Wind direction Wind direction shall be reported in degrees true, rounded to the nearest whole degree.
2.3 Wind speed 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 wind speed shall be indicated.
2.4 Wind quality flag The wind quality flag shall be reported as 0 when the roll angle is less than 5 degrees and as 1 when the roll angle is 5 degrees or more.
2.5 Air temperature Air temperature shall be reported to the nearest tenth of a degree Celsius.
2.6 Turbulence Turbulence shall be reported in terms of the cube root of the eddy dissipation rate (EDR).
2.6.1 Routine aircraft reports Turbulence shall be reported during the en-route phase of the flight and shall be presented with reference to the 15-minute period immediately preceding the observation. Both the average value and the maximum value of turbulence shall be observed, together with the time of occurrence of the maximum value to the nearest minute. The average and maximum values shall be reported in terms of the EDR cube root. The time of occurrence of the maximum value shall be reported as indicated in Table A4-2. Turbulence shall be reported during the initial climb phase for the first 10 minutes of the flight and shall refer to the 30-second period immediately preceding the observation. The maximum value of turbulence shall be observed.
2.6.2 Interpretation of the turbulence report Turbulence shall be specified as:
- a)severe, when the maximum value of the EDR cube root is greater than 0.7; b) moderate, when the maximum value of the EDR cube root is greater than 0.4 and less than or equal to 0.7; c) light, when the maximum value of the EDR cube root is greater than 0.1 and less than or equal to 0.4; and d) null (NIL) when the maximum value of the EDR cube root is less than or equal to 0.1.
EDR is an aircraft-independent measure of turbulence. However, the relationship between the EDR value and the perception of turbulence is a function of the aircraft type and the aircraft mass, altitude, configuration and airspeed. The EDR values given above describe turbulence severity levels for a medium-sized transport aircraft in normal en-route conditions (i.e., altitude, airspeed and weight).
2.6.3 Special aircraft reports Special aircraft reports on turbulence shall be made during any phase of the flight whenever the maximum value of the EDR cube root is greater than 0.4. Special aircraft reports on turbulence shall be made with reference to the 1-minute period immediately preceding the observation.
Both the average value and the maximum value of turbulence shall be observed. The average and maximum values shall be reported in terms of the EDR cube root.
Special aircraft reports shall be issued every minute until the time at which the maximum values of the EDR cube root are less than 0.4.
2.7 Humidity Humidity shall be reported rounded to the nearest whole percentage.
The value ranges and resolutions of the meteorological elements included in aircraft reports are indicated in Table A4-3.
3. EXCHANGE OF AIRCRAFT REPORTS 3.1 Responsibilities of meteorological watch offices 3.1.1 The meteorological watch office shall transmit without delay the special aircraft reports received by voice communications to the world area forecast centres (WAFC) and to the centres designated by regional air navigation agreement for the operation of the aeronautical fixed service and Internet-based services.
3.1.2 The meteorological watch office shall transmit without delay the special aircraft reports of pre-eruption volcanic activity, volcanic eruption or volcanic ash cloud received, to the relevant volcanic ash advisory centres.
3.1.3 When a special aircraft report is received at the meteorological watch office but the forecaster considers that the phenomenon which prompted the report is not expected to persist and, therefore, the issuance of a SIGMET message is not warranted, the special aircraft report shall be disseminated in the same manner as SIGMET messages are disseminated in accordance with Appendix 6 of this regulation, point 1.2.1, i.e., to meteorological watch offices, WAFCs and other meteorological offices, in accordance with the relevant regional air navigation agreement.
The template to be used for special aircraft reports uplinked to aircraft in flight is contained in Appendix 6 of this regulation, Table A6-1B.
3.2 Responsibilities of world area forecast centres Aircraft reports received at WAFCs shall be further disseminated as basic meteorological data.
The dissemination of basic meteorological data is normally carried out via the World Weather Watch Global Telecommunication System of the World Meteorological Organization (WMO).
3.3 Supplementary dissemination of aircraft reports When supplementary dissemination of aircraft reports is required to meet special aeronautical or meteorological needs, such dissemination shall be the subject of arrangements between the meteorological authorities concerned and shall be made as agreed between them.
3.4 Format of aircraft reports The exchange of aircraft reports shall be made in the form in which they are received.
4. SPECIFIC PROVISIONS RELATED TO THE REPORTING OF WIND SHEAR AND VOLCANIC ASH 4.1 Reporting of wind shear 4.1.1 When reporting aircraft observations of wind shear conditions encountered during the initial climb and approach phases of flight, the aircraft type shall be indicated.
4.1.2 The pilot-in-command shall notify the appropriate ATS unit as soon as possible whenever wind shear conditions reported or forecast are not encountered during the initial climb or approach phases of flight, unless the pilot-in-command is aware that a preceding aircraft has already reported this to the appropriate air traffic services unit.
4.2 Post-flight reporting of volcanic activity Detailed instructions for recording and reporting observations of volcanic activity are contained in Appendix 1 of the PANS-ATM (ICAO Doc. 4444).
4.2.1 On arrival of a flight at an aerodrome, the operator, or a flight crew member, shall deliver the completed report of volcanic activity without delay to the aerodrome meteorological office. If no aerodrome meteorological office exists, or if such an office is not readily accessible to arriving flight crew members, the completed form shall be handled 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 providing meteorological watch for the flight information region in which the volcanic activity was observed.
. The time of occurrence to be reported in accordance with Table A4-2. 2.
2. The turbulence to be reported in accordance with 2.6.3.
3. Thunderstorms obscured, embedded or widespread, or thunderstorms in squall lines.
4. Duststorm or sandstorm.
5. Pre-eruption volcanic activity or volcanic eruption.
APPENDIX 5 TECHNICAL SPECIFICATIONS RELATED TO FORECASTS 1. CRITERIA RELATED TO TAF 1.1 Format of TAF 1.1.1 TAF shall be issued in accordance with the template presented in Table A5-1 of this regulation and shall be disseminated in the TAF code form prescribed by the World Meteorological Organization (WMO).
The TAF code form is contained in the Manual on Codes (WMO No. 306), Volume I.1, Part A - Alphanumeric Codes.
1.1.2 Until 4 November 2020, TAF shall be disseminated in the IWXXM GML format, in addition to its dissemination in accordance with 1.1.1.
From 5 November 2020, TAF shall be disseminated in the IWXXM GML format, in addition to its dissemination in accordance with 1.1.1.
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 contained in the Manual on the Digital Exchange of Aeronautical Meteorological Information (ICAO Doc. 10003).
1.2 Inclusion of meteorological elements in TAF Guidance on operationally desirable accuracy of forecasts is provided in Attachment B.
1.2.1 Surface wind When forecasting surface wind, the expected prevailing direction shall be indicated. If 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 the abbreviation "VRB".
If a wind of less than 0.5 m/s (1 kt) is forecast, the forecast wind speed shall be indicated as calm. When the maximum forecast speed (gust) exceeds the forecast mean wind speed by 5 m/s (10 kt) or more, the maximum forecast wind speed shall be indicated. When a wind speed of 50 km/h (100 kt) or more is forecast, it shall be indicated as greater than 49 m/s (99 kt).
1.2.2 Visibility If the forecast visibility is less than 800 m, it shall be expressed in steps of 50 m; if it is 800 m or more but less than 5 km, in steps of 100 m; if it is 5 km or more but less than 10 km, in steps of one kilometre; and if it is 10 km or more, it shall be expressed as 10 km, except when conditions CAVOK are forecast to apply. The prevailing visibility shall be forecast. If visibility is forecast to vary in different directions and the prevailing visibility cannot be forecast, the lowest forecast visibility shall be indicated.
1.2.3 Weather phenomena If expected to occur at the aerodrome, one or more, up to a maximum of three, of the following weather phenomena or combinations thereof, together with their characteristics and, where applicable, their intensity, shall be forecast:
- freezing precipitation - freezing fog - moderate or heavy precipitation (including showers) - low drifting dust, sand or snow - blowing dust, sand or snow - duststorm - sandstorm - thunderstorm (with or without precipitation) - squall - funnel clouds (tornado or waterspout) - other weather phenomena indicated in Appendix 3 of this regulation, point 4.4.2.3, as agreed between the meteorological authorities, the competent ATS authorities and the operators concerned.
The expected end of these phenomena shall be indicated by the abbreviation "NSW".
1.2.4 Cloud Cloud amount shall be forecast using the abbreviations "FEW", "SCT", "BKN" or "OVC", as appropriate. If the sky is expected to remain or become obscured and it is not possible to forecast clouds, and vertical visibility information is available at the aerodrome, vertical visibility shall be forecast in the form "VV" followed by the forecast vertical visibility value. If several cloud layers or masses are forecast, their amount and height shall be included in the following order:
- a)the lowest layer or mass, regardless of amount, to be forecast as FEW, SCT, BKN or OVC, as appropriate; b) the next layer or mass immediately above covering more than 2/8, to be forecast as SCT, BKN or OVC, as appropriate; c) the next higher layer or mass immediately above covering more than 4/8, to be forecast as BKN or OVC, as appropriate; and d) cumulonimbus clouds and/or towering cumulus clouds, if not already indicated under a) to c).
Cloud information shall be limited to clouds significant for operations; when no such clouds are forecast and the abbreviation "CAVOK" is not appropriate, the abbreviation "NSC" shall be used.
1.2.5 Temperature When forecast temperatures are included in accordance with regional air navigation agreements, the maximum and minimum temperatures expected to occur during the period of validity of the TAF shall be indicated, together with their corresponding times of occurrence.
1.3 Use of change groups Guidance on the use of change and time indicators in TAF is contained 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, that are forecast to begin or end, or change in intensity:
- freezing fog - freezing precipitation - moderate or heavy precipitation (including showers) - thunderstorm (with precipitation) - duststorm - sandstorm.
1.3.2 The criteria used for the inclusion of change groups in TAF or for the amendment of TAF shall be based on the following:
- a)if the forecast mean surface wind direction changes by 60º or more, the mean speed before and/or after the change being 5 m/s (10 kt) or more; b) if the forecast mean surface wind speed changes by 5 m/s (10 kt) or more; c) if the forecast variation from the mean surface wind speed (gust) changes 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 forecast surface wind changes through values of operational significance. The threshold values shall be established by the meteorological authority in consultation with the competent ATS authority and the operators concerned, taking into account wind changes that:
- 1)require a change in the runways in use; and 2) indicate that the runway tailwind and crosswind components will change through values representing the main operating limits for typical aircraft operations at the aerodrome; e) when the forecast visibility improves and changes to, or passes through one or more of the following values, or when the forecast visibility deteriorates and passes through one or more of the following values:
- 1)150, 350, 600, 800, 1 500 or 3 000 m; or 2) 5 000 m when a significant number of flights are conducted 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 clouds (tornado or waterspout); g) when the forecast height of the base of the lowest cloud layer or mass of BKN or OVC extent lifts and changes to, or passes through one or more of the following values, or when the forecast height of the base of the lowest cloud layer or mass of BKN or OVC extent lowers and passes 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) when a significant number of flights are conducted in accordance with the visual flight rules; h) when the forecast amount of a cloud layer or mass below 450 m (1 500 ft) changes:
- 1)from NSC, FEW or SCT to BKN or OVC; or 2) from BKN or OVC to NSC, FEW or SCT; i) when the forecast vertical visibility improves and changes to, or passes through one or more of the following values, or when the forecast vertical visibility deteriorates and changes to, or passes through one or more of the following values: 30, 60, 150 or 300 m (100, 200, 500 or 1 000 ft); and j) other criteria based on local aerodrome operating minima, agreed between the meteorological authorities and the operators concerned.
Other criteria based on local aerodrome operating minima shall be considered in parallel with similar criteria for the issuance of SPECI prepared in response to Appendix 3 of this regulation, point 2.3.3 h).
1.3.3 When a change in any of the elements referred to in Subpart F, RAC-03.430, is required to be indicated in accordance with the criteria presented in 1.3.2, the change indicators "BECMG" or "TEMPO" shall be used, followed by the period of time during which the change is expected to occur. The period of time shall be indicated as the beginning and end of the period in whole UTC hours. Only those elements for which a significant change is expected shall be included after a change indicator. However, in the case of significant changes in respect of cloud, all cloud groups, including layers or masses for which no change is expected, shall be indicated.
1.3.4 The change indicator "BECMG" and the associated time group shall be used to describe changes expected to reach, or pass through, specified threshold values at a regular or irregular rate and at an unspecified time within the time period. Normally the time period should not exceed two hours and in no case shall it exceed four hours.
1.3.5 The change indicator "TEMPO" and the associated time group shall be used to describe the expected frequency or infrequency of temporary fluctuations in meteorological conditions that reach, or pass through, a specified threshold value and have a duration of less than one hour in each instance and, in the aggregate, cover less than half of the forecast period during which the fluctuations are expected to occur. If the temporary fluctuation is expected to last one hour or more, the change group "BECMG" shall be used in accordance with 1.3.4, or the validity period shall be subdivided in accordance with 1.3.6.
1.3.6 If a set of prevailing weather conditions is expected to change significantly and more or less completely to a different set of conditions, the period of validity shall be subdivided into independent periods using the abbreviation "FM", followed immediately by a six-figure time group in days, hours and minutes UTC, indicating the expected time of the change.
The subdivided period following the abbreviation "FM" shall be self-contained and all forecast conditions given before the abbreviation shall be superseded by the conditions following the abbreviation.
1.4 Use of probability groups The probability of an alternative value or values for one or more elements of the forecast shall be indicated, when necessary, by the abbreviation "PROB" followed by the probability in tens of per cent, and the period of time during which the alternative value or values are expected to apply.
Information concerning probability must be reported after the forecast of the corresponding element or elements. The probability of temporary fluctuations in the forecast meteorological conditions must be indicated, as necessary, using the abbreviation "PROB" followed by the probability in tens of percent, and before the change indicator "TEMPO" and the corresponding time group. Any alternative value or change with a probability of less than 30% should not be considered significant enough to indicate. If the probability of an alternative value or a change is 50% or higher, it should not be considered, for aeronautical purposes, simply as a probability, but rather must be indicated, as necessary, using the change indicators "BECMG" or "TEMPO" or by a subdivision of the validity period using the abbreviation "FM". The probability group must not be used as a qualifier for the change indicator "BECMG", nor as the time indicator "FM".
1.5 Number of probability and change groups The number of probability and change groups must be kept to a minimum and should normally be less than five groups.
1.6 Dissemination of TAFs TAFs and their amendments are disseminated to the international OPMET data banks and to the centers designated by regional air navigation agreement for the operation of the aeronautical fixed service satellite distribution system and Internet-based services, in accordance with a regional air navigation agreement.
2. CRITERIA CONCERNING TREND-TYPE FORECASTS 2.1 Format of trend-type forecasts Trend-type forecasts are issued in accordance with the templates presented in Appendix 3, Tables A3-1 and A3-2 of this RAC. The units and scales used in the trend-type forecast are the same as those used in the report to which it is appended.
Examples of trend-type forecasts are provided in Appendix 3 of this RAC.
2.2 Inclusion of meteorological elements in trend-type forecasts 2.2.1 General provisions Trend-type forecasts indicate significant changes with respect to one or more of the elements: surface wind, visibility, meteorological conditions, and clouds. Only those elements for which a significant change is expected are included. However, in the case of significant changes in clouds, all cloud groups are indicated, including cloud layers or masses not expected to change. In the case of a significant change in visibility, the phenomenon causing the reduction in visibility is also indicated. When no change is expected to occur, this is indicated using the term "NOSIG".
2.2.2 Surface wind Trend-type forecasts indicate changes in surface wind that involve:
- a)a change in the mean wind direction of 60° or more, with a mean speed of 5 m/s (10 kt) or more, before or after the change; b) a change in the mean wind speed of 5 m/s (10 kt) or more; and c) changes in the wind passing through values of importance for operations. The meteorological authority must establish threshold values in consultation with the competent ATS authority and the operators concerned, taking into account changes in the wind that:
- 1)require a change in the runways in use; and 2) indicate that the tailwind and crosswind components on the runway change, passing through values representing the main operating limits for typical aircraft operating at the aerodrome.
2.2.3 Visibility When visibility is expected to improve or pass through one or more of the following values, or when visibility is expected to deteriorate and pass through one or more of the following values: 150, 350, 600, 800, 1,500, or 3,000 m, the change is indicated in the trend-type forecasts. When a significant number of flights are conducted in accordance with visual flight rules, the forecast also indicates changes reaching or passing through 5,000 m.
In trend-type forecasts appended to local routine and special reports, visibility refers to the forecast visibility along the runways; in trend-type forecasts appended to METAR and SPECI, visibility refers to the forecast prevailing visibility.
2.2.4 Meteorological phenomena 2.2.4.1 Trend-type forecasts indicate the expected onset, cessation, or change in intensity of one or more of the following meteorological phenomena or a combination thereof:
- freezing precipitation - moderate or heavy precipitation (including showers) - thunderstorm (with precipitation) - duststorm - sandstorm - other meteorological phenomena listed in Appendix 3 of this RAC, section 4.4.2.3, as agreed between the appropriate meteorological authority and the ATS authority and relevant operators.
2.2.4.2 The trend-type forecast indicates the expected onset or cessation of one or more of the following meteorological 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 must be a maximum of three.
2.2.4.4 The expected cessation of these phenomena must be indicated by the abbreviation "NSW".
2.2.5 Clouds When the height of the base of a cloud layer of BKN or OVC extent is expected to increase 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 decrease 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), changes are indicated in the trend-type forecasts. When the height of the base of a cloud layer is expected to descend below or ascend above 450 m (1,500 ft), the trend-type forecasts also indicate changes in the cloud amount from FEW or SCT increasing to BKN or OVC, or changes from BKN or OVC decreasing to FEW or SCT. When no clouds of operational significance are forecast and "CAVOK" is not appropriate, the abbreviation "NSC" is used.
2.2.6 Vertical visibility If the sky is expected to remain obscured or to become obscured, and observations of vertical visibility are available at the aerodrome, and the vertical visibility is forecast to improve and change 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), the changes must be indicated in the trend-type forecasts.
2.2.7 Additional criteria For the indication of changes based on local aerodrome operating minima, criteria other than those specified in 2.2.2 to 2.2.6 are used, by agreement between the meteorological authorities and the operator concerned.
2.3 Use of change groups Guidance on the use of change indicators in trend-type forecasts is provided in Appendix 3 of this RAC, in Table A3-3.
2.3.1 When a change is expected to occur, the trend-type forecast begins with one of the change indicators "BECMG" or "TEMPO".
2.3.2 The change indicator "BECMG" is used to describe forecast changes if meteorological conditions are expected to reach or pass through specified values at a regular or irregular rate. The period during which the change is forecast, or the time of the forecast, is indicated using the abbreviations "FM", "TL", or "AT", as appropriate, each followed by a time group in hours and minutes. If the change is forecast to begin and end completely within the trend-type forecast period, the beginning and end of the change are indicated using the abbreviations "FM" and "TL", respectively, together with their corresponding time groups. If the change is forecast to begin at the start of the trend-type forecast period but to end before the end of that period, the abbreviation "FM" and its corresponding time group are omitted, and only the abbreviation "TL" and its corresponding time group are used. If the change is forecast to begin during the trend-type forecast period and end at the end of that period, the abbreviation "TL" and its corresponding time group are omitted, and only the abbreviation "FM" and its corresponding time group are used. If the change is forecast to occur at a specific time during the trend-type forecast period, the abbreviation "AT" is used, followed by its corresponding time group. If the change is forecast to begin at the start of the trend-type forecast period and end at the end of that period, or if the change is forecast to occur within the trend-type forecast period but the time is uncertain, the abbreviations "FM", "TL", or "AT" and their corresponding time groups are omitted, and only the change indicator "BECMG" is used.
2.3.3 The change indicator "TEMPO" is used to describe temporary fluctuations in forecast meteorological conditions that reach or pass through specified values and last less than one hour in each instance and, in total, cover less than half of the period during which the fluctuations are forecast. The period during which the temporary fluctuations are forecast to occur is indicated using the abbreviations "FM" or "TL", as appropriate, each followed by a time group in hours and minutes. If the period of temporary fluctuations in meteorological conditions is forecast to begin and end completely within the trend-type forecast period, the beginning and end of the temporary fluctuation period are indicated using the abbreviations "FM" and "TL", respectively, with their corresponding time groups. If the period of temporary fluctuations is forecast to begin at the start of the trend-type forecast period but to end before the end of that period, the abbreviation "FM" and its corresponding time group are omitted, and only the abbreviation "TL" and its corresponding time group are used. If the period of temporary fluctuations is forecast to begin during the trend-type forecast period and end at the end of that period, the abbreviation "TL" and its corresponding time group are omitted, and only the abbreviation "FM" and its corresponding time group are used. If the period of temporary fluctuations is forecast to begin at the start of the trend-type forecast period and end at the end of that period, the abbreviations "FM" and "TL" and their corresponding time groups are omitted, and only the change indicator "TEMPO" is used.
2.4 Use of probability indicator The indicator "PROB" must not be used in trend-type forecasts.
3. CRITERIA CONCERNING FORECASTS FOR TAKE-OFF 3.1 Format of forecasts for take-off The form of the forecast must be as agreed between the meteorological authority and the operator concerned. The order of the elements and the terminology, units, and scales used in take-off forecasts must be the same as those used in the reports for the same aerodrome.
3.2 Amendments to forecasts for take-off The criteria for issuing amendments to forecasts for take-off concerning surface wind direction and speed, temperature, and pressure, as well as any other locally agreed elements, must be agreed between the meteorological authority and the operators concerned. Such criteria must be consistent with those established for special aerodrome reports in accordance with Appendix 3 of this RAC, section 2.3.1.
4. CRITERIA CONCERNING AREA FORECASTS FOR LOW-LEVEL FLIGHTS 4.1 Format and content of GAMET area forecasts When prepared in GAMET format, area forecasts must include two sections: Section I concerning information on en-route phenomena hazardous to low-level flights, prepared to support the issuance of AIRMET information, and Section II concerning additional information required by low-level flights. The content and order of elements in a GAMET area forecast must be prepared in accordance with the template provided in Table A5-3. Section II must include additional elements in accordance with regional air navigation agreements. Elements already covered in a SIGMET message must be omitted from GAMET area forecasts.
4.2 Amendments to GAMET area forecasts In the event that meteorological phenomena hazardous to low-level flights were included in the GAMET area forecast and the forecast phenomenon does not occur or ceases to be forecast, a GAMET AMD must be issued, amending only the meteorological element in question.
Instructions regarding the issuance of AIRMET information to amend area forecasts concerning meteorological phenomena hazardous to low-level flights are provided in Appendix 6 of this RAC.
4.3 Content of area forecasts for low-level flights issued in chart form 4.3.1 When a chart form is used for area forecasts for low-level flights, the forecast of winds and temperatures aloft must be issued for points separated by no more than 500 km (300 NM) and for at least the following altitudes: 600, 1,500, and 3,000 m (2,000, 5,000, and 10,000 ft), and 4,500 m (15,000 ft) in mountainous areas.
4.3.2 When a chart form is used for area forecasts for low-level flights, the forecast of SIGWX phenomena must be issued as a low-level SIGWX forecast up to flight level 100 (or up to flight level 150 in mountainous areas, or higher, if necessary). Low-level SIGWX forecasts must cover the following:
- a)phenomena warranting the issuance of a SIGMET message as established in Appendix 6 of this RAC and that are expected to affect low-level flights; and b) the elements contained in area forecasts for low-level flights as established in Table A5-3 of this RAC, except for elements relating to:
- 1)winds aloft and temperatures aloft; and 2) forecast QNH.
Guidance on the use of the terms "ISOL", "OCNL", and "FRQ" in reference to cumulonimbus and towering cumulus clouds and thunderstorms is provided in Appendix 6.
4.4 Exchange of area forecasts for low-level flights Area forecasts for low-level flights prepared to support the issuance of AIRMET reports must be exchanged between aerodrome meteorological offices and/or meteorological watch offices responsible for issuing flight documentation for low-level flights in the corresponding flight information regions.
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 if applicable.
5. One or more groups, up to a maximum of three, in accordance with 1.2.3.
6. To be included if applicable in accordance with 1.2.3. No qualifier for moderate intensity.
7. Meteorological phenomena must be included in accordance with 1.2.3.
8. Up to four cloud layers in accordance with 1.2.4.
9. Include in accordance with 1.2.5, with a maximum of 4 temperatures (two maximum temperatures and two minimum temperatures).
10. Include in accordance with 1.3, 1.4, and 1.5. 11. Must be used with FM only.
1. Fictitious location.
2. Free text describing well-known geographical locations must be kept to a minimum.
3. The location of CB or TCU must be specified in addition to any extensive area of broken or overcast clouds, as given in the example. 4. Repeat as necessary, separated by commas. 5. When no elements are included in Section I.
APPENDIX 6 TECHNICAL SPECIFICATIONS CONCERNING SIGMET AND AIRMET INFORMATION, AERODROME WARNINGS, AND WIND SHEAR WARNINGS AND ALERTS The data type designators used in the abbreviated headings of SIGMET, AIRMET, tropical cyclone advisories, and volcanic ash advisories are provided in the Manual on the Global Telecommunication System (WMO No. 386).
1. SPECIFICATIONS CONCERNING SIGMET INFORMATION 1.1 Format of SIGMET messages 1.1.1 The content and order of elements in SIGMET messages must conform to the template provided in Table A6-1a of this RAC.
1.1.2 Messages containing SIGMET information are identified by the indicator "SIGMET".
1.1.3 The sequence number referred to in the template in Table A6-1a of this RAC corresponds to the number of SIGMET messages issued for the flight information region (FIR) since 0001 UTC on the day in question. Meteorological watch offices whose area of responsibility encompasses more than one FIR and/or control area (CTA) issue separate SIGMET messages for each FIR or CTA within their area of responsibility.
1.1.4 In accordance with the template in Table A6-1a of this RAC, only one of the following phenomena is included in a SIGMET message, using the abbreviations indicated below:
At cruising levels (regardless of altitude):
1.1.5 SIGMET information must not contain unnecessary descriptive text. When describing the meteorological phenomena for which the SIGMET message is issued, no descriptive text beyond that indicated in 1.1.4 must be included. In SIGMET information concerning thunderstorms or tropical cyclones, no reference is made to the associated turbulence and icing phenomena.
1.1.6 Until 4 November 2020, SIGMET information must be disseminated in IWXXM GML format, in addition to disseminating this information in accordance with 1.1.1.
From 5 November 2020, SIGMET information is disseminated in IWXXM GML format, in addition to disseminating this information in accordance with 1.1.1.
Technical specifications for IWXXM are provided in the Manual on Codes (WMO No. 306), Volume 1.3, Part D - Representation derived from data models. Guidance on the implementation of IWXXM is provided in the Manual on the Digital Exchange of Aeronautical Meteorological Information (ICAO Doc 10003).
1.1.7 When issued in graphical format, the SIGMET must conform to the specifications of Appendix 1 of this RAC, including the use of applicable symbols and/or abbreviations.
1.2 Dissemination of SIGMET messages 1.2.1 SIGMET messages are disseminated to meteorological watch offices, WAFCs, and other meteorological offices, in accordance with the regional air navigation agreement. SIGMET messages concerning volcanic ash are also disseminated to volcanic ash advisory centers.
1.2.2 SIGMET messages are distributed to the international OPMET data banks and to the centers designated by regional air navigation agreement for the operation of the aeronautical fixed service and Internet-based services, in accordance with a regional air navigation agreement.
2.1.5 AIRMET information must not contain unnecessary descriptive text. When describing the meteorological phenomena for which the AIRMET message is issued, no description beyond that indicated in 2.1.4 must be included. AIRMET information on thunderstorms or cumulonimbus clouds makes no reference to the resulting turbulence and icing.
Specifications for SIGMET information also applicable to low-level flights are provided in 1.1.4.
2.1.6 Until 4 November 2020, AIRMET information must be disseminated in IWXXM GML format, in addition to disseminating this information in accordance with 2.1.1.
From 5 November 2020, AIRMET information is disseminated in IWXXM GML format, in addition to disseminating this information in accordance with 2.1.1.
Technical specifications for IWXXM are provided in the Manual on Codes (WMO No. 306), Volume 1.3, Part D - Representation derived from data models. Guidance on the implementation of IWXXM is provided in the Manual on the Digital Exchange of Aeronautical Meteorological Information (ICAO Doc 10003).
2.2 Dissemination of AIRMET messages 2.2.1 AIRMET messages must be disseminated to meteorological watch offices in adjacent FIRs and to other meteorological watch offices or aerodrome meteorological offices, as agreed between the relevant meteorological authorities.
2.2.2 AIRMET messages must be transmitted to the international operational meteorological data banks and to the centers designated by regional air navigation agreement for the operation of the aeronautical fixed service and Internet-based services, in accordance with a regional air navigation agreement.
3. SPECIFICATIONS CONCERNING SPECIAL AIR-REPORTS This appendix deals with the uplink of special air-reports. General specifications concerning special air-reports are provided in Appendix 4 of this RAC.
Special air-reports must be uplinked for 60 minutes after their issuance.
Information on winds and temperatures included in automatic special air-reports must not be uplinked to other aircraft in flight.
4. DETAILED CRITERIA CONCERNING SIGMET AND AIRMET MESSAGES AND SPECIAL AIR-REPORTS (UPLINK) 4.1 Identification of the flight information region In cases where airspace is subdivided into an FIR and an upper flight information region (UIR), the SIGMET must be identified by the location indicator of the air traffic services unit serving the FIR.
The SIGMET message applies to the entire airspace within the lateral limits of the FIR, i.e., to the FIR and the UIR. The particular areas 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 concerning phenomena included in SIGMET and AIRMET messages and special air-reports (uplink) 4.2.1 Thunderstorms and cumulonimbus clouds in an area must be considered as:
- a)obscured (OBSC) if they are obscured by haze or smoke or cannot be readily observed due to darkness; b) embedded (EMBD) if they are embedded within cloud layers and cannot be readily recognized; c) isolated (ISOL) if they consist of individual features that affect or are forecast to affect an area with a maximum spatial coverage of less than 50% of the area of interest (at a fixed time or during the validity period); and d) occasional (OCNL) if they consist of well-separated features that affect or are forecast to affect an area with a maximum spatial coverage between 50% and 75% of the area of interest (at a fixed time or during the validity period).
4.2.2 An area must be considered as having frequent thunderstorms (FRQ) if within that area there is little or no separation between adjacent thunderstorms, with a maximum spatial coverage greater than 75% of the area affected, or forecast to be affected, by the phenomenon (at a fixed time or during the validity period).
4.2.3 The squall line (SQL) must indicate a thunderstorm along a line with little or no space between the clouds.
4.2.4 Hail (GR) must be used as a further description of the thunderstorm, if necessary.
4.2.5 Only severe and moderate turbulence (TURB) must be mentioned for: low-level turbulence associated with strong surface winds; rotor streaming; or turbulence whether in cloud or not in cloud (CAT). Turbulence must not be used in connection with convective clouds.
4.2.6 Turbulence is considered:
- a)severe whenever the maximum value of the cube root of EDR is greater than 0.7; and b) moderate whenever the maximum value of the cube root of EDR is greater than 0.4 and less than or equal to 0.7.
4.2.7 Severe and moderate icing (ICE) must be mentioned as icing in clouds other than convective clouds. Freezing rain (FZRA) must be mentioned as severe icing conditions caused by freezing rain.
4.2.8 Mountain waves (MTW) must be considered as:
- a)severe, when an accompanying downdraft of 3.0 m/s (600 ft/min) or more is observed or forecast, or if severe turbulence is observed or forecast; and b) moderate, when a downdraft of 1.75-3.0 m/s (350-600 ft/min) is observed or forecast, or when moderate turbulence is observed or forecast.
4.2.9 Sandstorms and duststorms must be considered:
- a)severe when visibility is less than 200 m and the sky is obscured; and b) moderate when visibility:
- 1)is less than 200 m and the sky is not obscured; or 2) is between 200 m and 600 m.
5. SPECIFICATIONS CONCERNING AERODROME WARNINGS 5.1 Format and dissemination of aerodrome warnings 5.1.1 Aerodrome warnings must be issued to interested parties in accordance with the template in Table A6-2, when required by operators or aerodrome services, and are disseminated according to local arrangements.
5.1.2 The sequence number referred to in the template in Table A6-2 must correspond to the number of aerodrome warnings issued for the aerodrome since 0001 UTC on the day in question.
5.1.3 In accordance with the template in Table A6-2, aerodrome warnings must refer to actual or expected occurrences of one or more of the following phenomena:
- tropical cyclone [the tropical cyclone must be included if the mean surface wind speed over a 10-minute period at the aerodrome is expected to be 17 m/s (34 kt) or more] - thunderstorm - hail - snow (including expected or observed snow accumulation) - freezing precipitation - hoar frost or rime - sandstorm - duststorm - blowing sand or dust - strong surface wind and gusts - squall - frost - volcanic ash - tsunamis - volcanic ash deposition - toxic chemicals - other phenomena as locally agreed.
Aerodrome warnings relating to the actual or expected occurrence of a tsunami are not required when a national public safety plan for tsunamis has been integrated into the corresponding "at-risk" aerodrome.
5.1.4 The use of text in addition to the abbreviations listed in the template presented in Table A6-2 must be kept to a minimum. Additional text must be prepared in abbreviated plain language, using approved ICAO abbreviations and numerical values. If approved ICAO abbreviations are not available, plain language text in the English language must be used.
5.2 Quantitative criteria for aerodrome warnings When it is necessary to establish quantitative criteria for issuing aerodrome warnings covering criteria such as the maximum expected wind speed or the total expected snowfall, such criteria used must be as agreed between the aerodrome meteorological office and the users concerned.
6. SPECIFICATIONS CONCERNING WIND SHEAR WARNINGS 6.1 Detection of wind shear Evidence of the existence of wind shear must be derived from:
- a)ground-based remote-sensing wind shear equipment, such as Doppler radar; b) ground-based wind shear detection equipment, such as a network of surface wind or pressure sensors arranged to monitor a specific runway or runways and their corresponding approach and departure paths; c) aircraft observations during the initial climb or approach phases of flight, in accordance with Subpart E; or d) other meteorological information, such as from suitable sensors located on masts or towers in the vicinity of the aerodrome or in nearby areas with elevated terrain.
Normally, wind shear conditions are associated with the following phenomena:
- thunderstorms, microbursts, funnel clouds (tornadoes or waterspouts), and gust fronts - frontal surfaces - strong surface winds associated with local topography - sea-breeze fronts - mountain waves (including low-level rotor clouds in the terminal area) - low-level temperature inversions.
6.2 Format and dissemination of wind shear warnings and alerts In accordance with the templates in Appendix 3 of this RAC in Tables A3-1 and A3-2, wind shear data must be included as supplementary information in local routine reports, local special reports, and METAR and SPECI.
6.2.1 Wind shear advisories shall be issued in accordance with the template in Table A6-3 of this RAC and disseminated to interested parties according to local arrangements.
6.2.2 The sequence number mentioned in the template in Table A6-3 of this RAC corresponds to the number of wind shear advisories issued for the aerodrome starting from 0001 UTC on the day in question.
6.2.3 The use of text additional to the abbreviations in the list from the template presented in Table A6-3 of this RAC shall be kept to a minimum. Additional text shall be prepared in plain abbreviated language using approved ICAO abbreviations and numerical values. If approved ICAO abbreviations are not available, text in plain English language shall be used.
6.2.4 When an aircraft report is used in the preparation of a wind shear advisory or a previously issued advisory is confirmed, the corresponding unmodified aircraft report shall be disseminated to interested parties, in addition to the aircraft type, according to local arrangements.
As a consequence of encounters reported by arriving and departing aircraft, two distinct wind shear advisories could exist: one for arriving aircraft and another for departing aircraft.
Specifications for reporting wind shear intensity are still under development. However, it is acceptable for pilots, when reporting wind shear, to characterize it using expressions such as "moderate" (moderada), "strong" (fuerte), or "very strong" (muy fuerte), which are based largely on a subjective assessment of the intensity of the wind shear they have encountered.
6.2.5 Wind shear alerts shall be disseminated to interested parties from automated ground-based wind shear detection or remote-sensing equipment, in accordance with local arrangements.
6.2.6 When microbursts are observed, communicated by pilots, or reported by ground-based wind shear detection or remote-sensing equipment, the wind shear advisory and alert shall include a specific reference to the microburst.
6.2.7 When information from ground-based wind shear detection or remote-sensing equipment is used to prepare a wind shear alert, the alert shall refer, if possible, to specific runway sections and distances along the approach or departure paths, as agreed between the meteorological authorities, the competent ATS authority, and the relevant operators.
APPENDIX 7 TECHNICAL SPECIFICATIONS RELATING TO AERONAUTICAL CLIMATOLOGICAL INFORMATION 1. PROCESSING OF AERONAUTICAL CLIMATOLOGICAL INFORMATION Meteorological observations for regular and alternate aerodromes shall be collected, processed, and stored in a format suitable for the preparation of aerodrome climatological information.
2. EXCHANGE OF AERONAUTICAL CLIMATOLOGICAL INFORMATION Aeronautical climatological information shall be exchanged, upon request, between meteorological authorities. Operators and other aeronautical users desiring such information shall normally request it from 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 shall provide, as appropriate:
- a)mean values and variations thereof, including maximum and minimum values, of meteorological elements (air temperature); and/or b) the frequency of occurrence of present weather phenomena affecting flight operations at the aerodrome (sandstorm); and/or c) the frequency of occurrence of specific values of one element or a combination of two or more elements (a combination of low visibility and low clouds).
3.1.2 Aerodrome climatological tables shall include the information required for the preparation of aerodrome climatological summaries, in accordance with section 3.2.
3.2 Aerodrome climatological summaries Aerodrome climatological summaries shall cover the following:
- a)frequency of occurrence of runway visual range/visibility or the height of the base of the lowest cloud layer of BKN or OVC extent being below specified values, at specified times; b) frequency of occurrence of visibility being below specified values, at specified times; c) frequency of occurrence of the height of the base of the lowest cloud layer of BKN or OVC extent being below specified values, at specified times; d) frequency of occurrence of concurrent wind direction and speed being within specified value ranges; e) frequency of occurrence of surface temperature being within specified 5°C intervals, at specified times; and f) mean value and variations from the mean, including maximum and minimum values of meteorological elements, when necessary for operational planning, including for take-off performance calculations.
The models for climatological summaries related to a) to e) are contained in the Technical Regulations (WMO-No. 49), Volume II - Meteorological Service for International Air Navigation, Part III.
APPENDIX 8 TECHNICAL SPECIFICATIONS RELATING TO SERVICES PROVIDED TO OPERATORS AND FLIGHT CREW MEMBERS In Appendix 1 of this RAC, the specifications relating to flight documentation (including maps and model forms) are presented.
1. MEANS OF PROVIDING METEOROLOGICAL INFORMATION AND FORMAT 1.1 Meteorological information is provided to operators and flight crew members by one or more of the following means, agreed between the meteorological authority and the interested operator, without the order indicated below implying any priority:
- a)written or printed texts, including specified maps and forms; b) data in digital form; c) verbal briefing; d) consultation; e) visual display of information; or f) in lieu of items a) to e), through an automated pre-flight information system providing self-briefing and flight documentation service but retaining access to consultation by operators and aircraft crew members with the aerodrome meteorological office, as necessary, in accordance with section 5.1.
1.2 The meteorological authority, in consultation with the operator, shall determine:
- a)the type and form of presentation of the meteorological information to be provided; and b) the methods and means for providing such information.
1.3 At the request of the operator, the meteorological information provided for flight planning shall include data for determining the lowest usable flight level.
2. SPECIFICATIONS RELATING TO INFORMATION FOR PRE-FLIGHT PLANNING AND IN-FLIGHT RE-PLANNING 2.1 Format of gridded information in altitude The gridded information in altitude provided by the world area forecast centres (WAFC) for pre-flight planning and in-flight re-planning shall be presented in GRIB code form.
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 significant weather information The significant weather information provided by the WAFCs for pre-flight planning and in-flight re-planning shall be presented in BUFR code form.
The BUFR code form is contained in the Manual on Codes (WMO-No. 306), Volume I.2, Part B - Binary Codes.
2.3 Specific needs of helicopter operations Meteorological information for pre-flight planning and in-flight re-planning by operators of helicopters operating to offshore structures shall include data covering all layers from sea level up to flight level 100. Particular mention shall be made of the expected surface visibility, the amount, type (if available), base and top of clouds below flight level 100, sea state and sea surface temperature, mean sea level pressure, and the occurrence or expected occurrence of turbulence and icing, as stipulated by regional air navigation agreement.
3. SPECIFICATIONS RELATING TO VERBAL BRIEFING AND CONSULTATIONS 3.1 Information to be presented The information presented shall be readily accessible to flight crew members or other flight operations personnel.
4. SPECIFICATIONS RELATING TO FLIGHT DOCUMENTATION 4.1 Presentation of information 4.1.1 Flight documentation related to forecasts of wind and temperature aloft and SIGWX phenomena shall be presented in the form of maps.
For low-level flights, GAMET area forecasts shall be used as an alternative form.
The model maps and forms used in the preparation of flight documentation are contained in Appendix 1 of this RAC. The World Meteorological Organization (WMO) develops these models and preparation methods based on relevant operational requirements established by ICAO.
4.1.2 Flight documentation related to route-specific concatenated forecasts of wind and temperature aloft shall be provided when so agreed between the meteorological authority and the interested operator.
Guidance on the design, formulation, and use of concatenated maps is contained in the Manual on Aeronautical Meteorological Methods (Doc 8896).
4.1.3 METAR and SPECI (including trend forecasts issued in accordance with regional air navigation agreements), TAF, GAMET, SIGMET and AIRMET, advisory information on volcanic ash, tropical cyclones, and space weather conditions shall be presented according to the templates contained in Appendices 1, 2, 3, 5, and 6 of this RAC. Information of this type received from other meteorological offices shall be included in the flight documentation unchanged.
Examples of the presentation form for METAR/SPECI and TAF are contained in Appendix 1 of this RAC.
4.1.4 Location indicators and abbreviations used shall be explained in the flight documentation.
4.1.5 The forms and map legends included in the flight documentation shall be printed in Spanish, French, English, or Russian.
Approved abbreviations shall be used, when pertinent. The units used for each element shall be indicated; these shall conform to those established in ICAO Annex 5.
4.2 Flight documentation maps 4.2.1 Characteristics of maps 4.2.1.1 Maps included in flight documentation shall be highly clear and legible and have the following physical characteristics:
- a)for convenience, maps shall be approximately 42 × 30 cm (standard A3 size) maximum and approximately 21 × 30 cm (standard A4 size) minimum. The choice between these sizes shall depend on the extent of the routes and the number of details required to be indicated on the maps, as agreed between the meteorological authorities and the interested users; b) principal geographical features, for example, coastlines, major rivers, and lakes, shall be represented in a way that they are easily recognizable; c) with respect to computer-generated maps, meteorological information shall take precedence over basic cartographic information and override it where there is overlap between the two; d) principal aerodromes shall be indicated by a dot and identified by the first letter of the name of the city served by the aerodrome, as it appears in the AOP Table of the relevant regional air navigation plan; e) a geographic grid with meridians and parallels represented by dotted lines every 10° of latitude and longitude shall be presented; the spacing between dots shall be 1°; f) latitude and longitude values shall be indicated at several points throughout the map (i.e., not only in the margins); and g) markings on flight documentation maps shall be clear and simple and unambiguously indicate the name of the world area forecast centre, or for information not produced by the world area forecast system (WAFS), the type of map, the date and validity period, and, if necessary, the types of units used unambiguously.
4.2.1.2 The meteorological information contained in the flight documentation shall be represented as follows:
- a)winds shall be indicated on maps by arrows with shaded feathers and pennants on a sufficiently dense grid; b) temperatures shall be indicated by figures on a sufficiently dense grid; c) wind and temperature data selected from the data received from a world area forecast centre shall be represented on a grid sufficiently dense in latitude and longitude; and d) wind arrows shall have precedence over temperatures, and both shall stand out against the map background.
4.2.1.3 For short-distance flights, maps at the required scale of 1:15 × 106 covering limited areas shall be prepared, to the extent necessary.
4.2.2 Set of maps to be provided 4.2.2.1 The minimum number of maps for flights between flight level 250 and 630 shall include a high-level SIGWX map (from flight level 250 to flight level 630) and a wind and temperature forecast map at 250 hPa. The maps actually supplied for pre-flight and in-flight planning and for flight documentation shall be as agreed between the meteorological authorities and the interested users.
4.2.2.2 The maps provided shall be generated from the digital forecasts provided by the WAFCs, when these forecasts cover the intended flight path with respect to time, altitude, and geographical extent, unless otherwise agreed between the meteorological authority and the interested operator.
4.2.3 Indications of height In flight documentation, indications of height shall be given as follows:
- a)all references to en-route meteorological conditions, such as height indications for upper winds, turbulence, or cloud bases and tops, shall preferably be expressed in flight levels, but may also be expressed in pressure, altitude, or, for low-level flights, in height above ground level; and b) all references to aerodrome meteorological conditions, such as height indications for cloud bases, shall be expressed as height above the aerodrome elevation.
4.3 Specifications relating to low-level flights 4.3.1 In map form When forecasts are provided in map form, the documentation for low-level flights, including those operated in accordance with visual flight rules, conducted up to flight level 100 (or up to flight level 150 in mountainous areas, or higher, if necessary), shall contain the following flight-relevant information:
- a)information from pertinent SIGMET and AIRMET messages; b) wind and temperature aloft maps as indicated in Appendix 5 of this RAC, section 4.3.1; and c) significant weather maps as indicated in Appendix 5 of this RAC, section 4.3.2.
4.3.2 In plain abbreviated language When forecasts are not provided in map form, the documentation for low-level flights, including those operated in accordance with visual flight rules, conducted up to flight level 100 (up to flight level 150 in mountainous areas, or higher, if necessary), shall contain the following flight-relevant information:
- a)SIGMET and AIRMET information; and b) GAMET area forecasts.
An example of a GAMET area forecast is contained in Appendix 5 of this RAC.
5. SPECIFICATIONS RELATING TO AUTOMATED PRE-FLIGHT INFORMATION SYSTEMS FOR VERBAL BRIEFING, CONSULTATIONS, FLIGHT PLANNING, AND FLIGHT DOCUMENTATION 5.1 Access to systems Automated pre-flight information systems offering self-briefing devices shall provide access for operators and flight crew members to consult, if necessary, with an aerodrome meteorological office by telephone or other suitable means of telecommunication.
5.2 Detailed specifications of systems Automated pre-flight information systems providing meteorological information for self-briefing, pre-flight planning, and flight documentation shall:
- a)ensure the constant and timely updating of the system database and monitor the validity and integrity of the stored meteorological information; b) permit all operators and flight crew members, as well as all other interested aeronautical users, to access the system through a suitable means of telecommunication; c) employ access and interrogation procedures based on plain abbreviated language and, as appropriate, ICAO location indicators and data type designators of aeronautical meteorological codes prescribed by WMO, or based on a menu-driven user interface, or other appropriate mechanisms agreed between the meteorological authority and the operators concerned; and d) provide for rapid response to a user request for information.
ICAO abbreviations and codes and location indicators are contained respectively in the Procedures for Air Navigation Services - ICAO Abbreviations and Codes (PANS-ABC, Doc. 8400) and in Location Indicators (ICAO Doc 7910). The data type designators of aeronautical meteorological codes are contained in the Manual on the Global Telecommunication System (WMO-No. 386).
6. SPECIFICATIONS RELATING TO INFORMATION FOR AIRCRAFT IN FLIGHT 6.1 Supply of information requested by an aircraft in flight If an aircraft in flight requests meteorological information, the aerodrome meteorological office or meteorological watch office receiving the request shall take the necessary measures to provide 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 Meteorological information for planning by the operator intended for aircraft in flight shall be provided during the course of the flight and generally contain all or some of the following elements:
- a)METAR and SPECI (including trend forecasts issued according to regional air navigation agreements); b) TAF and amendments thereto; c) SIGMET and AIRMET information and special air-reports relevant to the flight, unless these have already been the subject of a SIGMET message; d) information on wind and temperature aloft; e) advisory information on volcanic ash and tropical cyclones; and f) other meteorological information in alphanumeric or graphic form, as agreed between the meteorological authorities and the relevant operator.
Guidance on the presentation of graphical information in the cockpit is contained in ICAO Doc 8896.
APPENDIX 9 TECHNICAL SPECIFICATIONS RELATING TO INFORMATION FOR AIR TRAFFIC SERVICES, SEARCH AND RESCUE SERVICES, AND AERONAUTICAL INFORMATION SERVICES 1. INFORMATION TO BE PROVIDED TO AIR TRAFFIC SERVICES UNITS 1.1 List of information for the aerodrome control tower The aerodrome meteorological office associated with the aerodrome control tower shall provide the latter with the following meteorological information, as necessary:
- a)routine local reports (informes locales ordinarios), special local reports (informes locales especiales), METAR, SPECI, TAF, trend-type forecasts (pronósticos de tipo tendencia), and amendments thereto, for the aerodrome concerned; b) SIGMET and AIRMET information, wind shear advisories and alerts, and aerodrome warnings; c) any other locally agreed meteorological information, such as surface wind forecasts, for determining possible runway changes; and d) information received on a volcanic ash cloud, for which a SIGMET message has not yet been issued, as agreed between the meteorological and ATS authorities concerned; and e) information received on pre-eruption volcanic activity or a volcanic eruption, as agreed between the meteorological authorities and the competent ATS authorities.
1.2 List of information for the approach control unit The aerodrome meteorological office associated with the approach control unit shall provide the latter with the following meteorological information, as necessary:
- a)routine local reports (informes locales ordinarios), special local reports (informes locales especiales), METAR, SPECI, TAF, and trend-type forecasts (pronósticos de tipo tendencia) and amendments thereto, for the aerodrome or aerodromes for which the approach control unit is responsible; b) SIGMET and AIRMET information, wind shear advisories and alerts, and special air-reports appropriate for the airspace for which the approach control unit is responsible, and aerodrome warnings; c) any other locally agreed meteorological information; d) information received on a volcanic ash cloud, for which a SIGMET message has not yet been issued, as agreed between the meteorological and ATS authorities concerned; and e) information received on pre-eruption volcanic activity or a volcanic eruption, as agreed between the meteorological authorities and the competent ATS authorities.
1.3 List of information for the flight information centre and area control centre The associated meteorological watch office shall provide, as necessary, the following meteorological information to a flight information centre or an area control centre:
- a)METAR and SPECI, including current pressure data for aerodromes and other locations, TAF and trend-type forecasts (pronósticos de tipo tendencia) and their amendments, covering the flight information region (FIR) or the control area (CTA) and, if so 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 wind and temperature aloft and significant weather phenomena en route and their amendments, particularly those likely to preclude operations in accordance with visual flight rules, SIGMET and AIRMET information, and special air-reports appropriate 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 needed by the FIC or ACC to meet requests from aircraft in flight; if the requested information is not available at the associated meteorological watch office (MWO), it shall request assistance from another meteorological office to provide it; d) information received on a volcanic ash cloud, for which a SIGMET message has not yet been issued, as agreed between the meteorological and ATS authorities concerned; e) information received on the release of radioactive materials into the atmosphere, as agreed between the meteorological authority and the ATS authority concerned; f) information on tropical cyclone advisories issued by a tropical cyclone advisory centre in this area of responsibility; g) information on volcanic ash advisories issued by a volcanic ash advisory centre in this area of responsibility; and h) information received on pre-eruption volcanic activity or a volcanic eruption, as agreed between the meteorological and competent ATS authorities.
1.4 Supply of information to aeronautical telecommunication stations When necessary for flight information purposes, current meteorological reports and forecasts shall be provided to designated aeronautical telecommunication stations. A copy of such information shall be sent to the FIC or the ACC, if required.
1.5 Format of the information 1.5.1 Routine local reports (informes locales ordinarios), special local reports (informes locales especiales), METAR, SPECI, TAF, and trend-type forecasts (pronósticos de tipo tendencia), SIGMET and AIRMET information, forecasts of wind and temperature aloft, and amendments thereto shall be provided 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 in digital form relating to grid points are made available to air traffic services units for use in air traffic services computers, the content, format, and arrangements for their transmission shall be as agreed between the meteorological authority and the competent ATS authority.
Normally, the data should be provided as soon as possible after the processing of the forecasts is completed.
2. INFORMATION TO BE PROVIDED TO SEARCH AND RESCUE SERVICES UNITS 2.1 List of information The information to be provided to rescue coordination centres shall include the meteorological conditions that existed at the last known position of the missing aircraft and along the intended route of that aircraft, with particular reference to:
- a)significant weather phenomena en route; b) amount and type of clouds, particularly cumulonimbus; indications of base and top heights; c) visibility and phenomena reducing visibility; d) surface wind and wind aloft; e) state of the ground; particularly, any snow-covered or flooded ground; f) sea surface temperature, sea state, ice cover, if any, and ocean currents, if pertinent to the search area; and g) sea-level pressure data.
2.2 Information to be provided on request 2.2.1 At the request of the rescue coordination centre, the designated aerodrome meteorological office or MWO shall arrange to obtain details of the flight documentation that was provided to the missing aircraft, together with any forecast amendments that were transmitted to the aircraft in flight.
2.2.2 To facilitate search and rescue operations, the designated aerodrome meteorological office or MWO shall provide, upon request:
- a)complete and detailed information about current and expected meteorological conditions in the search area; and b) current and expected en-route conditions relating to the flights of the search aircraft from and back to the aerodrome from which the search operations are being conducted.
2.2.3 At the request of the rescue coordination centre, the designated aerodrome meteorological office or meteorological watch office shall provide, or arrange for the provision of, meteorological information needed by ships participating in search and rescue operations in connection with such activities.
3. INFORMATION TO BE PROVIDED TO AERONAUTICAL INFORMATION SERVICES UNITS 3.1 List of information If necessary, the following data shall be provided to aeronautical information services units:
- a)information on meteorological services for international air navigation to be included in the corresponding aeronautical information publications.
Details on this information are given in the Procedures for Air Navigation Services - Aeronautical Information Management (PANS-AIM, ICAO 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, especially in relation to:
- 1)the establishment, elimination, or significant changes in the operation of aeronautical meteorological services. These data must be provided to the aeronautical information services unit sufficiently in advance of their effective date so that a NOTAM can be issued in accordance with the provisions of RAC-15 Aeronautical Information Services, Decree No.42396-MOPT, of April 7, 2020, La Gaceta No.157 of June 30, 2020, in RAC-15.0345; 2) the occurrence of volcanic activity; and The necessary information is indicated in Subpart C, RAC-03.085 and in Subpart D, RAC-03.335.
- 3)information received regarding the release of radioactive materials into the atmosphere, as agreed between the meteorological authority and the competent civil aviation authorities concerned; and In Subpart C, RAC-03.095 g) of this regulation, the specific information is provided.
- c)the information necessary for the preparation of aeronautical information circulars, especially in relation to:
- 1)significant planned changes to available aeronautical meteorological procedures, services, and facilities; and 2) the effects of certain meteorological phenomena on aircraft operations.
APPENDIX 10 TECHNICAL SPECIFICATIONS RELATING TO COMMUNICATIONS NEEDS AND USE 1. SPECIFIC REQUIREMENTS FOR COMMUNICATIONS 1.1 Required transit times for meteorological information The transit times for AFTN messages and bulletins containing meteorological information for operations must be less than five minutes, unless determined to be shorter by regional air navigation agreement.
1.2 Gridded data for ATS and operators 1.2.1 When altitude data relating to grid points are provided in digital form for use in air traffic services computers, the arrangements for their transmission must be as agreed between the meteorological authorities and the competent ATS authority.
1.2.2 When altitude data relating to grid points in digital form are made available to operators for computer-based flight planning, the arrangements for their transmission must be as agreed between the world area forecast centre concerned, the meteorological authority, and the operators concerned.
2. USE OF AERONAUTICAL FIXED SERVICE AND PUBLIC INTERNET COMMUNICATIONS 2.1 Meteorological bulletins in alphanumeric format 2.1.1 Composition of bulletins Whenever possible, the exchange of meteorological information for operations must be carried out by means of consolidated bulletins of similar types of meteorological information.
2.1.2 Bulletin filing times Meteorological bulletins required for regular transmissions must be filed regularly and at scheduled times. METARs must be filed for transmission no more than five minutes after the time of observation. TAFs must be filed for transmission no more than one hour before the start of their validity period.
2.1.3 Bulletin headings Meteorological bulletins containing meteorological information for operations and intended for transmission via the aeronautical fixed service or the public Internet must contain a heading consisting of:
- a)a four-letter and two-number identifier; b) the ICAO four-letter location indicator corresponding to the geographic location of the meteorological office issuing or compiling the meteorological bulletin; c) a day-time group; and d) if necessary, a three-letter indicator.
The detailed specifications for the format and content of the heading appear in the Manual on the Global Telecommunication System (WMO No. 386) and are reproduced in the Manual of Aeronautical Meteorological Methods (Doc 8896).
ICAO location indicators are listed in Location Indicators (Doc 7910).
2.1.4 Structure of bulletins Meteorological bulletins containing meteorological information for operations and intended for transmission via the AFTN shall be placed in the text part of the AFTN message format.
2.2 Information produced by the world area forecast system (WAFS) 2.2.1 Telecommunications to provide information produced by the WAFS The telecommunications facilities used to provide the information produced by the WAFS are the aeronautical fixed service or the public Internet.
2.2.2 Quality requirements for charts In cases where information produced by the WAFS is disseminated in chart form, the charts received must be of a quality that allows sufficiently legible reproduction for flight planning and documentation. The received charts must be legible over 95% of their surface area.
2.2.3 Quality requirements for transmissions Transmissions must be made in such a way as to ensure that their interruption does not exceed 10 minutes during a 6-hour period.
2.2.4 Heading of bulletins containing information produced by the WAFS Meteorological bulletins containing information produced by the WAFS in digital form to be transmitted via the aeronautical fixed service or the public Internet must include a heading, as indicated 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 compatible with the provisions of this regulation.
3.1.2 The content and format of special aircraft observations (aeronotificaciones) transmitted by aircraft shall be compatible with the provisions of Subpart E of this RAC and the Procedures for Air Navigation Services — Air Traffic Management (PANS-ATM, ICAO Doc. 4444), Appendix 1.
3.2 Content and format of meteorological bulletins The essential content of meteorological bulletins transmitted by means of the aeronautical mobile service shall not be modified from that of the original message in the bulletin.
4. USE OF THE AERONAUTICAL DATA LINK SERVICE — D-VOLMET 4.1 Detailed content of meteorological information available for D-VOLMET 4.1.1 The aerodromes for which METARs, SPECIs, and TAFs are to be delivered for transmission 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 delivered for transmission to aircraft in flight are determined by regional air navigation agreement.
4.2 Criteria relating to the information required for D-VOLMET 4.2.1 The most recent valid METARs, SPECIs, TAFs, and SIGMETs, and AIRMETs must be used for transmission to aircraft in flight.
4.2.2 The TAFs included in the D-VOLMET data link service must be amended as necessary to ensure that, when available for transmission to aircraft in flight, they reflect the most recent opinion of the relevant aerodrome meteorological office.
4.2.3 If no valid SIGMET message exists for an FIR in the D-VOLMET data link service, the indication "NIL SIGMET" must be included.
4.3 Format of the information required for D-VOLMET The content and format of the reports, forecasts, and SIGMET and AIRMET information included in the D-VOLMET service conform to the provisions of this regulation.
5. USE OF THE AERONAUTICAL BROADCAST SERVICE — VOLMET BROADCASTS 5.1 Detailed content of the meteorological information to be included in VOLMET broadcasts 5.1.1 The aerodromes for which METARs, SPECIs, and TAFs are to be included in VOLMET broadcasts, the order in which they are to be transmitted, and the broadcast times are determined by regional air navigation agreement.
5.1.2 The flight information regions for which SIGMET messages are to be included in regular VOLMET broadcasts are determined by regional air navigation agreement. When this is done, the SIGMET message is transmitted at the beginning of the broadcast or of a five-minute time slot.
5.2 Criteria relating to the information to be included in VOLMET broadcasts 5.2.1 If an aerodrome report has not arrived in time for its broadcast, the latest available report must be included in the broadcast, together with the time of observation.
5.2.2 The TAFs included in regular VOLMET broadcasts must be amended, as necessary, to ensure that a forecast, when transmitted, represents the most recent opinion of the aerodrome meteorological office concerned.
5.2.3 When SIGMET messages are included in regular VOLMET broadcasts, the indication "NIL SIGMET" must be transmitted if no valid SIGMET message exists for the flight information regions concerned.
5.3 Format of the information to be included in VOLMET broadcasts 5.3.1 The content and format of the reports, forecasts, and SIGMET information included in VOLMET broadcasts conform to the provisions of this regulation.
5.3.2 Standardized radiotelephony phraseology must be used in VOLMET broadcasts.
Guidance on the standardized radiotelephony phraseology for use in VOLMET broadcasts is provided in Appendix 1 of the Manual on Coordination between Air Traffic Services, Aeronautical Information Services and Aeronautical Meteorological Services (ICAO Doc. 9377).
ATTACHMENT A OPERATIONALLY DESIRABLE ACCURACY OF MEASUREMENT OR OBSERVATION ATTACHMENT B OPERATIONALLY DESIRABLE ACCURACY OF FORECASTS ATTACHMENT C SELECTION OF CRITERIA APPLICABLE TO AERODROME REPORTS ATTACHMENT D CONVERSION OF INSTRUMENTAL READINGS TO VALUES OF RUNWAY VISUAL RANGE AND VISIBILITY 1. The conversion of instrumental readings to values of runway visual range and visibility is based on Koschmieder's law or Allard's law, depending on whether the pilot is expected to derive primary visual guidance from the runway and its markings, or from runway lights. In order to standardize the assessment of runway visual range, this attachment provides guidance on the use and application of the main conversion factors to be used in these calculations.
2. In Koschmieder's law, one of the factors to be considered is the pilot's contrast threshold. The agreed constant to be used for this purpose 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 that depends on the background luminance. The agreed relationship to be used in instrumental systems with continuous adjustment of the illumination threshold by means of a background luminance sensor is indicated by the curve in Figure D-1. It is preferable to use a continuous function approximating the step function presented in Figure D-1, for its greater accuracy, rather than the step relationship described in paragraph 4.
4. In instrumental systems without continuous adjustment of the illumination threshold, it is convenient to use four illumination threshold values, set at equal intervals, with the corresponding background luminance ranges that have been agreed upon, although accuracy will decrease. The four values are indicated in Figure D-1 in the form of a step function and, for clarity, are detailed in Table D-1.
The Manual on the Observation and Reporting of Runway Visual Range (ICAO Doc. 9328) contains information and guidance texts on the runway lights to be used for calculating runway visual range.
In accordance with the definition of visibility in the aeronautical sense, the intensity of the lights to be used for the assessment of visibility is in the vicinity of 1 000 cd.
2.1 GENERAL JOINT ADVISORY CIRCULARS (CCA) 2.1.1 This section contains the Joint Advisory Circulars (Circulares Conjuntas de Asesoramiento, CCA) that have been approved for inclusion in RAC 03.
2.1.2 If a specific paragraph does not have a CCA, it is considered that said paragraph does not require them.
2.2 PRESENTATION 2.2.1 The numbers preceded by the abbreviations CCA indicate the number of the paragraph of RAC 03 to which they refer.
2.2.2 The abbreviation is defined as follows: Joint Advisory Circulars (Circulares Conjuntas de Asesoramiento, CCA): Text associated with the requirements of a RAC, to qualify and provide guidance for its application. It contains explanations, interpretations, and/or acceptable methods of compliance.
SUBPART A DEFINITIONS, APPLICATION, AND AVAILABILITY Has no associated CCA.
SUBPART B GENERAL PROVISIONS CCA RAC-03.004 Operational Directives (See RAC-03.004) Operational Directives contain:
- 1)The Reason for their Issuance; 2) Their scope of application and duration; 3) Action required from service providers.
CCA RAC 03.005 General Provisions (See RAC 03.005) It is recognized that the provisions of this RAC relating to meteorological information assume that, in accordance with Article 28 of the Convention on International Civil Aviation, it is the obligation of the Costa Rican State to provide such information, and that the responsibility for the use made of it lies with the user.
Although the Convention assigns to the State of Registry certain functions that said State has the authority to perform, or is obliged to perform, as the case may be, the Assembly recognized, in Resolution A23-13, that the State of Registry might not be able to properly fulfil its obligations in cases where aircraft have been leased, chartered, or interchanged — especially without crew — by an operator of another State, and that the Convention might not adequately specify the rights and obligations of the State of an Operator in such cases, until Article 83 bis of the Convention enters into force. Consequently, the Council urged that, if in the above-mentioned cases the State of Registry finds itself unable to adequately perform the functions assigned to it by the Convention, it delegate to the State of the Operator, subject to the acceptance of the latter State, those functions of the State of Registry that may be more adequately performed by the State of the Operator. It was understood that, until Article 83 bis of the Convention enters into force, this measure would only be adopted for practical reasons and would not affect the provisions of the Chicago Convention prescribing the obligations of the State of Registry, nor third States. Nevertheless, with the entry into force of Article 83 bis of the Chicago Convention on June 20, 1997, such transfer arrangements shall have effect with respect to those contracting States that have ratified the corresponding Protocol (ICAO Doc 9318), once the conditions of Article 83 bis have been fulfilled.
In the case of international operations conducted collectively with aircraft not all registered in the same contracting State, nothing in this part prevents the States concerned from entering into an agreement for the joint exercise of the functions attributed to the State of Registry by the provisions of this RAC.
For the purposes of this RAC, a contracting State is considered to be a State that has consented to be bound by the compliance with the Convention on International Civil Aviation of 1944.
CCA RAC-03.015 Meteorological Authority (See RAC-03.015) The Aeronautical Information Publication of Costa Rica (AIP) includes details on the Meteorological Authority thus designated, in accordance with the PANS-AIM, ICAO Doc. 10066, Appendix 2, GEN 1.1.
The Procedures for Air Navigation Services — Aeronautical Information Management (PANS-AIM, ICAO Doc. 10066, Appendix 2) contain detailed specifications on the presentation and content of the aeronautical information publication.
CCA RAC 03.020 Meteorological Authority Requirements (See RAC 03.020) The aeronautical meteorological service provider must develop the training plans and programmes for its personnel, so that, as a minimum, they comply with the Technical Regulations (WMO No. 49), Volume I — General Meteorological Standards and Recommended Practices, Part V — Qualifications and Competencies of Personnel Involved in the Provision of Meteorological, Hydrological, and/or Climatological Services, Part VI — Education and Professional Training of Meteorological Personnel, and Appendix A — Basic Instructional Packages.
These plans and programs must contain the details of Initial training, Specialized training, On-the-job Evaluations, and Updates.
The aeronautical meteorological service provider must maintain individual records of the training received by its technical personnel; these records can be kept in printed or digital format, and must be files independent of employment records or files.
The aeronautical meteorological service provider must request the review and approval of the Civil Aviation Authority for the manuals, procedures, and agreements necessary to comply with the requirements of this regulation.
CCA RAC-03.225 Surface Wind (See RAC-03.225) The aeronautical meteorological service provider, in coordination with the Aeronautical Authority, must ensure that the wind sensors used for the ordinary local reports are properly sited to provide the best possible indication of conditions along the runway or in the touchdown zone. To carry out the analysis of the best siting, it must use the guidance provided in ICAO Doc. 8896, Appendix 2, and in Appendix 3 of this RAC. And, to the extent possible for each site, comply with the distances indicated to ensure compliance regarding siting as indicated in RAC-14 Aerodrome Design and Construction, Volume 1, Decreto No.42395-MOPT, Alcance No.194 to La Gaceta No.182 of July 25, 2020, and the recommendations of WMO document 488 on Observing Systems.
CCA RAC 03.035 Quality Management of Meteorological Information (See RAC 03.035) The ISO 9000 series quality assurance standards provide a basic framework for the development of a quality assurance program. The details of a successful program must be formulated by each State and in most cases are unique to the State's organization. Guidance on the establishment and implementation of a quality system is provided in WMO document WMO-No. 1100 "Guide to the Implementation of Quality Management Systems for National Meteorological and Hydrological Services and Other Relevant Service Providers." CCA RAC 03.040 International Quality Assurance Standards (See RAC-03.040) The Instituto Meteorológico Nacional must include in its budget the Certification, as well as the entire budget necessary for the proper implementation and maintenance of its Quality Management System (QMS). The IMN may certify this QMS with an approved organization, in accordance with the WMO document WMO-No. 1100 "Guide to the Implementation of Quality Management Systems for National Meteorological and Hydrological Services and Other Relevant Service Providers" and national regulations.
The requirements for geographic and spatial coverage, format and content, time and frequency of issuance, and validity period of the meteorological information provided to aeronautical users must correspond to those indicated in Subpart C to Subpart J and Appendices 2, 3, 5, 6, 7, 8, and 9 of this RAC, as well as in regional air navigation plans when applicable.
The accuracy requirements for measurement and observation, and the accuracy of forecasts must correspond to those presented in Attachments A and B of this RAC.
CCA RAC-03.045 Information Exchange (See RAC-03.045) The requirements relating to the exchange of operational meteorological information are presented in Subpart K and in Appendix 10 of this RAC.
CCA RAC-03.050 Quality Audit (See RAC-03.050) Attachment A of this RAC provides guidance on the operationally desirable accuracy of measurement or observation. 2.2.8.
Attachment B of this RAC provides guidance on the operationally desirable accuracy of forecasts.
Due to the variability of meteorological elements in space and time, the limitations of observation techniques, and the limitations imposed by the definitions of some of the elements, the recipient of the report shall understand that the specific value of some of the elements given in a report represents the best approximation to the actual conditions at the time of observation.
Due to the variability of meteorological elements in space and time, the limitations of forecasting techniques, and the limitations imposed by the definitions of some of the elements, the recipient of the report shall understand that the specified value of any of the elements given in a forecast represents the most probable value that said element may have during the forecast period.
Similarly, when the time of occurrence or change of an element is given in a forecast, this time shall be understood as the most probable.
CCA RAC-03.055 Information Format (See RAC-03.055) The aeronautical meteorological service provider must rely on the Human Factors Training Manual, ICAO Doc. 9683.
CCA RAC-03.085 Functions of Aerodrome Meteorological Offices (See RAC-03.085) Each aerodrome meteorological office may fulfil several or all of these functions, but they must be defined in the letters of agreement between the meteorological service provider and ATS according to the requirements, personnel capabilities, and availability of meteorological equipment at each aerodrome.
Regarding Volcanic Ash Advisory information, what is indicated in the Technical Specifications of Appendix 2 of this RAC, 3.1 Volcanic ash advisory information, must be used as applicable.
SUBPART C WORLDWIDE SYSTEMS, SUPPORT CENTRES, AND METEOROLOGICAL OFFICES CCA.RAC-03.100 Coordination of the meteorological service provider with the volcanic ash advisory centre (VAAC) (See RAC-03.100) The template used for special aircraft observations (aeronotificaciones especiales) uplinked to aircraft in flight is provided in Appendix 6 of this RAC, Table A6-1B.
CCA RAC-03.105 State Volcano Observatories (See RAC-03.105) ICAO Doc. 9766 provides guidance on active or potentially active volcanoes.
The information required to be sent by the volcano observatories of the Costa Rican State to their associated area control centres (ACC)/flight information centres (FIC), meteorological watch office (MWO), and VAAC must be constituted as indicated in Appendix 2 of this RAC, point 4. 4.1 Information from State volcano observatories and Table A2-1. Template for volcanic ash advisory message.
CCA RAC-03.120 Tropical Cyclone Advisory Centres (See RAC-03.120) The tropical cyclone advisory information to be issued is indicated in Appendix 2 of this RAC, point 5. 5.1 and Table A2-2. Template for tropical cyclone advisory message.
CCA RAC-03.125 Space Weather Centres (See RAC-03.125) The Manual on Space Weather Information in Support of International Air Navigation, ICAO Doc. 10100, provides guidance on the provision of such information, which includes providers, designated by ICAO, of space weather advisory information.
See details of the Space Weather Centres information in Appendix 2 of this RAC, point 6. 6.1 and Table A2-3. Template for advisory message on space weather conditions.
The meteorological service provider must establish letters of agreement or establish an Operational Agreement with the communications service provider of the Costa Rican State (Corporación Centroamericana de Servicios de Navegación Aérea, COCESNA), to ensure it receives the information described in RAC-03.125.
SUBPART D METEOROLOGICAL OBSERVATIONS AND REPORTS CCA RAC-03.145 Inspections, Maintenance, and Quality (See RAC-03.145) The Manual on Automatic Meteorological Observing Systems at Aerodromes (ICAO Doc. 9837) provides guidance on the inspection of aeronautical meteorological stations, including the frequency of inspections. In addition, the meteorological service provider must consider the equipment manufacturer's maintenance and calibration recommendations.
CCA RAC-03.150 Automatic Meteorological Equipment on Runways Intended for Category II and III Instrument Approach and Landing Operations (See RAC-03.150) The categories of precision approach and landing operations are defined in ICAO Annex 6, Operation of Aircraft, Part I. Guidance on the application of human factors principles can be found in the Human Factors Training Manual (ICAO Doc. 9683).
There may be a meteorological equipment provider that the Aeronautical Authority and the aeronautical meteorological service provider, if warranted, may contract for the purposes of installation, operation, and maintenance of the automatic equipment at stations at aerodromes with runways intended for Category II and III instrument approach and landing operations. For this equipment, the meteorological service provider remains the custodian of the data and the respective quality controls for the data, as well as what corresponds according to RAC-03.130, RAC-03.140, and RAC-03.145.
CCA RAC-03.155 Automatic Meteorological Equipment on Runways Intended for Category I Instrument Approach and Landing Operations (See RAC-03.155) The categories of precision approach and landing operations are defined in ICAO Annex 6, Part I.
Guidance on the application of human factors principles can be found in the Human Factors Training Manual (ICAO Doc. 9683).
CCA RAC-03.170 Accuracy of the Report (See RAC-03.170) Due to the variability of meteorological elements in space and time, the limitations of observation techniques, and the limitations imposed by the definitions of some of the elements, the aeronautical meteorological service provider must ensure that the recipient of the report understands that the specific value of some of the elements given in a report represents the best approximation to the actual conditions at the time of observation.
CCA RAC-03.175 Agreements between the Meteorological Authority and Air Traffic Authorities (See RAC-03.175) The Manual on Coordination between Air Traffic Services, Aeronautical Information Services and Aeronautical Meteorological Services (ICAO Doc. 9377) provides guidance on the subject of coordination between air traffic services and aeronautical meteorological services.
CCA RAC-03.185 Routine Reports (See RAC-03.185) The meteorological information used in ATIS (ATIS-voice and D-ATIS) shall be extracted from the routine local report, in accordance with RAC ATS Air Traffic Services, Decreto No. 42397-MOPT, Alcance No.161 to La Gaceta No.157 of June 30, 2020, at point RAC-ATS.310 f) 1) VII.
Routine local reports shall be issued in abbreviated plain language, in accordance with the Technical Specifications Relating to Meteorological Observations and Reports indicated in Appendix 3 of this RAC and in accordance with the template in Table A3-1.
CCA RAC-03.190 Special Reports for Aerodromes Not Operating 24 Hours (See RAC-03.190) The location indicators cited in b) and their meanings are published in Location Indicators (ICAO Doc. 7910).
CCA RAC-03.200 Special Observation Reports (See RAC-03.200) The meteorological information used in ATIS (ATIS-voice and D-ATIS) shall be extracted from the special local report, in accordance with RAC ATS Air Traffic Services, Decreto No. 42397-MOPT, Alcance No.161 to La Gaceta No.157 of June 30, 2020, at point RAC-ATS.310 f) 1) VII.
Special local reports are issued in abbreviated plain language, in accordance with the Technical Specifications Relating to Meteorological Observations and Reports indicated in Appendix 3 and in accordance with the template in Table A3-2 and disseminated in the METAR and SPECI code forms prescribed by the WMO.
CCA RAC-03.210 Content of Reports (See RAC-03.210) The location indicators cited in b) and their meanings are published in Location Indicators (ICAO Doc. 7910).
Special local reports are issued in abbreviated plain language, in accordance with the Technical Specifications Relating to Meteorological Observations and Reports indicated in Appendix 3 of this RAC.
CCA RAC-03.225 Surface Wind (See RAC-03.225) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.230 Surface wind (See RAC-03.230) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in point 4.1 of Appendix 3 of this RAC.
CCA RAC-03.235 Surface wind (See RAC-03.235) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in point 4.1 of Appendix 3 of this RAC.
CCA RAC-03.240 Unit of measurement of visibility (See RAC-03.240) Attachment D of this RAC provides guidance on the conversion of instrument readings to visibility values.
See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.240 Runway visual range (See RAC-03.240) The Manual of Runway Visual Range Observing and Reporting Practices (ICAO Doc. 9328) contains guidance relating to runway visual range.
See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.245 Reports for departing and arriving aircraft (See RAC-03.245) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.250 METAR and SPECI observation (See RAC-03.250) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.255 Runway visual range (See RAC-03.255) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.260 Runways for which runway visual range shall be assessed (See RAC-03.260) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.265 Notification and assessments of runway visual range (See RAC-03.265) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.275 Content of the present weather report (See RAC-03.275) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.305 Units of measurement for air temperature and dew point (See RAC-03.305) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.310 Atmospheric pressure (See RAC-03.310) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.315 Supplementary information (See CCA RAC-03.315) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
CCA RAC-03.320 METAR and SPECI reporting from automatic observation systems (See RAC-03.320) The Manual on Automatic Meteorological Observing Systems at Aerodromes (ICAO Doc. 9837) provides guidance on the use of such systems.
They are issued in accordance with the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
The issuance of automated METAR and SPECI without an observer to verify the present weather and cloudiness results is used only for extreme emergency situations where the observer cannot be available for a short period due to the severity of the situation; this must be done by prior agreement with the Aeronautical Authority and must be agreed upon with ATC in the letter of agreement.
CCA RAC-03.330 Form of notification of meteorological reports from automatic observation systems (See RAC-03.330) See the Technical Specifications Relating to Meteorological Observations and Reports set forth in Appendix 3 of this RAC.
SUBPART E AIRCRAFT OBSERVATIONS AND REPORTS CCA RAC-03.340 Obligations of States (See RAC-03-340) The Technical Specifications Relating to Aircraft Observations and Reports corresponding to Subpart E of this RAC are set forth in Appendix 4 of this RAC.
CCA RAC-03.375 Special aircraft observations (See RAC-03.375) Special aircraft observations are issued in accordance with the Technical Specifications Relating to Aircraft Observations and Reports corresponding to Subpart E of this RAC, set forth in Appendix 4 of this RAC, and in accordance with the template in Table A4-1.
SUBPART F FORECASTS CCA RAC-03.410 Aerodrome forecasts (See RAC-03.410) Appendix 5 of this RAC presents the Technical Specifications and the detailed criteria corresponding to Subpart F of this RAC.
CCA RAC-03.420 Aerodrome forecasts (See RAC-03.420) The aerodromes for which aerodrome forecasts must be prepared and the period of validity of these forecasts are listed in the corresponding facilities and services document (FASID).
Every TAF must be issued with the Technical Specifications Relating to Forecasts set forth in Appendix 5 and in accordance with the template in Table A5-1, both of this RAC.
CCA RAC-03.430 Content of TAFs (See RAC-03.430) Every TAF must be issued with the Technical Specifications Relating to Forecasts set forth in Appendix 5 and in accordance with the template in Table A4-1, both of this RAC.
CCA RAC-03.435 Study and changes to TAF Forecasts (See RAC-03.435) Chapter 3 of the Manual of Aeronautical Meteorological Methods (ICAO Doc. 8896) provides guidance on methods for subjecting the TAF to a continuous review process.
SUBPART G SIGMET AND AIRMET INFORMATION, AERODROME WARNINGS AND WIND SHEAR WARNINGS AND ALERTS CCA RAC-03.495 SIGMET information (See RAC-03.495) AIRMET reports are issued according to the Technical Specifications Relating to SIGMET Reports set forth in Appendix 6 of this RAC.
CCA RAC-03.510 AIRMET reports (See RAC-03.510) AIRMET reports are issued according to the Technical Specifications Relating to AIRMET Reports set forth in Appendix 6 of this RAC.
CCA RAC-03.520 Aerodrome warnings (See RAC-03.520) Wind shear warnings must be issued according to the Technical Specifications Relating to Aerodrome Warning Information set forth in Appendix 6 of this RAC.
CCA RAC-03.530 Wind shear warning and alerts (See RAC-03.530) The Manual on Low-Level Wind Shear (ICAO Doc. 9817) provides guidance on the referenced subject. It is expected that wind shear alerts will complement the warnings in question, which, in combination, are intended to improve situational awareness regarding wind shear.
Wind shear warnings must be issued according to the Technical Specifications Relating to Wind Shear Warning Information set forth in Appendix 6 of this RAC.
SUBPART H AERONAUTICAL CLIMATOLOGICAL INFORMATION CCA RAC-03.545 General provisions (See RAC-03.545) All aeronautical climatological information must be issued at a minimum according to the Technical Specifications Relating to Aeronautical Climatological Information set forth in Appendix 7 of this RAC.
Appendix 7 of this RAC presents the technical specifications and the detailed criteria corresponding to Subpart H of this regulation.
When it is not possible to meet the needs for aeronautical climatological information at the national level, the collection, processing, and storage of observational data may be carried out through computerized facilities available for international use, and the responsibility for preparing the necessary aeronautical climatological information may be delegated as agreed between the meteorological authorities concerned.
The measurement characteristics and data for the siting of new aerodromes must include data on wind magnitude and direction, as well as air temperature, from at least an hourly record; the information must be analyzed by a meteorology expert; this information must have a minimum data loss of 10%; the data shall correspond to nearby reference stations for the initial design phases of new aerodromes, with the objective of having at least 5 years of estimated information on wind and temperature variables. Whereas for the operational start-up phase of the new aerodrome, it must have a 5-year record of said variables measured continuously or with a minimum data loss of 10% on site. The stations must meet the requirements established in this regulation regarding measurement certainty and location. They must also receive the treatments indicated regarding maintenance, data quality control, and calibrations set forth in this regulation for all types of meteorological measurements for aeronautical purposes.
For private aerodromes, private-use aerodromes open to the public, landing fields, and heliports, the details of the climatological data are those set forth by the DGAC in its registration procedures.
CCA RAC-03.550 General provisions (See RAC-03.550) The climatological information required for aerodrome planning purposes is set forth in RAC-14 Aerodrome Design and Construction, Volume 1, Decree No. 42395-MOPT, Scope No. 194 to La Gaceta No. 182 of July 25, 2020, in point RAC 14.201 Runways 3.1 (d), and in the same document, also see Attachment A. General Guidance Text that Complements the Provisions of RAC 14 and RAC 139.
SUBPART I SERVICE FOR OPERATORS AND FLIGHT CREW MEMBERS CCA RAC-03.580 Responsibility for the control and quality management of meteorological information (See RAC-03.580) Appendix 8 of this RAC presents the Technical Specifications and the detailed criteria corresponding to Subpart I of this regulation.
CCA RAC-03.590 Meteorological information to operators and flight crew members (See RAC-03.590) The charts generated from digital forecasts provided by the WAFCs will be available, as required by operators, for fixed coverage areas, as illustrated in Appendix 8, Figures A8-1, A8-2 and A8-3 of this RAC.
Humidity forecasts at altitude and geopotential altitude of flight levels are used only in automatic flight planning and do not need to be displayed.
It is expected to process and, if necessary, display forecasts of cumulonimbus clouds, icing, and turbulence, according to specific thresholds based on user operations.
Appendix 1 of this RAC presents the specifications relating to flight documentation (including model charts and forms).
CCA RAC-03.600 Forecasts originated by WAFCs (See RAC-03.600) The charts generated from digital forecasts provided by the WAFCs will be available, as required by operators, for fixed coverage areas, as illustrated in Appendix 8, Figures A8-1, A8-2 and A8-3 of this RAC.
CCA RAC-03.605 Forecasts in cartographic form (See RAC-03.605) The specified flight levels: in Appendix 2 of this RAC, point 1.2.2 a).
When the forecasts of SIGWX phenomena listed in RAC-03.590 a) 6) are provided in cartographic form, they shall constitute fixed-time prognostic charts for an atmospheric layer bounded by the flight levels specified in Appendix 2 of this RAC, point 1.3.2, and in Appendix 5 of this RAC, point 4.3.2.
CCA RAC-03.625 Verbal briefing, consultation, and display of information (See CCA RAC-03.625) The requirements relating to the use of automated pre-flight information systems for providing verbal briefings, consultation, and display are set forth in RAC-03.665 to RAC-03.675.
The information displayed must be readily accessible to flight crew members or other flight operations personnel.
For the use and notification of information produced by the world area forecast system (WAFS), see the Technical Specifications in Appendix 2 of this RAC.
CCA RAC-03.670 Common access points to automated information systems (See RAC-03.670) The meteorological information and the information from the aeronautical information services concerned are specified in 03.580 to 03.590, and in Appendix 8 of this RAC, and in the Procedures for Air Navigation Services — Aeronautical Information Management (PANS-AIM, ICAO Doc. 10066), 5.5, respectively.
CCA RAC-03.675 Common access points to automated information systems (See RAC-03.675) The responsibilities corresponding to the information from aeronautical information services and to the quality assurance of the information are presented in RAC 15.045.
SUBPART J INFORMATION FOR AIR TRAFFIC SERVICES, SEARCH AND RESCUE SERVICES, AND AERONAUTICAL INFORMATION SERVICES CCA RAC-03.685 Information for air traffic services units (See RAC-03.685) Appendix 9 of this RAC presents the Technical Specifications and the detailed criteria corresponding to Subpart J of this regulation.
SUBPART K REQUIREMENTS AND USE OF COMMUNICATIONS CCA RAC-03.715 Requirements for communications for air traffic services units (See RAC-03.715) Appendix 10 of this RAC presents the technical specifications and the detailed criteria corresponding to Subpart K of this regulation.
It is recognized that it is for each Contracting State to decide on its internal organization and responsibility for implementing the telecommunications facilities mentioned in Subpart K of this RAC.
CCA RAC-03.725 Requirements for communications for world area forecast centres (See RAC-03.725) See the Technical Specifications Relating to World Systems, Support Centres, and Meteorological Offices, in Appendix 2 of this RAC.
CCA RAC-03.755 Operation of the exchange of meteorological information (See RAC-03.755) In support of the global exchanges of meteorological information for operations, the Internet-based services of the aeronautical fixed service are used, operated by the world area forecast centres, which provide global coverage. Guidance on the use of public Internet for aeronautical applications (ICAO Doc. 9855) provides guidelines on meteorological information for operations where time is not critical and the relevant aspects of the public Internet.
In the event that the aeronautical fixed system fails, meteorological information may be consulted from the aeronautical digital data system centres, particularly regarding METAR and TAF; these systems or web pages must be duly established in the letters of agreement between the ATC units and the aeronautical meteorological service provider, and both parties must also establish the processes under which these alternative meteorological information exchange systems will be used.
CCA RAC-03.755 Use of aeronautical fixed service communications and the public Internet - Meteorological bulletins (See RAC-03.755) In support of the global exchanges of meteorological information for operations, the Internet-based services of the aeronautical fixed service are used, operated by the world area forecast centres, which provide global coverage. The Guidance on the use of the public Internet for aeronautical applications (ICAO Doc. 9855) provides guidelines on meteorological information for operations where time is not critical and the relevant aspects of the public Internet.
CCA RAC-03.760 Use of aeronautical fixed service communications and the public Internet - Meteorological bulletins (See RAC-03.760) The meteorological bulletins containing meteorological information for operations 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.
CCA RAC-03.770 Use of the aeronautical data link service - DVOLMET content (See RAC-03.770) The requirement to provide METAR and SPECI may be met through the application of the data link flight information service (D-FIS) entitled "Data link - Aerodrome routine meteorological report service (D-METAR)"; the requirement to provide TAF forecasts may be met through the D-FIS application entitled "Data link - Aerodrome forecast service (D-TAF)"; and the requirement to provide SIGMET and AIRMET messages may be met through the DFIS application entitled "Data link - SIGMET service (D-SIGMET)". The Manual on Data Link Applications for Air Traffic Services (ICAO Doc. 9694) provides detailed information on these data link services.
CCA RAC-03.775 Use of the aeronautical data link service - DVOLMET content (See RAC-03.775) The requirement to provide METAR and SPECI may be met through the application of the data link flight information service (D-FIS) entitled "Data link - Aerodrome routine meteorological report service (D-METAR)"; the requirement to provide TAF forecasts may be met through the D-FIS application entitled "Data link - Aerodrome forecast service (D-TAF)"; and the requirement to provide SIGMET and AIRMET messages may be met through the DFIS application entitled "Data link - SIGMET service (D-SIGMET)". The Manual on Data Link Applications for Air Traffic Services (ICAO Doc. 9694) provides detailed information on these data link services.