The Civil Aviation (Meteorological Service for International Air Navigation) (Amendment) Regulations, 2023
These Regulations may be cited by this name and are to be read together with the 2017 principal Regulations.
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These Regulations may be cited by this name and are to be read together with the 2017 principal Regulations. The principal Regulations are amended by replacing one named service title with another. This provision adds new defined terms for meteorological and aviation-related concepts. This section amends regulation 11 and renumbers some subregulations in the principal Regulations. The regulations are amended to add a new subregulation stating that the technical specification for the world area forecast system is as set out in the Second Schedule, subject to subregulation (2).
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Provisions of The Civil Aviation (Meteorological Service for International Air Navigation) (Amendment) Regulations, 2023
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These Regulations may be cited as the Civil
AI-assisted research summary: These Regulations may be cited by this name and are to be read together with the 2017 principal Regulations.
1. These Regulations may be cited as the Civil Aviation (Meteorological Service for International Air Navigation) (Amendment) Regulations, 2023 and shall be read as one with the Civil Aviation (Meteorological Service for International Air Navigation) Regulations, 2017 hereinafter the “principal Regulations”. referred to as General amendment - 2 Verify source ↗
The principal Regulations are amended
AI-assisted research summary: The principal Regulations are amended by replacing one named service title with another.
2. The principal Regulations are amended generally by deleting the words “Meteorological Service for International Air Navigation” wherever they appear and substituting for them the words “Meteorological Service for Air Navigation”. Amendment of regulation 2 - 3 Verify source ↗
The principal Regulations are amended in
AI-assisted research summary: This provision adds new defined terms for meteorological and aviation-related concepts.
3. The principal Regulations are amended in regulation 2 by adding in their appropriate alphabetical order the following new definitions: “Meteorological watch office (MWO)” means an 1 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) provide concerning information designated office to the occurrence or expected occurrence of specified en-route weather and other phenomena in the atmosphere that may affect the safety of aircraft area of its operations within responsibility; specified “Pre-eruption volcanic activity” means unusual and increasing volcanic activity which may presage a volcanic eruption; “Space weather centre (SWXC)” means a centre designated to monitor and provide advisory information on space weather phenomena expected radio communications, communications via satellite, surveillance GNSS-based systems or pose radiation risk to aircraft occupants; to affect high navigation frequency and by regional “State volcano observatory” means a volcano observatory, air designated to monitor active or navigation agreement potentially active volcanoes within a State and to provide information on volcanic activity to its associated area control centre or flight information centre, meteorological watch office and volcanic ash advisory centre; “World area forecast system (WAFS)” means a area worldwide system by which world forecast aeronautical meteorological en-route forecasts in uniform standardized for mats;”. provide centres Amendment of regulation 9 - 4 Verify source ↗
The principal Regulations are amended in
AI-assisted research summary: This section amends regulation 11 and renumbers some subregulations in the principal Regulations.
4. The principal Regulations are amended in regulation (9) by (a) adding immediately after subregulation (4) “(5) Subject the following new subregulation to subregulation (4), for the stated requirements suppliedmeteorological information shall be as specified in the First 2 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Schedule.” (b) renumbering subregulations (5), (6), (7), subregulations (8), (6),(7),(8),(9)(10) and (11) respectively. (9) and (10) as Amendment of regulation 11 Addition of regulation 15A 11 by adding
Part
Schedule.”
- 5 Verify source ↗
The principal Regulations are amended in
AI-assisted research summary: The regulations are amended to add a new subregulation stating that the technical specification for the world area forecast system is as set out in the Second Schedule, subject to subregulation (2).
5. The principal Regulations are amended in after regulation subregulation (2) the following new subregulation: “(3) Subject to subregulation (2) the technical specification related to world area forecast system shall be as specified in Second Schedule.” immediately - 6 Verify source ↗
The principal Regulations are amended by
AI-assisted research summary: This provision amends the principal Regulations by inserting a new regulation after regulation 15.
6. The principal Regulations are amended by adding immediately after regulation 15, the following new regulation: “Space weather centres - 15A Verify source ↗
(1) The space weather
AI-assisted research summary: The space weather center must monitor space weather and provide advisory information, including warnings about impacts, and related centers must keep a 24-hour watch.
15A.-(1) The space weather center shall monitor and provide advisory information on space weather phenomena in its area of responsibility by: (a) monitoring relevant ground-based, airborne and space- based observations to detect, and predict when possible, the existence of space weather phenomena that have an impact in following areas: the (i) high frequency radio communicati ons; (ii) communicati via ons satellite; 3 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) (iii) Global Navigation Satellite Systems based navigation and surveillance; and (iv) radiation exposure at flight levels; advisory (b) issuing information regarding the extent, and severity duration of the space weather phenomena that have an impact referred in to paragraph (a); (c) supplying the advisory information referred in paragraph (b) to: to and (i) area control centres, flight information centres aerodrome meteorologic al offices in its area of responsibilit y which may be affected; (ii) other Space Weather Centres; and 4 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) (iii) international operation meteorology databanks, international notice to air men offices and aeronautical fixed service internet- based services. Space Weather Centres shall maintain a 24- hour watch and in the event of interruption of the operation of the Center, its functions shall be carried out by another Space Weather Center as designated by the Service Provider State concerned. (2) (3) The service provider shall receive to arrange advisory information regarding the extent, severity and duration of weather space phenomena that have an impact referred in subregulation (1)”. the to Amendment of regulation 16 - 6 Verify source ↗
The principal Regulations are amended in
AI-assisted research summary: This section amends regulation 16 by adding a new subregulation setting the meteorological technical specification for observations and reports to the Third Schedule, and by renumbering the former subregulation (11) as (12).
6. The principal Regulations are amended in regulation 16 by (a) adding new sub regulation immediately after sub regulation 10 as follows: “(11) Subject to subregulation (10), meteorological technical specification for observations and reports shall be as specified in the Third Schedule.” (b) renumbering subregulation (11) as subregulation (12). 5 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Amendment of regulation 25 - 7 Verify source ↗
(1) The principal Regulations are amended
AI-assisted research summary: This section amends the principal Regulations by deleting regulation 25 and replacing it with new text.
7.-(1) The principal Regulations are amended by deleting regulation 25 and substituting for it the following: “Aircraft observati on - 25 Verify source ↗
(1) The routine for aircraft
AI-assisted research summary: Aircraft observation must follow the listed routine phases, and technical specifications are set in the Fourth Schedule.
25.-(1) The routine for aircraft observation shall be as follows: (a) routine aircraft observation during en-route and climb out phases of the flight; and (b) special and other non-routine aircraft observation during any phase of the flight.” (2) Subject to subregulation (1), the technical specification for aircraft observation and reports shall be as specified in the Fourth Schedule.”. Amendment of regulation 33 33 by adding - 8 Verify source ↗
The principal Regulations are amended in
AI-assisted research summary: The service provider must issue meteorological forecast technical content in line with the specification and detailed criteria in the Fifth Schedule.
8. The principal Regulations are amended in after regulation subregulation (2) the following new subregulation: “(3) The service provider shall issue meteorological forecast technical accordance with specification and detailed criteria specified in the Fifth Schedule.”. immediately the in Amendment of regulation 38 - 9 Verify source ↗
The principal Regulations are amended in
AI-assisted research summary: The service provider must issue the SIGMET information technical specification and the detailed criteria in the Sixth Schedule.
9. The principal Regulations are amended in regulation 38 by- (a) adding immediately after subregulation (5) the following new subregulation: “(6) The service provider shall issue SIGMET information technical specification and detailed criteria specified in the Sixth Schedule.” in accordance with the (b) renumbering subregulations (6) and (7) as subregulations (7) and (8) respectively. Amendment of regulation 41 - 10 Verify source ↗
The principal Regulations are amended in
AI-assisted research summary: This section amends the principal Regulations by adding a new paragraph requiring the relevant material to be collected, processed, stored, and issued in line with technical specifications and detailed criteria in the Seventh Schedule.
10. The principal Regulations are amended in 6 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) regulation 41(1) by adding paragraph (c) the following new paragraph: “(d) collected, processed, stored and issued in accordance with the technical specification and detailed criteria specified in the Seventh Schedule”. immediately after Amendment of regulation 45 - 11 Verify source ↗
The principal Regulations are amended in
AI-assisted research summary: This provision amends regulation 45 and requires meteorological information to be supplied according to the technical specification and detailed criteria in the Eighth Schedule, subject to subregulation (2).
11. The principal Regulations are amended in regulation 45 by- (a) adding immediately after sub regulation (2) the following new subregulation: “(3) Subject to subregulation (2), the meteorological information shall be supplied in accordance with the technical specification and detailed criteria specified in the Eighth Schedule.”; (b) renumbering subregulations (3) to (14) as subregulations (4) to (15) respectively. - 12 Verify source ↗
The principal Regulations are amended in
AI-assisted research summary: The amendment adds a rule requiring the service provider to provide service to operators and flight crew members in line with the Ninth Schedule specifications and detailed criteria, subject to subregulation (1).
12. The principal Regulations are amended in Regulation 52 by- (a) designating the contents of regulation 52 as 52(1); and (b) adding immediately after sub regulation (1) the following new sub as designated, regulation: “(2) Subject to subregulation (1), the service provider shall provide service to operators and flight crew members technical accordance with specification and detailed criteria specified in the Ninth Schedule”. the in by 53 adding - 13 Verify source ↗
The principal Regulations are amended in
AI-assisted research summary: A service provider must provide and use communication services in line with the technical specification and detailed criteria in the Tenth Schedule.
13. The principal Regulations are amended in after regulation subregulation (5) the following new subregulation” “(6) The service provider shall provide and use communication services in accordance with the technical specification and detailed criteria specified in the Tenth Schedule.” immediately Amendment of regulation 52 Amendment of regulation 53 Addition of Schedules
Part
Schedules
- 14 Verify source ↗
The principal Regulations are amended by
AI-assisted research summary: This provision amends the principal Regulations by adding two new schedules.
14. The principal Regulations are amended by adding immediately after regulation 71 the following Schedules: 7 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) 8 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) __________ FIRST SCHEDULE. ____________ (Made under regulation 9(5)) __________ METEOROLOGICAL INFORMANTION STATED REQUIREMENTS PART A OPERATIONALLYDESIRABLEACCURACY OF MEASUREMENT OROBSERVATION Element to be observed operationally desirable accuracy of measurement or observation* Mean surface wind Speed: ± 0.5 m/s (1 kt) up to 5 m/s (10 kt) ± 10% above 5 m/s (10 kt) Variations from the mean surface wind longitudinal and lateral components Visibility ± 10% between 600 m and 1 500 m ± 20% above 1 500 m Runway visual range ± 25 m between 400 m and 800 m ± 10% above 800 m Cloud amount Cloud height (330ft) ± 10% above 100 m (330 ft) Direction: ±10° ± 1 m/s (2 kt), in terms of ± 50 m up to 600m ± 10 m up to 400m ± 1okta ± 10 m (33 ft) up to 100 m Air temperature and dew-point temperature± 1°C Pressure value (QNH, QFE) ± 0.5hPa * The operationally desirable accuracy is not intended as an operational requirement; it is to be understood as a goal that has been expressed by the operators. Note. — Guidance on the uncertainties of measurement or observation can be found in the Guide 9 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) to Meteorological Instruments and Methods of Observation (WMO-No. 8). PART B OPERATIONALLYDESIRABLEACCURACY OFFORECASTS Note. — If the accuracy of the forecasts remains within the operationally desirable range shown in the second column, for the percentage of cases indicated in the third column, the effect of forecast errors is not considered serious in comparison with the effects of navigational errors and of other operational uncertainties. Element to be forecast Operationally desirable accuracy of forecasts Minimum percentage of cases within range TAF Wind direction ±20° 80% of cases Windspeed ± 2.5 m/s(5kt) 80% of cases Visibility ± 30% between 800 m and 10 km ± 200 m up to 800m 80% of cases Precipitation Occurrence or non-occurrence 80% of cases Cloud amount Occurrence or non-occurrence of BKN or OVC between 450 m (1 500 ft) and 3 000 m (10 000 ft) One category below 450 m (1 500ft) 70% of cases Cloud height ± 30% between 300 m (1 000 ft) and 3 000 m (10 000 ft) ± 30 m (100 ft) up to 300 m (1 000ft) 70% of cases Air temperature ±1°C 70% of cases TREND FORECAST Wind direction ±20° 90% of cases Windspeed ± 2.5 m/s(5kt) 90% of cases Visibility ± 30% between 800 m and 10 km ± 200 m up to 800m 90% of cases Precipitation Occurrence or non-occurrence 90% of cases 10 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Element to be forecast Operationally desirable accuracy of forecasts Minimum percentage of cases within range Cloud amount Occurrence or non-occurrence of BKN or OVC between 450 m (1 500 ft) and 3 000 m (10 000 ft) 90% of cases One category below 450 m (1 500ft) Cloud height ± 30% between 300 m (1 000 ft) and 3 000 m (10 000 ft) ± 30 m (100 ft) up to 300 m (1 000ft) 90% of cases FORECAST FOR TAKE-OFF Wind direction ± 20° 90% of cases Wind speed ± 2.5 m/s (5 kt) up to 12.5 m/s (25 kt) 90% of cases Air temperature ± 1°C Pressure value (QNH) ± 1 hPa AREA, FLIGHT AND ROUTE FORECASTS 90% of cases 90% of cases Upper-air temperature ± 2°C (Mean for 900 km(500NM)) 90% of cases Relative humidity ±20% 90% of cases Upper wind (Modulus of vector difference for 900 km (500 NM)) ± 5 m/s (10kt) Significant en-route weather phenomena and cloud Occurrence or non-occurrence Location: ± 100 km (60 NM) Vertical extent: ± 300 m (1 000 ft) Flight level of tropopause: ± 300 m (1 000 ft) Max wind level: ± 300 m (1 000 ft) 80% of cases 70% of cases 70% of cases 80% of cases 80% of cases Element to be observed operationally desirable accuracy of measurement or observation* _______________ SECOND SCHEDULE _______________ 11 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) (Made under regulation 11(3))) TECHNICAL SPECIFICATIONS RELATED TO GLOBAL SYSTEMS, SUPPORTING CENTRES AND METEOROLOGICAL OFFICES
Part
PART B
- 1
AI-assisted research summary: World area forecast centres (WAFCs) must use uniform formats and codes when supplying forecasts.
1.1 WORLD AREA FORECAST SYSTEM Formats and codes World area forecast centres (WAFCs) shall adopt uniform formats and codes for the supply of forecasts. - 1 Verify source ↗
2.1
AI-assisted research summary: A WAFC must prepare specified weather forecasts four times a day and disseminate each forecast in the stated order within the required time limit.
1.2.1 The forecasts of upper winds; upper-air temperature; and humidity; direction, speed and flight level of maximum wind; flight level and temperature of tropopause, areas of cumulonimbus clouds, icing, clear-air and in-cloud turbulence, and geopotential altitude of flight levels shall be prepared four times a day by a WAFC and shall be valid for fixed valid times at 6, 9, 12, 15, 18, 21, 24, 27, 30, 33 and 36 hours after the time (0000, 0600, 1200 and 1800 UTC) of the synoptic data on which the forecasts were based. The dissemination of each forecast shall be in the above order and shall be completed as soon as technically feasible but not later than 6hours after standard time of observation. - 1 Verify source ↗
2.2
AI-assisted research summary: A WAFC must prepare grid point forecasts containing the listed wind, temperature, humidity, cloud, icing, turbulence, and geopotential altitude information at the specified flight levels.
1.2.2 The grid point forecasts prepared by a WAFC shall comprise: (a) wind and temperature data for flight levels 50 (850 hPa), 80 (750 hPa), 100 (700 hPa), 140 (600 hPa), 180 (500 hPa), 210 (450 hPa), 240 (400 hPa), 270 (350 hPa), 300 (300 hPa), 320 (275 hPa), 340 (250 hPa), 360 (225hPa), 390 (200hPa), 410 (175hPa), 450 (150hPa), 480 (125hPa) and 530(100hPa); (b) (c) flight level and temperature of tropopause; direction, speed and flight level of maximum wind; (d) and 180 (500hPa); humidity data for flight levels 50 (850hPa), 80 (750hPa), 100 (700hPa), 140 (600hPa) (e) horizontal extent and flight levels of base and top of cumulonimbus clouds; (f) (500 hPa), 240 (400 hPa) and 300 (300hPa); icing for layers centred at flight levels 60 (800 hPa), 100 (700 hPa), 140 (600 hPa), 180 (g) (300 hPa), 340 (250 hPa), 390 (200 hPa) and 450 (150hPa); clear-air turbulence for layers centred at flight levels 240 (400 hPa), 270 (350 hPa), 300 (h) (500 hPa), 240 (400 hPa) and 300 (300 hPa); and in-cloud turbulence for layers centred at flight levels 100 (700 hPa), 140 (600 hPa), 180 Note 1.— Layers centred at a flight level referred to in f) and h) have a depth of 100 hPa. 12 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Note 2. — Layers centred at a flight level referred to in g) have a depth of 50 hPa. geopotential altitude data for flight levels 50 (850 hPa), 80 (750 hPa), 100 (700 hPa), (i) 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 Verify source ↗
2.3
AI-assisted research summary: WAFCs must issue the relevant grid point forecasts in binary code form, using the GRIB code form prescribed by WMO.
1.2.3 using the GRIB code form prescribed by the World Meteorological Organization (WMO). The foregoing grid point forecasts shall be issued by a WAFC in binary code form Note.— The GRIB code form is contained in the Manual on Codes (WMO-No. 306), Volume I.2, Part B — Binary Codes.
Part
Part B — Binary Codes.
- 1 Verify source ↗
2.4
AI-assisted research summary: Grid point forecasts must be prepared by a WAFC in a regular grid.
1.2.4 with a horizontal resolution of 1.25° of latitude and longitude. The foregoing grid point forecasts shall be prepared by a WAFC in a regular grid - 1
AI-assisted research summary: Section title: “1.3 Significant weather (SIGWX) forecasts”.
1.3 Significant weather (SIGWX) forecasts - 1 Verify source ↗
3.1.1
AI-assisted research summary: A WAFC must prepare SIGWX forecasts of significant en-route weather phenomena four times a day and complete dissemination as soon as technically feasible, but no later than 9 hours after the standard time of observation.
1.3.1.1 Forecasts of significant en-route weather phenomena shall be prepared as SIGWX forecasts four times a day by a WAFC and shall be valid for fixed valid times at 24 hours after the time (0000, 0600, 1200 and 1800 UTC) of the synoptic data on which the forecasts were based. The dissemination of each forecast shall be completed as soon as technically feasible but not later than 9 hours after standard time of observation. - 1 Verify source ↗
3.1.2
AI-assisted research summary: SIGWX forecasts must be issued in binary code form using the BUFR code form.
1.3.1.2 dbyWMO. SIGWXforecastsshallbeissuedinbinarycodeformusingtheBUFRcodeformprescribe Note.— The BUFR code form is contained in the Manual on Codes (WMO-No. 306), Volume I.2, Part B — Binary Codes. - 1 Verify source ↗
3.2 Types of SIGWX forecasts
AI-assisted research summary: SIGWX forecasts are to be issued as high-level forecasts for flight levels 250 to 630.
1.3.2 Types of SIGWX forecasts SIGWX forecasts shall be issued as high-level SIGWX forecasts for flight levels between 250 and 630. Note.— Medium-level SIGWX forecasts for flight levels between 100 and 250 for limited geographical areas will continue to be issued until such time that flight documentation to be generated from the gridded forecasts of cumulonimbus clouds, icing and turbulence fully meets user requirements. - 1 Verify source ↗
3.3 Types of SIGWX forecasts
AI-assisted research summary: SIGWX forecasts must include specified aviation weather hazards and related chart information.
1.3.3 Types of SIGWX forecasts SIGWX forecasts shall include the following items: (a) is expected to reach or exceed 17 m/s (34kt); tropical cyclone provided that the maximum of the 10-minute mean surface wind speed 13 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) (b) (c) (d) (e) (f) severe squall lines; moderate or severe turbulence (in cloud or clear air); moderate or severe icing; widespread sandstorm/dust storm; cumulonimbus clouds associated with thunderstorms and with a) toe); Note.— Non-convective cloud areas associated with in-cloud moderate or severe turbulence and/or moderate or severe icing are to be included in the SIGWX forecasts. (g) (h) flight level of tropopause; jet streams; (i) information on the location of volcanic eruptions that are producing ash clouds of significance to aircraft operations, comprising: volcanic eruption symbol at the location of the volcano and, in a separate text box on the chart, the volcanic eruption symbol, the name of the volcano (if known) and the latitude/longitude of the eruption. In addition, the legend of SIGWX charts should indicate “CHECK SIGMET, ADVISORIES FOR TC AND VA, AND ASHTAM AND NOTAM FOR VA”; and (j) information on the location of a release of radioactive materials into the atmosphere of significance to aircraft operations, comprising: the radioactive materials in the atmosphere symbol at the location of the release and, in a separate text box on the chart, the radioactive materials in the atmosphere symbol, latitude/longitude of the site of the release, and (if known) the name of site of the radioactive source. In addition, the legend of SIGWX charts on which a release of radiation is indicated should contain “CHECK SIGMET AND NOTAM FOR RDOACTCLD”. Note 1. — Medium-level SIGWX forecasts include all the items above. Note 2.— Items to be included in low-level SIGWX forecasts (i.e., flight levels below 100) are included in Schedule 5. - 1 Verify source ↗
3.4 Criteria for including items in SIGWX forecasts
AI-assisted research summary: SIGWX forecasts must follow specific inclusion rules for upper-level items, cumulonimbus clouds, volcanic eruption or radioactive material symbols, and priority when items overlap.
1.3.4 Criteria for including items in SIGWX forecasts. The following criteria shall be applied for SIGWX forecasts: (a) upper levels of the SIGWX forecast. items a) to f) in 1.3.3 shall only be included if expected to occur between the lower and (b) expected occurrence of cumulonimbus clouds: the abbreviation “CB” shall only be included when it refers to the occurrence or 1) area concerned. affecting an area with a maximum spatial coverage of 50 per cent or more of the 2) along a line with little or no space between individual clouds; or 14 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) 3) embedded in cloud layers or concealed by haze; (c) the inclusion of “CB” shall be understood to include all weather phenomena normally associated with cumulonimbus clouds, i.e., thunderstorm, moderate or severe icing, moderate or severe turbulence and hail. (d) where a volcanic eruption or a release of radioactive materials into the atmosphere warrants the inclusion of the volcanic eruption symbol or the radioactive materials in the atmosphere symbol in SIGWX forecasts, the symbols shall be included on SIGWX forecasts irrespective of the height to which the ash column or radioactive material is reported or expected to reach; and (e) in the case of co-incident or the partial overlapping of items a), i) and j) in 1.3.3, the highest priority shall be given to item i), followed by items j) and a). The item with the highest priority shall be placed at the location of the event, and a narrow shall be used to link the location of the other item(s) to its associated symbol or textbox. - 2
AI-assisted research summary: This section heading concerns aerodrome meteorological offices and the use of WAFS products.
2.1 AERODROME METEOROLOGICALOFFICES Use of world area forecast system (WAFS) products. - 2 Verify source ↗
1.1
AI-assisted research summary: Aerodrome meteorological offices must use WAFS forecasts from the WAFCs when preparing flight documentation if the forecasts cover the intended flight path, unless the meteorological authority and operator agree otherwise.
2.1.1 Aerodrome meteorological offices shall use WAFS forecasts issued by the WAFCs in the preparation of flight documentation, whenever these forecasts cover the intended flight path in respect of time, altitude and geographical extent, unless otherwise agreed between the meteorological authority and the operator concerned. - 2 Verify source ↗
1.2
AI-assisted research summary: WAFS GRIB and BUFR data received must be decoded into standard WAFS charts, and the meteorological content and originator identification must not be changed.
2.1.2 In order to ensure uniformity and standardization of flight documentation, the WAFS GRIB and BUFR data received shall be decoded into standard WAFS charts in accordance with relevant provisions in this Annex, and the meteorological content and identification of the originator of the WAFS forecasts shall not be amended. - 2
AI-assisted research summary: Aerodrome meteorological offices using WAFS BUFR data must immediately notify the relevant WAFC if significant discrepancies are found or reported in certain WAFS SIGWX forecasts; the WAFC that receives the message must acknowledge receipt and briefly say what was reported and any action taken.
2.2 discrepancies Notification of WAFC concerning significant Aerodrome meteorological offices using WAFS BUFR data shall notify the WAFC concerned immediately if significant discrepancies are detected or reported in respect of WAFS SIGWX forecasts concerning: (a) occurring at a squall line, and sandstorms/dust storms; and icing, turbulence, cumulonimbus clouds that are obscured, frequent, embedded or (b) significance to aircraft operations. volcanic eruptions or a release of radioactive materials into the atmosphere, of The WAFC receiving the message shall acknowledge its receipt to the originator, together with a brief comment on the report and any action taken, using the same means of communication employed by the originator. 15 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Note. — Guidance on reporting significant discrepancies is provided in the Manual of Aeronautical Meteorological Practice (Doc 8896). - 3
AI-assisted research summary: This provision is a heading about volcanic ash advisory centres and their advisory information.
3.1 VOLCANIC ASH ADVISORY CENTRES Volcanic ash advisory information - 3 Verify source ↗
1.1
AI-assisted research summary: Advisory information on volcanic ash must follow the template, using approved ICAO abbreviations and self-explanatory numbers; if no approved ICAO abbreviations are available, use English plain language text kept to a minimum.
3.1.1 The advisory information on volcanic ash issued in abbreviated plain language, using approved ICAO abbreviations and numerical values of self-explanatory nature, shall be in accordance with the template shown in Table A2-1. When no approved ICAO abbreviations are available, English plain language text, to be kept to a minimum, shall be used. - 3 Verify source ↗
1.2
AI-assisted research summary: Volcanic ash advisory information must also be disseminated in IWXXM GML form.
3.1.2 As of 5 November 2020, volcanic ash advisory information shall be disseminated in IWXXM GML form in addition to the dissemination of this advisory information in accordance with 3.1.1. - 3 Verify source ↗
1.3
AI-assisted research summary: Volcanic ash advisory information in Table A2-1, when shown graphically, must follow the Third Schedule and be issued in PNG format.
3.1.3 The volcanic ash advisory information listed in Table A2-1, when prepared in graphical format, shall be as specified in Third Schedule, and issued using the portable network graphics (PNG) format. - 4 Verify source ↗
1 Information from State volcano observatories
AI-assisted research summary: State volcano observatories must send specified volcano information to their associated ACCs/FICs, MWO, and VAAC; they may use the VONA format.
4.1 Information from State volcano observatories The information required to be sent by State volcano observatories to their associated area control centres (ACCs)/flight information centres (FICs), meteorological watch office (MWO) and VAAC shall comprise: for significant pre-eruption volcanic activity: the date/time (UTC) of report; name and, (a) if known, number of the volcano; location(latitude/longitude); and description of volcanic activity; and (b) for volcanic eruption: the date/time (UTC) of report and time of eruption (UTC) if different from time of report; name and, if known, number of the volcano; location (latitude/longitude); and description of the eruption including whether an ash column was ejected and, if so, an estimate of height of ash column and the extent of any visible volcanic ash cloud, during and following an eruption; and (c) cessation (UTC); name and, if known, number of the volcano; and location(latitude/longitude). for volcanic eruption cessation: the date/time (UTC) of report and time of eruption Note 1. — Pre-eruption volcanic activity in this context means unusual and/or increasing volcanic activity which could presage a volcanic eruption. 16 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Note 2. — The State volcano observatories may use the Volcano Observatory Notice for Aviation (VONA) format to send information to their associated ACCs/FICs, MWO and VAAC. The VONA format is included in the Handbook on the International Airways Volcano Watch (IAVW) — Operational Procedures and Contact List (Doc 9766) which is available on the ICAO website. - 5 Verify source ↗
1 Tropical cyclone advisory information
AI-assisted research summary: This section is titled “Tropical cyclone advisory information.”
5.1 Tropical cyclone advisory information - 5 Verify source ↗
1.1
AI-assisted research summary: Advisory information on tropical cyclones must be issued when the maximum 10-minute mean surface wind speed is expected to reach or exceed 17 m/s (34 kt).
5.1.1 The advisory information on tropical cyclones shall be issued for tropical cyclones when the maximum of the 10-minute mean surface wind speed is expected to reach or exceed 17 m/s (34 kt) during the period covered by the advisory. - 5 Verify source ↗
1.2
AI-assisted research summary: Advisory information on tropical cyclones must use abbreviated plain language, approved ICAO abbreviations, and self-explanatory numerical values, following the template in Table A2-2.
5.1.2 The advisory information on tropical cyclones disseminated in abbreviated plain language, using approved ICAO abbreviations and numerical values of self-explanatory nature, shall be in accordance with the template shown in Table A2-2. - 5 Verify source ↗
1.3
AI-assisted research summary: Tropical cyclone advisory centres must disseminate tropical cyclone advisory information in IWXXM GML form, as well as in abbreviated plain language.
5.1.3 Tropical cyclone advisory centres shall disseminate tropical cyclone advisory information in IWXXM GML form in addition to the dissemination of this advisory information in abbreviated plain language in accordance with 5.1.2 The tropical cyclone advisory information listed in Table A2-2, when prepared in - 5 Verify source ↗
1.4
AI-assisted research summary: The graphical format must follow Schedule 1 and be issued in PNG format.
5.1.4 graphical format, shall be as specified in Schedule 1 and issued using the PNG format. - 6 Verify source ↗
1.1
AI-assisted research summary: Space weather advisory information must be issued in abbreviated plain language, using approved ICAO abbreviations and self-explanatory numerical values; if no approved ICAO abbreviations are available, English plain language must be used as briefly as possible.
6.1.1 Advisory information on space weather shall be issued in abbreviated plain language, using approved ICAO abbreviations and numerical values of self-explanatory nature, and shall be in accordance with the template shown in Table A2-3. When no approved ICAO abbreviations are available, English plain language text, to be kept to a minimum, shall be used. Space weather advisory information shall be disseminated in IWXXM GML for, in - 6 Verify source ↗
1.2
AI-assisted research summary: Space weather advisory information must be disseminated in IWXXM GML form, in addition to abbreviated plain-language dissemination under 6.1.1.
6.1.2 addition to the dissemination of space weather advisory information in abbreviated plain language in accordance with 6.1.1. Space weather advisory information shall be disseminated in IWXXM GML form, - 6 Verify source ↗
1.3
AI-assisted research summary: This item says the advisory information must also be disseminated in abbreviated plain language, consistent with 6.1.1.
6.1.3 in addition to the dissemination of this advisory information in abbreviated plain language in accordance with 6.1.1. - 6 Verify source ↗
1.4
AI-assisted research summary: Weather advisory information must use the abbreviations listed below for the specified space weather effects.
6.1.4 weather advisory information, using their respective abbreviations as indicated below: One or more of the following space weather effects shall be included in the space HF communications (propagation, absorption) HF COM Communications via satellite (propagation, absorption) SATCOM GNSS-based navigation and surveillance (degradation) radiation at flight levels (increased exposure) GNSS RADIATION 17 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) - 6 Verify source ↗
1.5
AI-assisted research summary: Space weather advisory information must include the listed intensity abbreviations.
6.1.5 using their respective abbreviations as indicated below: The following intensities shall be included in space weather advisory information, moderate severe MOD SEV Updated advisory information on space weather phenomena shall be issued as - 6 Verify source ↗
1.6
AI-assisted research summary: This provision sets out the required template fields for a volcanic ash advisory message, showing which items are mandatory, optional, or conditional.
6.1.6 necessary but at least every six hours until such time as the space weather phenomena are no longer detected and/or are no longer expected to have an impact. Table A2-1. Template for advisory message for volcanic ash Key: M = inclusion mandatory, part of every message; O = inclusion optional; C = inclusion conditional, included whenever applicable; = = a double line indicates that the text following it should be placed on the subsequent line. Note 1.— The ranges and resolutions for the numerical elements included in advisory messages for volcanic ash are shown in Appendix 6, Table A6-4. Note 2.— The explanations for the abbreviations can be found in the Procedures for Air Navigation Services — ICAO Abbreviations and Codes (PANS-ABC, Doc 8400). Note 3.— Inclusion of a “colon” after each element heading is mandatory. Note 4.— The numbers 1 to 18 are included only for clarity and they are not part of the advisory message, as shown in the example. Element Detailed content Template(s) Examples 1 Identification of the type of message (M) Type of message VA ADVISORY VA ADVISORY 2 tatus indicator (C)1 Indicator of test or exercise STATUS:TEST EXER 3 Time of origin (M) Year, month, day, time in UTC DTG: nnnnnnnn/nnnnZ or STATUS:TEST STATUS: EXER DTG: 923/0130Z 20080 18 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) 4 Name of VAAC Name of VAAC VAAC: (M) VAAC: n TOK nnnnnnnnnnn YO 5 Name of volcano (M) Name and IAVCEI1 number of volcano VOLCANO: VOLCANO: n nnnnnnnnnnnnnnnnnn nnn[nnnnnn] or UNKNOWN orUNNAMED KAR YMSKY1000- 13VOLCANO: UNN AMED 6 Location of volcano (M) Location of volcano in degrees and minutes PSN: PSN: N N5403 nnnnorSnnnn E15927 7 State or region (M) State, or region if ash is not reported over a State Wnnnnnor Ennnnn or UNKNOWN AREA: PSN: NOWN AREA: n UNK RUSS nnnnnnnnnnnnnnn IA 8 Summit elevation (M) Summit elevation in m (or ft) SUMMITELEV: nnnM (ornnnnnFT) 9 Advisory number (M) Advisory number: year in full and message number (separate sequence for each volcano) ADVISORYNR: nnn/nnnn SUMMIT ELEV: 1536M ADVISORY NR: 2008/4 n n 10 Information source (M) Information source using free text INFOSOURCE: ree text up to 32characters F INFO SOURCE: MTSAT-1R KVERT KEMSD 19 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) 11 Colour code (O) Aviation colour code AVIATIONCOLOUR R ED or ORANGE orYELLOW CODE: o r GREEN or UNKNOWN or NOTGIVEN or NIL AVIATION RED COLOUR CODE: Element Detailed content Template(s) Examples 12 Eruption details (M) 13 Time of Eruption details (including date/time of eruption(s)) Day and time (in UTC) ERUPTION DETAILS: OBS (or EST) VA DTG: Free text up to 64 characters or UNKNOW nn/nnnnZ N ERUPTI ON DETAIL S: OBS VA DTG: ERUPTI ON AT 2008092 3/0000Z FL300 23/0100 REPORT Z ED observation (or of observation estimation) of ash (M) (or estimation) of volcanic Ash 14 Observed or Horizontal (in degrees estimated ash and minutes) and OBS VA CLD or EST VA CLD: cloud (M) vertical extent at the time of observation of the observed or estimated ash cloud or, if the base is unknown, the top of the observed or estimated ash cloud; 20 TOP FLnnnor SFC/FLnnn or FLnnn/nnn [nnKM WID LINE2 BTN (nnNM WID LINE BTN)] Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] OBS VA CLD: FL250/3 00 N5400 E15930 – N5400 E16100 – N5300 E15945 MOV SE 20KT SFC/FL2 00 N5130 E16130 N5130 – E16230 N5230 – E16230 N5230 – E16130 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Movement of the observed or estimated ash cloud 15 Forecast height Day and time (in UTC) FCST VA CLD +6 HR: and position of the ash clouds (+6 HR) (M) (6 hours from the “Time of observation estimation) (or of ash” given in Item 12); MOV SE 15KT TOP FL240 40KMH MOV W VA NOT FM IDENTI WIND SATELL FIABLE FL050/0 ITE 180/12M 70 DATA PS 23/0700Z FCST VA CLD +6 HR: FL250/35 0 N5130 E16030 – N5130 E16230 – N5330 E16230 – or Ennn[nn][ – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] MOV N nnKMH (or KT) or MOV NE nnKMH (or KT) or MOV E nnKMH (or KT) or MOV SE nnKMH (or KT) or MOV S nnKMH (or KT) or MOV SW nnKMH (or KT) or MOV W nnKMH (or KT) or MOV NW nnKMH (or nn/nnnnZ KT)3 SFC or FLnnn/[FL]nnn or [nnKM WID LINE2 VA NOT BTN (nnNM WID LINE IDENTIFIA BTN)] BLE FM Nnn[nn] or Snn[nn] SATELLIT Wnnn[nn] or E DATA Ennn[nn] – WIND Nnn[nn] or Snn[nn] FLnnn/nnnn Wnnn[nn] or nn/nn[n]MP Ennn[nn][ – S (or KT)4 Nnn[nn] or Snn[nn] or Wnnn[nn] or WIND FLnnn/nnn VRBnnMPS (or KT) or WIND SFC/FLnnn nnn/nn[n]M PS (or KT) or WIND SFC/FLnnn VRBnnMPS (or KT) 21 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Forecast height and position (in degrees and minutes) for each cloud mass for that fixed valid time Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]]3 or NO VA EXP or NOT AVBL or NOT PROVIDED N5330 SFC/FL18 E16030 0 N4830 E16330 – N4830 E16630 – N5130 E16630 – N5130 E16330 NO VA EXP NOT AVBL NOT PROVIDE D Element Detailed content Template(s) Examples 22 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) FCST VA CLD +12 HR: 23/1300Z SFC/FL270 N4830 E16130 – N4830 E16600 – N5300 E16600 – N5300 E16130 NO VA EXP NOT AVBL NOT PROVIDED FCST VA CLD +18 HR: 23/1900Z NO VA EXP NOT AVBL NOT PROVIDED GN. NO.352 (Contd.) 16 Forecast height and position of the ash clouds (+12 HR) (M) 17 Forecast height and position of the ash clouds (+18 HR) (M) FCST VA CLD +12 HR: FCST VA CLD +18 HR: Day and time (in UTC) (12 hours from the “Time of observation (or estimation) of ash” given in Item12); Forecast height and position (in degrees and minutes) for each cloud mass for that fixed valid time Day and time (in UTC) (18 hours from the “Time of observation (or estimation) of ash” given in Item12); Forecast height and position (in degrees and minutes) for each cloud mass for that fixed valid time 23 nn/nnnnZ SFC or FLnnn/[FL]nn n [nnKM WID LINE2 BTN (nnNM WID LINE BTN)] Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn][ – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or nn/nnnnZ Ennn[nn] – SFC or Nnn[nn] or FLnnn/[FL]nn Snn[nn] n Wnnn[nn] or [nnKM WID Ennn[nn]]3 LINE2 BTN or (nnNM WID NO VA EXP LINE BTN)] or Nnn[nn] or NOT AVBL Snn[nn] or Wnnn[nn] or NOT Ennn[nn] – PROVIDED Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn][ – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]]3 or NO VA EXP or NOT AVBL or NOT PROVIDED Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) 18 Remarks (M) Remarks, as necessary RMK: RMK: Free text up to 256 characters or NIL 19 Next advisory (M) Year, month, day and time in UTC NXT ADVISOR Y: NXT ADVISOR Y: LATEST REP FM KVERT (0120Z) INDICATES ERUPTION HAS CEASED. TWO DISPERSING VA CLD ARE EVIDENT 20080923/073 ON 0Z SATELLITE IMAGERY NO LATER THAN NIL nnnnnnnn/nnn nZ NO FURTHER ADVISORIE S WILL BE ISSUED BY nnnnnnnn/nnn nZ nnnnnnnn/nnn nZ or NO LATER THAN nnnnnnnn/nnn nZ or NO FURTHER ADVISORIE S or WILL BE ISSUED BY nnnnnnnn/nnn nZ Notes.— - 1 Verify source ↗
Used only when the message issued to indicate that a test or an exercise is taking place
AI-assisted research summary: A message marked with “TEST” or “EXER” is for testing or exercise use only.
1. Used only when the message issued to indicate that a test or an exercise is taking place. When the word “TEST” or the abbreviation “EXER” is included, the message may contain information that should not be used operationally or will otherwise end immediately after the word "TEST". [Applicable 7 November 2019] International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI). - 3 Verify source ↗
A straight line between two points drawn on a map in the Mercator projection or a straight
AI-assisted research summary: This provision defines a straight line for map-related purposes.
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. - 5 Verify source ↗
Section 5
AI-assisted research summary: This section shows example formats for aviation advisory messages, including volcanic ash and tropical cyclone advisories.
5. If ash reported (e.g., AIREP) but not identifiable from satellite data. Example A2-1. Advisory message for volcanic ash VA ADVISORY DTG: VAAC: 20080923/0130Z TOKYO VOLCANO: KARYMSKY 1000-13 PSN: AREA: SUMMIT ELEV: ADVISORY NR: INFO SOURCE: N5403 E15927 RUSSIA 1536M 2008/4 MTSAT-1R KVERT KEMSD 24 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) AVIATION COLOUR CODE: ERUPTION DETAILS: OBS VA DTG: OBS VA CLD: FCST VA CLD +6 HR: FCST VA CLD +12 HR: FCST VA CLD +18 HR: RMK: NXT ADVISORY: RED ERUPTION AT 20080923/0000Z FL300 REPORTED 23/0100Z FL250/300 N5400 E15930 – N5400 E16100 – N5300 E15945 MOV SE 20KT SFC/FL200 N5130 E16130 – N5130 E16230 – N5230 E16230 – N5230 E16130 MOV SE 15KT 23/0700Z FL250/350 N5130 E16030 – N5130 E16230 – N5330 E16230 – N5330 E16030 SFC/FL180 N4830 E16330 – N4830 E16630 – N5130 E16630 – N5130 E16330 23/1300Z SFC/FL270 N4830 E16130 – N4830 E16600 – N5300 E16600 – N5300 E16130 23/1900Z NO VA EXP LATEST REP FM KVERT (0120Z) INDICATES ERUPTION HAS CEASED. TWO DISPERSING VA CLD ARE EVIDENT ON SATELLITE IMAGERY Table A2-2. Template for advisory message for tropical cyclones 20080923/0730Z Key: M = inclusion mandatory, part of every message. C = inclusion conditional, included whenever applicable; = = adoublelineindicatesthatthetextfollowingitshouldbeplacedonthesubsequentline. Note 1.— The ranges and resolutions for the numerical elements included in advisory messages for tropical cyclones are shown in Appendix 6, Table A6-4. Note 2.— The explanations for the abbreviations can be found in the PANS-ABC (Doc 8400). Note Note 3.— Inclusion of a “colon” after each element heading is mandatory. Note 4.— The numbers 1 to 21 are included only for clarity and they are not part of the advisory message, as shown in the example. Element Detailed content Template(s) Examples 25 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Type of message TC ADVISORY TC ADVISORY Identificat ion of the type of message( M) Status indicator (C)1 1 2 3 4 5 6 7 Indicator of test or exercise STAT US: TEST or EXER TEST EXER STATU S: STATU S: DTG: 20040925/1600Z Time of origin(M) Year, month, day and time in UTC of issue DTG: nnnnnnnn/nnn nZ TCAC: nnnnor nnnnnnnnnn TCAC: YUFO1 TCAC: MIAMI TC: nnnnnnnnnnnn or NN TC: GLORIA nnnn/[n][n]nn ADVIS ORYN R: 2004/13 ADVIS ORY NR: OBS PSN: nn/nnnnZ Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] OBS PSN 25/1800Z N2706 W07306 Name of TCAC(M) Name of TCAC (location indicator or full name) Name of tropical cyclone(M ) Name of tropical cyclone or “NN” for unnamed tropical cyclone Advisory number(M ) Observed position of the centre (M) Advisory number.Year in full and message number(separat e sequencefor each cyclone) Day and time in UTCand position of the centre of the tropical cyclone (in degrees and minutes)and minutes) 26 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) 8 Observed CB cloud (C) ) CB: Location of CB cloud (referring to latitude and longitude (in degrees and minutes)) and vertical extent (flight level CB: WI 250NM OF TC CENTRE TOP FL500 WI nnnKM (or nnnNM) OF TC CENTRE or WI4 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] and TOP [ABV or BLW] FLnnn(or KT) or ESE nnKMH (or KT) or SE nnKMH (or KT) or SSE nnKMH (or KT) or S nnKMH (or KT) or SSW nnKMH (or KT) or SW nnKMH (or KT) or WSW nnKMH (or KT) or W nnKMH (or KT) or WNW nnKMH (or KT) or NW nnKMH (or KT) or NNW nnKMH (or KT) or SLW or STNR 27 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) 10 Central pressure (M) Central pressure (in hPa) Element Detailed content 11 Maximum surface wind(M) Maximum surface wind near the centre (mean over 10 minutes, in m/s (orkt)) C: nnnHPA C: 965HPA Template(s) Examples MAX WIND: nn[n]MPS (or nn[n]KT) MAX WIND: 22MPS 12 Forecast of centre position Day and time (in UTC) FCST PSN +6 HR: nn/nnnnZ FCST PSN +6 HR: 25/2200 Z Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] N2748 W07350 (+6 HR) (M) (6 hours from the “DTG” Forecast of centre position given in Item 2); Forecast position (in degrees and minutes) of the centre of the tropical cyclone 13 Forecast of maximum (M) surface wind (+6 HR) Forecast of maximum surface wind (6 hours after the “DTG” given in Item 2) FCST MAX WIND +6 HR: nn[n]MPS (or nn[n]KT) 22MPS FCST MAX WIND +6 HR: 14 Forecast of centre Day and time (in UTC) FCST PSN +12 HR: nn/nnnnZ FCST PSN +12 HR: 26/0400 Z position (12 hours from the Nnn[nn] or Snn[nn] Wnnn[nn] or 28 N2830 W07430 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) (+12 HR)(M) “DTG” given in Item 2); Ennn[nn] Forecast position (in degrees and minutes) of the centre of cyclone the tropical Forecast of maximum surface wind (12 hours after the “DTG” given in Item 2) 15 Forecast of maximum surface wind (+12 HR)(M) FCST MAX WIND +12 HR: nn[n]MPS (or nn[n]KT) 22MPS FCST MAX WIND +12 HR: 16 Forecast of centre Day and time (in UTC) FCST PSN +18 HR: nn/nnnnZ FCST PSN +18 HR: 26/1000 Z position (18 hours from the (+18 HR)(M) “DTG” given in Item 2); Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] N2852 W07500 Forecast position (in degrees and minutes) of the centre of the tropical cyclone 17 Forecast of maximum surface wind (+18 HR)(M) FCST MAX WIND +18 HR: Forecast of maximum surface wind (18 hours after the “DTG” given in Item 2) nn[n]MPS (or nn[n]KT) 21MPS FCST MAX WIND +18 HR: 18 Forecast of centre Day and time (in UTC) nn/nnnnZ FCST PSN +24 HR: 29 FCST PSN +24 HR: 26/1600 Z Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) position (+24 HR)(M) 19 Forecast of maximum surface wind (+24 HR)(M) (24 hours “DTG” given from the in Item 2); Forecast position (in degrees and minutes) of the centre of the tropical cyclone Forecast of maximum surface wind (24 hours after the “DTG” given in Item 2) Nnn[nn] or Ennn[nn] Snn[nn] Wnnn[nn] or N2912 W07530 FCST MAX WIND +24 HR: nn[n]MPS (or nn[n]KT) 20MPS FCST MAX WIND +24 HR: 20 Remarks(M ) Remarks, as necessary RMK: Free text up to 256 characters or NIL RMK: NIL 21 Expected time of issuance of next advisory (M) Expected year, month, day and time (in UTC) of issuance of next advisory NXT MSG: [BFR] nnnnnnnn/nnnnZ or NO MSG EXP NXT MSG: 2004092 5/2000Z Notes. — - 1 Verify source ↗
Used only when the message issued to indicate that a test or an exercise is taking place. When
AI-assisted research summary: This provision says the message is used only for a test or exercise, and messages containing “TEST” or “EXER” may include information not meant for operational use or may end immediately after “TEST”.
1. Used only when the message issued to indicate that a test or an exercise is taking place. When the word “TEST” or the abbreviation “EXER” is included, the message may contain information that should not be used operationally or will otherwise end immediately after the word "TEST". [Applicable 7 November 2019] - 3 Verify source ↗
In the case of CB clouds associated with a tropical cyclone covering more than one area within
AI-assisted research summary: If CB clouds associated with a tropical cyclone cover more than one area within the area of responsibility, the element may be repeated as needed.
3. In the case of CB clouds associated with a tropical cyclone covering more than one area within the area of responsibility, this element can be repeated, as necessary. - 4 Verify source ↗
The number of coordinates should be kept to a minimum and should not normally exceed
AI-assisted research summary: Advisory message templates require certain headings and formats, and the number of coordinates should be kept to a minimum and normally not exceed seven.
4. The number of coordinates should be kept to a minimum and should not normally exceed seven ExampleA2-2. Advisory message for tropical cyclones TC ADVISORY DTG: TCAC: TC: ADVISORY NR: OBS PSN: CB: 20040925/1900Z YUFO* GLORIA 2004/13 25/1800Z N2706 W07306 WI 250NM OF TC CENTRE TOP FL500 30 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) MOV: C: MAX WIND: FCST PSN +6 HR: FCST MAX WIND +6 HR: FCST PSN +12 HR: FCST MAX WIND +12 HR: FCST PSN +18 HR: FCST MAX WIND +18 HR: FCST PSN +24 HR: FCST MAX WIND +24 HR: RMK: NXT MSG: *Ficticious location NW 20KMH 965HPA 22MPS 25/2200Z N2748 W07350 22MPS 26/0400Z N2830 W07430 22MPS 26/1000Z N2852 W07500 21MPS 26/1600Z N2912 W07530 20MPS NIL 20040925/2000Z Table A2-3. Template for advisory message for space weather information Key: M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable; = = a double line indicates that the text following it should be placed on the subsequent line. Note 1.— The explanations for the abbreviations can be found in the PANS-ABC (Doc 8400). Note 2.— The spatial rsolutions ar shown in Attachment E. Note 3.— Inclusion of a colon after each element heading is mandatory. Note 4.— The numbers 1 to 14 are included only for clarity and are not part of the advisory message, as shown in the examples. 31 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) 1 2 3 4 5 6 7 Element Identification of the type of message (M) Detailed content Type of message Template(s) Examples SWX ADVISORY SWX ADVISORY Status indicator (C)1 Indicator of test or exercise STATUS: TEST or EXER STATUS: TEST EXER Time of origin (M) Year, month, day and time in UTC DTG: nnnnnnnn/nnnnZ DTG: 20161108/0100Z Name of SWXC (M) Name of SWXC SWXC:Nnnnnnnn nnnn SWXC: DONLON2 Advisory number (M) Number of advisory being replaced (C) Space weather effect and intensity (M) Year in full and unique message number Number of the previously issued advisory being replaced Effect and intensity of the space weather phenomena ADVISORY NR: nnnn/[n][n][n]n ADVISORY NR: 2016/1 NR RPLC:nnnn/[n][ n][n]n NR RPLC: 2016/1 HF COM MOD SATCOM SEV GNSS SEV HF COM MOD AND GNSS MOD RADIATION MOD SWX EFFECT: HF COM MOD or SEV or SATCOM MOD or SEV or GNSS MOD or SEV or HF COM MOD or SEV AND GNSS MOD or SEV or RADIATION3 MOD or SEV SWX EFFECT: 32 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) nn/nnnnZ OBS SWX:: 08/0100Z DAYLIGHT SIDE or DAYLIGHT HNH and/or MNH and/or SIDE EQN and/or 08/0100Z HNH EQS and/or MSH and/or HSH E18000 – HSH Wnnn(nn) or Ennn(nn) W18000 – Wnnn(nn) or Ennn(nn) 08/0100Z HNH and/or HSH W18000 – ABV FLnnnor FLnnn – W09000 ABV nnnor FL350 Nnn[nn] or Snn[nn] Wnnn[nn] orEnnn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – OBS SWX:: Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or NO SWX EXP 08/0100Z DAYLIGHT SIDE 08/0100Z HNH HSH E18000 – W18000 08/0100Z HNH HSH W18000 – W09000 ABV FL350 GN. NO.352 (Contd.) 8 Observed or expected space weather phenomena (M) 9 Forecast of the phenomena (+6 HR) (M) OBS (or FCST) SWX: FC ST S W X +6 H R: Day and time (n UTC) of observed phenomena (or forecast if phenomena have yet to occur); Horizontal extent3 (latitude bands and longitude in degrees) and/or altitude of Day and space time (in weather UTC) (6 phenomena hours from the time given in Item 8, rounded to the next full hour); Forecast extent and/or altitude of the space weather phenomena for that fixed valid time 33 nn/nn nnZ DAY LIGH T SIDE or HNH and/o r MNH and/o r EQN and/o r EQS and/o r MSH and/o r HSH Wnnn (nn) or Ennn( nn) – Wnnn (nn) or Ennn( nn) and/o r ABV FLnn n or FLnn n – nnnor Nnn[n n] or Snn[n n] Wnnn [nn] or Ennn[ nn] – Nnn[n n] or Snn[n n] Wnnn [nn] or Ennn[ nn] – Nnn[n n] or Snn[n n] Wnnn [nn] or Ennn[ nn] – [Nnn[ nn] or Snn[n n] Wnnn [nn] or Ennn[ nn] – Nnn[n n] or Snn[n n] Wnnn [nn] Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) 10 Forecast of the phenomena (+12 HR) (M) 11 Forecast of the phenomena (+18 HR) (M) FCST SWX +12 HR: nn/nnnnZ 08/1300Z DAYLIGHT SIDE or DAYLIGHT SIDE HNH and/or MNH and/or 08/1300Z HNH EQN and/or HSH W18000 – EQS and/or MSH and/or HSH W09000 ABV Wnnn(nn) or Ennn(nn) – FL350 Wnnn(nn) or Ennn(nn) 08/1300Z HNH and/or HSH E18000 – ABV FLnnn or FLnnn – nnnor W18000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or NO SWX EXP or nn/nnnnZ 08/1900Z FCST SWX NOT AVBL DAYLIGHT SIDE or DAYLIGHT SIDE +18 HR: HNH and/or MNH and/or 08/1900Z HNH EQN and/or HSH W18000 – EQS and/or MSH and/or HSH W09000 ABV Wnnn(nn) or Ennn(nn) – FL350 Wnnn(nn) or Ennn(nn) 08/1900Z HNH and/or HSH E18000 – ABV FLnnn or FLnnn – nnnor W18000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or NO SWX EXP or NOT AVBL Day and time (in UTC) (12 hours from the time given in Item 8, rounded to the next full hour). Forecast extent and/or altitude of the space weather phenomena for that fixed valid time Day and time (in UTC) (18 hours from the time given in Item 8, rounded to the next full hour). Forecast extent and/or altitude of the space weather phenomena for that fixed valid time FCST SWX +12 HR : FCST SWX +18 HR: 34 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) 12 Forecast of the phenomena (+24 HR) (M) FCST SWX +24 HR: Day and time (in UTC) (24 hours from the time given in Item 8, rounded to the next full hour). Forecast extent and/or altitude of the space weather phenomena for that fixed valid time nn/nnnnZ 09/0100Z FCST SWX DAYLIGHT SIDE or DAYLIGHT SIDE +24 HR: HNH and/or MNH and/or 09/0100Z HNH EQN and/or HSH W18000 – EQS and/or MSH and/or HSH W09000 ABV Wnnn(nn) or Ennn(nn) – FL350 Wnnn(nn) or Ennn(nn) 09/0100Z HNH and/or HSH E18000 – ABV FLnnn or FLnnn – nnnor W18000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or NO SWX EXP or NOT AVBL SWX EVENT HAS CEASED WWW.SPACEWEA THER PROVIDER.GOV NIL 13 Remarks (M) Remarks, as necessary RM K: RMK: Free text up to 256 characters or NIL 14 Next advisory (M) NXT ADVISORY: Year, month, day and time in UTC 20161108/0700Z NO FURTHER ADVISORIES NXT ADVISORY: nnnnnnnn/nnnnZ or NO FURTHER ADVISORIES or WILL BE ISSUED BY nnnnnnnn/nnnnZ Notes. — 35 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Used only when the message issued to indicate that a test or an exercise is taking place. - 1 Verify source ↗
Section 1
AI-assisted research summary: If a message includes “TEST” or “EXER,” it may contain information that should not be used operationally, or it may end immediately after the word “TEST.”
1. When the word “TEST” or the abbreviation “EXER” is included, the message may contain information that should not be used operationally or will otherwise end immediately after the word "TEST". [Applicable 7 November 2019] - 3 Verify source ↗
Section 3
AI-assisted research summary: This section gives example space weather advisory message formats for GNSS, radiation, and HF communication effects.
3. for “GNSS” and “RADIATION”. Fictitious location. One or more latitude ranges should be included in the space weather advisory information Example A2-3. Space weather advisory message (GNSS and HFCOM effects) 20161108/0100Z DONLON* 2016/2 2016/1 HF COM MOD AND GNSS MOD 08/0100Z HNH HSH E18000 – W18000 08/0700Z HNH HSH E18000 – W18000 08/1300Z HNH HSH E18000 – W18000 08/1900Z HNH HSH E18000 – W18000 09/0100Z NO SWX EXP LOW LVL GEOMAGNETIC STORMING CAUSING INCREASED AURORAL ACT AND SUBSEQUENT MOD DEGRADATION OF GNSS AND HF COM AVBL IN THE AURORAL ZONE. THIS STORMING EXP TO SUBSIDE IN THE FCST PERIOD. SEE WWW.SPACEWEATHERPROVIDER.WEB NO FURTHER ADVISORIES SWX ADVISORY DTG: SWXC: ADVISORY NR: NR RPLC: SWX EFFECT: OBS SWX: FCST SWX +6 HR: FCST SWX +12 HR: FCST SWX +18 HR: FCST SWX +24 HR RMK: NXT ADVISORY: * Ficticious location 36 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Example A2-4. Space weather advisory message (RADIATION effects) 20161108/0000Z DONLON* 2016/2 2016/1 RADIATION MOD 08/0100Z HNH HSH E18000 – W18000 ABV FL 350 08/0700Z HNH HSH E18000 – W18000 ABV FL 350 08/1300Z HNH HSH E18000 – W18000 ABV FL 350 08/1900Z HNH HSH E18000 – W18000 ABV FL 350 09/0100Z NO SWX EXP RADIATION LVL EXCEEDED 100 PCT OF BACKGROUND LVL AT FL350 AND ABV. THE CURRENT EVENT HAS PEAKED AND LVL SLW RTN TO BACKGROUND LVL. SEE WWW.SPACEWEATHERPROVIDER.WEB NO FURTHER ADVISORIES SWX ADVISORY DTG: SWXC: ADVISORY NR: NR RPLC: SWX EFFECT: FCST SWX: FCST SWX +6 HR: FCST SWX +12 HR: FCST SWX +18 HR: FCST SWX +24 HR: RMK: NXT ADVISORY: * Ficticious location Example A2-5. Space weather advisory message (HF COM effects) 37 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) SWX ADVISORY DTG: SWXC: ADVISORY NR: SWX EFFECT: OBS SWX: FCST SWX +6 HR: FCST SWX +12 HR: FCST SWX +18 HR: FCST SWX +24 HR RMK: NXT ADVISORY: * Fictitious location 20161108/0100Z DONLON* 2016/1 HF COM SEV 08/0100Z DAYLIGHT SIDE 08/0700Z DAYLIGHT SIDE 08/1900Z DAYLIGHT SIDE 09/0100Z NO SWX EXP PERIODIC HF COM ABSORPTION AND LIKELY TO CONT IN THE NEAR TERM. CMPL AND PERIODIC LOSS OF HF ON THE SUNLIT SIDE OF THE EARTH EXP. CONT HF COM DEGRADATION LIKELY OVER THE NXT 7 DAYS. SEE WWW.SPACEWEATHERPROVIDER.WEB 20161108/0700Z 38 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) ________ THIRD SCHEDULE __________ (Made under regulation 16(11)) __________ TECHNICAL SPECIFICATIONS RELATED TO METEOROLOGICAL OBSERVATIONS AND REPORTS - 1 Verify source ↗
Section 1
AI-assisted research summary: This section is titled “General Provisions Related to Meteorological Observations.”
1. GENERAL PROVISIONS RELATED TO METEOROLOGICAL OBSERVATIONS - 1
AI-assisted research summary: Meteorological instruments used at an aerodrome must be sited so they provide representative data for the area being measured.
1.1 The meteorological instruments used at an aerodrome shall be situated in such a way as to supply data which are representative of the area for which the measurements are required. Note.— Specifications concerning the siting of equipment and installations on operational areas, aimed at reducing the hazard to aircraft to a minimum, are contained in Civil Aviation( Aerodrome) regulations. Meteorological instruments at aeronautical meteorological stations shall be exposed, - 1
AI-assisted research summary: Something must be operated and maintained according to practices, procedures, and specifications promulgated by the World Meteorological Organization (WMO).
1.2 operated and maintained in accordance with the practices, procedures and specifications promulgated by the World Meteorological Organization (WMO). - 1
AI-assisted research summary: The text requires data to be representative of the area for the required observations and says aerodrome observers should be positioned as practicable, but the sentence is incomplete.
1.3 supply data which are representative of the area for which the observations are required. The observers at an aerodrome shall be located, in so far as is practicable, so as to - 1
AI-assisted research summary: Data shown to local air traffic services units must be a subset of, and shown in parallel with, the data available to the local meteorological service unit; meteorological elements must be annotated to show the locations they represent, where appropriate.
1.4 Where automated equipment forms part of an integrated semi-automatic observing system, displays of data which are made available to the local air traffic services units shall be a subset of and displayed parallel to those available in the local meteorological service unit. In those displays, each meteorological element shall be annotated to identify, as appropriate, the locations for which the element is representative. - 2 Verify source ↗
Section 2
AI-assisted research summary: This section concerns general criteria for reports related to meteorological matters.
2. REPORTS GENERAL CRITERIA RELATED TO METEOROLOGICAL - 2 Verify source ↗
1.1
AI-assisted research summary: Local routine and special reports must be issued in abbreviated plain language and follow the template in Table A3-1.
2.1.1 accordance with the template shown in TableA3-1. Local routine and special reports shall be issued in abbreviated plain language, in - 2 Verify source ↗
1.2
AI-assisted research summary: METAR and SPECI are to be issued using the prescribed code forms and the template in the table.
2.1.2 A3-2 and disseminated in the METAR and SPECI code forms prescribed by WMO. METAR and SPECI shall be issued in accordance with the template shown in Table Note.— The METAR and SPECI code forms are contained in the Manual on Codes (WMO-No. 306), Volume I.1, Part A — Alphanumeric Codes. - 2 Verify source ↗
1.3
AI-assisted research summary: METAR and SPECI must be disseminated in IWXXM GML form, in accordance with section 2.1.2.
2.1.3 dissemination of the METAR and SPECI in accordance with2.1.2. METAR and SPECI shall be disseminated in IWXXM GML form in addition to the 39 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) - 2 Verify source ↗
2 Use of CAVOK
AI-assisted research summary: CAVOK applies when, at the time of observation, visibility is 10 km or more and the lowest visibility is not reported.
2.2 Use of CAVOK When the following conditions occur simultaneously at the time of observation: a) visibility, 10 km or more, and the lowest visibility is not reported; Note 1.— In local routine and special reports, visibility refers to the value(s) to be reported in accordance with - 4 Verify source ↗
2.4.2 and 4.2.4.3; in METAR and SPECI, visibility refers to the value(s) to be reported in
AI-assisted research summary: For METAR and SPECI, visibility is reported using the values required by 4.2.4.4, and certain visibility, weather, and cloud information is replaced by the term “CAVOK”.
4.2.4.2 and 4.2.4.3; in METAR and SPECI, visibility refers to the value(s) to be reported in accordance with 4.2.4.4. Note 2.— The lowest visibility is reported in accordance with 4.2.4.4 a). b) c) no cloud of operational significance; no weather of significance to aviation as given in 4.4.2.3, 4.4.2.5 and4.4.2.6; Information on visibility, runway visual range, present weather and cloud amount, cloud type and height of cloud base shall be replaced in all meteorological reports by the term “CAVOK”. - 2 Verify source ↗
3 Criteria for issuance of local special reports and SPECI
AI-assisted research summary: Section title only: criteria for issuing local special reports and SPECI.
2.3 Criteria for issuance of local special reports and SPECI - 2 Verify source ↗
3.1
AI-assisted research summary: This provision lists the criteria to use when issuing local special reports.
2.3.1 following: The list of criteria for the issuance of local special reports shall include the a) using the aerodrome; those values which most closely correspond with the operating minima of the operators b) of the operators; those values which satisfy other local requirements of the air traffic services units and c) an increase in air temperature of 2°C or more from that given in the latest report, or an alternative threshold value as agreed between the meteorological authority, the appropriate ATS authority and the operators concerned; d) meteorological conditions in the approach and climb-out areas as given in Table A3-1; the available supplementary information concerning the occurrence of significant e) when noise abatement procedures are applied in accordance with the PANS-ATM (Doc 4444) and the variation from the mean surface wind speed (gusts) has changed by 2.5 m/s (5 kt) or more from that at the time of the latest report, the mean speed before and/or after the change being 7.5 m/s (15 kt) or more; and f) those values which constitute criteria for SPECI. - 2 Verify source ↗
3.2
AI-assisted research summary: A SPECI report must be issued when specified weather changes occur, including wind shifts, wind-speed or gust changes, certain precipitation or thunderstorm events, freezing fog, and qualifying cloud-layer changes.
2.3.2 whenever changes in accordance with the following criteria occur: Where required in accordance with Chapter 4, 4.4.2 b), SPECI shall be issued a) the latest report, the mean speed before and/or after the change being 5 m/s (10 kt) or more; when the mean surface wind direction has changed by 60° or more from that given in 40 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) b) in the latest report; when the mean surface wind speed has changed by 5m/s(10kt) or more from that given when the variation from the mean surface wind speed (gusts) has changed by 5 m/s (10 c) kt) or more from that at the time of the latest report, the mean speed before and/or after the change being 7.5m/s (15kt) or more; d) phenomena occurs: when the onset, cessation or change in intensity of any of the following weather — — — e) — — f) 1) 2) freezing precipitation moderate or heavy precipitation (including showers thereof) thunderstorm (with precipitation); when the onset or cessation of any of the following weather phenomena occurs: freezing fog thunderstorm (without precipitation); when the amount of a cloud layer below 450 m (1 500 ft) changes: from SCT or less to BKN or OVC; or from BKN or OVC to SCT or less. - 2 Verify source ↗
3.3
AI-assisted research summary: The meteorological authority must establish threshold values for when SPECI reports are issued, after consulting the appropriate ATS authority and operators.
2.3.3 whenever changes in accordance with the following criteria occur: Where required in accordance with regulation 21(2)(b), SPECI shall be issued when the wind changes through values of operational significance. The threshold values a) shall be established by the meteorological authority in consultation with the appropriate ATS authority and the operators concerned, taking into account changes in the wind which would: 1) require a change in runway(s) in use; and indicate that the runway tailwind and crosswind components have changed 2) through values representing the main operating limits for typical aircraft operating at the aerodrome; b) when the visibility is improving and changes to or passes through one or more of the following values, or when the visibility is deteriorating and passes through one or more of the following values: 1) 800, 1 500 or 3 000 m; and 2) 5 000 m, in cases where significant numbers of flights are operated in accordance with the visual flight rules; Note 1.— In local special reports, visibility refers to the value(s) to be reported in accordance with4.2.4.2 and - 4 Verify source ↗
2.4.3; in SPECI, visibility refers to the value(s) to be reported in accordance with 4.2.4.4
AI-assisted research summary: In SPECI reports, visibility means the visibility value(s) reported under 4.2.4.4, usually prevailing visibility.
4.2.4.3; in SPECI, visibility refers to the value(s) to be reported in accordance with 4.2.4.4. Note 2.— Visibility refers to “prevailing visibility” except in the case where only the lowest visibility is reported in accordance with 4.2.4.4 b). c) when the runway visual range is improving and changes to or passes through one or 41 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) 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 800m; d) phenomena occurs: when the onset, cessation or change in intensity of any of the following weather — — — e) dust storm sandstorm funnel cloud (tornado or waterspout); when the onset or cessation of any of the following weather phenomena occurs: — low drifting dust, sand or snow — — blowing dust, sand or snow squall; f) when the height of base of the lowest cloud layer of BKN or OVC extent is lifting and changes to or passes through one or more of the following values, or when the height of base of the lowest cloud layer of BKN or OVC extent is lowering and passes through one or more of the following values: 1) 30, 60, 150 or 300 m (100, 200, 500 or 1 000 ft); and 2) 450 m (1 500 ft), in cases where significant numbers of flights are operated in accordance with the visual flight rules; g) when the sky is obscured and the vertical visibility is improving and changes to or passes through one or more of the following values, or when the vertical visibility is deteriorating and passes through one or more of the following values: 30, 60, 150 or 300 m (100, 200, 500 or 1 000 ft); and h) meteorological authority and the operators concerned. any other criteria based on local aerodrome operating minima, as agreed between the Note.— Other criteria based on local aerodrome operating minima are to be considered in parallel with similar criteria for the inclusion of change groups and for the amendment of TAF developed in response to the Fifth Schedule. - 2 Verify source ↗
3.4
AI-assisted research summary: If one weather element worsens while another improves, issue a single SPECI and treat it as a deterioration report.
2.3.4 When a deterioration of one weather element is accompanied by an improvement in another element, a single SPECI shall be issued; it shall then be treated as a deterioration report. - 3 Verify source ↗
Section 3
AI-assisted research summary: This section is titled “Dissemination of Meteorological Reports.”
3. DISSEMINATION OF METEOROLOGICALREPORTS - 3 Verify source ↗
1.1
AI-assisted research summary: METAR and SPECI must be disseminated to international OPMET databanks and to centres designated under the regional air navigation agreement.
3.1.1 METAR and SPECI shall be disseminated to international OPMET databanks, and the centres designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services, in accordance with regional air navigation agreement. 42 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) - 3 Verify source ↗
1.2
AI-assisted research summary: METAR and SPECI reports must be disseminated to other aerodromes in accordance with the stated rule.
3.1.2 regional air navigation agreement. METAR and SPECI shall be disseminated to other aerodromes in accordance with - 3 Verify source ↗
1.3
AI-assisted research summary: SPECI reports showing deteriorating conditions must be disseminated immediately after the observation.
3.1.3 SPECI representing a deterioration in conditions shall be disseminated immediately after the observation. A SPECI representing a deterioration of one weather element and an improvement in another element shall be disseminated immediately after the observation. - 3 Verify source ↗
1.4
AI-assisted research summary: A SPECI report showing improved conditions may be disseminated only after the improvement has lasted 10 minutes, and it must be updated before dissemination if needed to show the conditions at the end of that 10-minute period.
3.1.4 A SPECI representing an improvement in conditions shall be disseminated only after the improvement has been maintained for 10 minutes; it shall be amended before dissemination, if necessary, to indicate the conditions prevailing at the end of that 10- minuteperiod. - 3 Verify source ↗
2.1
AI-assisted research summary: Certain information must be made available at the aerodrome, and local routine reports must be transmitted to local air traffic services units.
3.2.1 be made available to the operators and to other users at the aerodrome. Local routine reports shall be transmitted to local air traffic services units and shall - 3 Verify source ↗
2.2
AI-assisted research summary: Local special reports must be sent to local air traffic services units when the specified conditions happen, unless agreed exceptions apply.
3.2.2 Local special reports shall be transmitted to local air traffic services units as soon as the specified conditions occur. However, as agreed between the meteorological authority and the appropriate ATS authority, they need not be issued in respect of: a) any element for which there is in the local air traffic services unit a display corresponding to the one in the meteorological station, and where arrangements are in force for the use of this display to update information included in local routine and special reports; and b) use are being reported to the local air traffic services unit by an observer on the aerodrome. runway visual range, when all changes of one or more steps on the reporting scale in Local special reports shall also be made available to the operators and to other users at the aerodrome. - 4 Verify source ↗
Section 4
AI-assisted research summary: This section is about observing and reporting meteorological elements.
4. OBSERVING AND REPORTING OF METEOROLOGICALELEMENTS Introductory Note.— Selected criteria applicable to meteorological information referred to under - 4 Verify source ↗
1 to 4.8 for inclusion in aerodrome reports are given in tabular form in Table A3-0
AI-assisted research summary: Items 4.1 to 4.8 for inclusion in aerodrome reports are set out in Table A3-0.
4.1 to 4.8 for inclusion in aerodrome reports are given in tabular form in Table A3-0. - 4 Verify source ↗
1.1.1
AI-assisted research summary: Surface wind must be observed at a height of 10 ± 1 m (30 ± 3 ft) above ground.
4.1.1.1 Surface wind shall be observed at a height of 10 ± 1 m (30 ± 3 ft) above the 43 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) ground. - 4 Verify source ↗
1.1.2
AI-assisted research summary: Surface wind observations must be taken using appropriately sited sensors, with sensor placement aimed at the best practicable indication of runway and touchdown-zone conditions.
4.1.1.2 Representative surface wind observations shall be obtained by the use of sensors appropriately sited. Sensors for surface wind observations for local routine and special reports shall be sited to give the best practicable indication of conditions along the runway and touchdown zones. At aerodromes where topography or prevalent weather conditions cause significant differences in surface wind at various sections of the runway, additional sensors shall be provided. Note.— Since, in practice, the surface wind cannot be measured directly on the runway, surface wind observations for take-off and landing are expected to be the best practicable indication of the winds which an aircraft will encounter during take-off and landing. - 4 Verify source ↗
1.2.1
AI-assisted research summary: Surface wind displays must be installed in the meteorological station and matched with corresponding displays in the appropriate air traffic services units.
4.1.2.1 Surface wind displays relating to each sensor shall be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units shall relate to the same sensors, and where separate sensors are required as specified in 4.1.1.2, the displays shall be clearly marked to identify the runway and section of runway monitored by each sensor. - 4 Verify source ↗
1.2.2
AI-assisted research summary: Automated equipment must derive and display the speed for each sensor.
4.1.2.2 speed for each sensor shall be derived and displayed by automated equipment. The mean values of, and significant variations in, the surface wind direction and - 4 Verify source ↗
1.3.1
AI-assisted research summary: It sets the averaging period for surface wind observations, including different periods for different report types and an exception when wind changes abruptly.
4.1.3.1 The averaging period for surface wind observations shall be: (a) services units; and 2 minutes for local routine and special reports and for wind displays in air traffic (b) 10 minutes for METAR and SPECI, except that when the 10-minute period includes a marked discontinuity in the wind direction and/or speed, only data occurring after the discontinuity shall be used for obtaining mean values; hence, the time interval in these circumstances shall be correspondingly reduced. Note.— A marked discontinuity occurs when there is an abrupt and sustained change in wind direction of 30° or more, with a wind speed of 5 m/s (10 kt) before or after the change, or a change in wind speed of 5 m/s (10 kt) or more, lasting at least 2 minutes. The averaging period for measuring variations from the mean wind speed (gusts) - 4 Verify source ↗
1.3.2
AI-assisted research summary: This provision sets a 3-second timing requirement for certain local reports and wind displays in air traffic services units.
4.1.3.2 reported in accordance with 4.1.5.2 c) shall be 3 seconds for local routine reports, local special reports, METAR, SPECI and wind displays used for depicting variations from the mean wind speed (gusts) in airt traffic services units. - 4 Verify source ↗
1.4
AI-assisted research summary: Reported wind direction and speed, and variations from the mean surface wind, must meet the operationally desirable accuracy of measurement in the First Schedule.
4.1.4 Accuracy of measurement The reported direction and speed of the mean surface wind, as well as variations from the mean surface wind, shall meet the operationally desirable accuracy of measurement as given in the First Schedule. 44 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.)
Part
Schedule.
- 4 Verify source ↗
1.5.1
AI-assisted research summary: In certain weather reports, surface wind direction and speed must be reported in fixed steps, and values that do not fit the scale must be rounded to the nearest step.
4.1.5.1 In local routine reports, local special reports, METAR and SPECI, the surface wind direction and speed shall be reported in steps of 10 degrees true and 1 metre per second (or 1 knot), respectively. Any observed value which does not fit the reporting scale in use shall be rounded to the nearest step in the scale. - 4 Verify source ↗
1.5.2
AI-assisted research summary: In local routine reports, local special reports, METAR, and SPECI, the wind speed measurement units must be shown, and a special reporting rule applies when total wind-direction variation is 60° or more.
4.1.5.2 In local routine reports, local special reports, METAR and SPECI: (a) the units of measurement used for the wind speed shall be indicated; (b) follows, if the total variation is 60° or more: variations from the mean wind direction during the past 10 minutes shall be reported as when the total variation is 60° or more and less than 180° and the wind speed is 1) - 1 Verify source ↗
5 m/s (3 kt) or more, such directional variations shall be reported as the two extreme directions
AI-assisted research summary: Wind direction and gust reporting must follow specified thresholds and reporting formats.
1.5 m/s (3 kt) or more, such directional variations shall be reported as the two extreme directions between which the surface wind has varied; when the total variation is 60° or more and less than 180° and the wind speed is 2) less than 1.5 m/s (3 kt), the wind direction shall be reported as variable with no mean wind direction; or 3) variable with no mean wind direction; when the total variation is 180° or more, the wind direction shall be reported as (c) reported when the maximum wind speed exceeds the mean speed by: variations from the mean wind speed (gusts) during the past 10 minutes shall be 1) procedures are applied in accordance with the PANS-ATM (ICAO Doc 4444); or - 2 Verify source ↗
5 m/s (5 kt) or more in local routine and special reports when noise abatement
AI-assisted research summary: Wind speed reporting must use different thresholds and reporting wording depending on the situation, including calm conditions, higher wind speeds, and marked discontinuities.
2.5 m/s (5 kt) or more in local routine and special reports when noise abatement 2) (d) 5 m/s (10 kt) or more otherwise; when a wind speed of less than 0.5 m/s (1 kt) is reported, it shall be indicated as calm; (e) than 49m/s (99kt); and when a wind speed of 50m/s(100kt) or more is reported, it shall be indicated to be more when the 10-minute period includes a marked discontinuity in the wind direction and/or (f) speed, only variations from the mean wind direction and mean wind speed occurring since the discontinuity shall be reported. Note.— See note under 4.1.3.1. - 4 Verify source ↗
1.5.3
AI-assisted research summary: Local routine and special reports must identify where wind values are representative and report runway-specific wind information and wind-direction variation details.
4.1.5.3 In local routine and special reports: (a) locations for which these values are representative shall be indicated; if the surface wind is observed from more than one location along the runway, the 45 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) when there is more than one runway in use and the surface wind related to these (b) runways is observed, the available wind values for each runway shall be given, and the runways to which the values refer shall be reported; when variations from the mean wind direction are reported in accordance with 4.1.5.2 (c) b) 2), the two extreme directions between which the surface wind has varied shall be reported; and when variations from the mean wind speed (gusts) are reported in accordance with (d) - 4 Verify source ↗
1.5.2 c), they shall be reported as the maximum and minimum values of the wind speed
AI-assisted research summary: It says the wind speed must be reported as its maximum and minimum values attained.
4.1.5.2 c), they shall be reported as the maximum and minimum values of the wind speed attained. - 4 Verify source ↗
1.5.4
AI-assisted research summary: In METAR and SPECI reports, when wind-speed variations (gusts) are reported under 4.1.5.2(c), the maximum wind speed attained must be reported.
4.1.5.4 In METAR and SPECI, when variations from the mean winds peed (gusts) are reported in accordance with 4.1.5.2 c), the maximum value of the wind speed attained shall be reported. - 4 Verify source ↗
2.1.1
AI-assisted research summary: When instrumented systems are used to measure visibility, the measurement must be taken at about 2.5 m (7.5 ft) above the runway.
4.2.1.1 When instrumented systems are used for the measurement of visibility, the visibility shall be measured at a height of approximately 2.5 m (7.5 ft) above the runway. When instrumented systems are used for the measurement of visibility, - 4 Verify source ↗
2.1.2
AI-assisted research summary: Visibility observations must be obtained using appropriately sited sensors.
4.2.1.2 representative visibility observations shall be obtained by the use of sensors appropriately sited. Sensors for visibility observations for local routine and special reports shall be sited to give the best practicable indications of visibility along the runway and touchdown zone. - 4 Verify source ↗
2.2
AI-assisted research summary: When instrumented systems are used to measure visibility, the related displays must be placed in the meteorological station and mirrored in the relevant air traffic services units.
4.2.2 Displays When instrumented systems are used for the measurement of visibility, visibility displays relating to each sensor shall be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units shall relate to the same sensors, and where separate sensors are required as specified in 4.2.1, the displays shall be clearly marked to identify the area, e.g. runway and section of runway, monitored by each sensor. - 4 Verify source ↗
2.3
AI-assisted research summary: Visibility measurements from instrumented systems must be updated at least every 60 seconds, and averaging periods must be 1 minute for some reports/displays and 10 minutes for METAR and SPECI, with a special rule when visibility changes abruptly.
4.2.3 Averaging When instrumented systems are used for the measurement of visibility, their output shall be updated at least every 60 seconds to permit provision of current representative values. The averaging period shall be: (a) services units; and 1minute for local routine and special reports and for visibility displays in air traffic 46 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) (b) 10 minutes for METAR and SPECI, except that when the 10-minute period immediately preceding the observation includes a marked discontinuity in the visibility, only those values occurring after the discontinuity shall be used for obtaining mean values. Note.— A marked discontinuity occurs when there is an abrupt and sustained change in visibility, lasting at least 2 minutes, which reaches or passes through criteria for the issuance of SPECI reports given in2.3. - 4 Verify source ↗
2.4
AI-assisted research summary: This provision fragment concerns how visibility is reported in local routine reports, local special reports, METAR, and SPECI.
4.2.4 Reporting In local routine reports, local special reports, METAR and SPECI, the visibility - 4 Verify source ↗
2.4.1
AI-assisted research summary: Visibility must be reported in fixed steps based on how far it is: 50 m below 800 m, 100 m from 800 m to under 5 km, 1 km from 5 km to under 10 km, and 10 km at 10 km or more, unless CAVOK applies.
4.2.4.1 shall be reported in steps of 50 m when the visibility is less than 800 m; in steps of 100 m, when it is 800 m or more but less than 5 km; in kilometre steps, when the visibility is 5 km or more but less than 10 km; and it shall be given as 10 km when the visibility is 10 km or more, except when the conditions for the use of CAVOK apply. Any observed value which does not fit the reporting scale in use shall be rounded down to the nearest lower step in the scale. Note.— Specifications concerning the use of CAVOK are given in 2.2. - 4 Verify source ↗
2.4.2
AI-assisted research summary: Local routine and special reports must report runway visibility.
4.2.4.2 together with the units of measurement used to indicate visibility. In local routine and special reports, visibility along the runway(s) shall be reported - 4 Verify source ↗
2.4.3
AI-assisted research summary: Visibility reporting rules require values for different runway locations to be reported in a set order, and in METAR and SPECI visibility must be reported as prevailing visibility.
4.2.4.3 measurement of visibility: In local routine and special reports, when instrumented systems are used for the if the visibility is observed from more than one location along the runway as specified (a) in regulation 28, the values representative of the touchdown zone shall be reported first, followed, as necessary, by the values representative of the mid-point and stop-end of the runway, and the locations for which these values are representative shall be indicated; and when there is more than one runway in use and the visibility is observed related to these (b) runways, the available visibility values for each runway shall be reported, and the runways to which the values refer shall be indicated. In METAR and SPECI, visibility shall be reported as prevailing visibility, as - 4 Verify source ↗
2.4.4
AI-assisted research summary: When visibility differs by direction, the lowest visibility must be reported in certain cases, and sometimes its direction should also be reported.
4.2.4.4 defined in regulation 3. When the visibility is not the same in different directions and (a) when the lowest visibility is different from the prevailing visibility, and 1) less than 1 500 m or 2) less than 50 per cent of the prevailing visibility and less than 5 000 m; the lowest visibility observed shall also be reported and, when possible, its general direction in relation to the aerodrome reference point indicated by reference to one of the eight points of the compass. If the lowest visibility is observed in more than one direction, then the most operationally significant direction shall be reported; and (b) determined, only the lowest visibility shall be reported, with no indication of direction. when the visibility is fluctuating rapidly, and the prevailing visibility cannot be - 4 Verify source ↗
3 Runway visual range
AI-assisted research summary: Section heading for runway visual range.
4.3 Runway visual range 47 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) - 4 Verify source ↗
3.1.1
AI-assisted research summary: Runway visual range must be assessed from about 2.5 m above the runway for instrumented systems, or from about 5 m above the runway when assessed by a human observer.
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 instrumented systems or assessed at a height of approximately 5 m (15 ft) above the runway by a human observer. - 4 Verify source ↗
3.1.2
AI-assisted research summary: Runway visual range measurements must use specified observation locations and distances from the runway threshold and centre line.
4.3.1.2 Runway visual range shall be assessed at a lateral distance from the runway centre line of not more than 120m.The site for observations to be representative of the touchdown zone shall be located about 300m along the runway from the threshold. The sites for observations to be representative of the mid-point and stop-end of the runway shall be located at 1000 to1500m along the runway from the threshold and at about 300m from the other end of the runway. The exact position of these sites and, if necessary, additional sites shall be decided after considering aeronautical, meteorological, and climatological factors such as long runways, swamps, and other fog-prone areas. - 4 Verify source ↗
3.2 Instrumented systems
AI-assisted research summary: Runway visual range instruments should be checked before selection, and a forward-scatter meter’s calibration must be traceable and verifiable to a verified transmissometer standard.
4.3.2 Instrumented systems Note.— Since accuracy can vary from one instrument design to another, performance characteristics are to be checked before selecting an instrument for assessing runway visual range. The calibration of a forward-scatter meter has to be traceable and verifiable to a transmissometer standard, the accuracy of which has been verified over the intended operational range. Guidance on the use of transmissometers and forward-scatter meters in instrumented runway visual range systems is given in the Manual of Runway Visual Range Observing and Reporting Practices (ICAO Doc9328). Instrumented systems based on transmissometers, or forward-scatter meters shall - 4 Verify source ↗
3.2.1
AI-assisted research summary: The text says runway visual range is to be assessed for Category II and III instrument approach and landing operations using instrumented systems such as transmissometers or forward-scatter meters.
4.3.2.1 be used to assess runway visual range on runways intended for Category II and III instrument approach and landing operations. Instrumented systems based on transmissometers, or forward-scatter meters shall - 4 Verify source ↗
3.2.2
AI-assisted research summary: It says something is to be used to assess runway visual range for runways intended for Category I instrument approach and landing operations.
4.3.2.2 be used to assess runway visual range on runways intended for Category I instrument approach and landing operations. - 4 Verify source ↗
3.3.1
AI-assisted research summary: If runway visual range is determined by instrumented systems, the required displays must be placed in the meteorological station and in the relevant air traffic services units.
4.3.3.1 Where runway visual range is determined by instrumented systems, one display or more, if required, shall be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units shall be related to the same sensors, and where separate sensors are required as specified in 4.3.1.2, the displays shall be clearly marked to identify the runway and section of runway monitored by each sensor. - 4 Verify source ↗
3.3.2
AI-assisted research summary: If runway visual range is measured by human observers, it must be reported to the local air traffic services unit when the value changes, unless another cited rule applies.
4.3.3.2 Where runway visual range is determined by human observers, runway visual range shall be reported to the appropriate local air traffic services units, whenever there is a change in the value to be reported in accordance with the reporting scale (except where the provisions of 3.2.2 a) or b) apply). The transmission of such reports shall normally be completed within15 seconds after the termination of the observation. 48 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) - 4 Verify source ↗
3.4
AI-assisted research summary: Instrumented runway visual range systems must update their output at least every 60 seconds, and runway visual range averaging must use the stated averaging periods, with a special rule where there is a marked discontinuity.
4.3.4 Averaging Where instrumented systems are used for the assessment of runway visual range, their output shall be updated at least every 60 seconds to permit the provision of current, representative values. The averaging period for runway visual range values shall be: (a) traffic services units; and 1minute for local routine and special reports and for runway visual range displays in air (b) 10 minutes for METAR and SPECI, except that when the 10-minute period immediately preceding the observation includes a marked discontinuity in runway visual range values, only those values occurring after the discontinuity shall be used for obtaining mean values. Note.— A marked discontinuity occurs when there is an abrupt and sustained change in runway visual range, lasting at least 2 minutes, which reaches or passes through the values 800, 550, 300 and 175 m. - 4 Verify source ↗
3.5
AI-assisted research summary: For runway visual range calculations, use the applicable runway’s light intensity rules, including special treatment when lights are on at more than 3% of maximum intensity and when reporting METAR or SPECI.
4.3.5 Runway light intensity When instrumented systems are used for the assessment of runway visual range, computations shall be made separately for each available runway. For local routine and special reports, the light intensity to be used for the computation shall be: (a) of the maximum light intensity available, the light intensity actually in use on that runway; for a runway with the lights switched on and the light intensity of more than 3 per cent (b) for a runway with the lights switched on and the light intensity of 3 per cent or less of the maximum light intensity available, the optimum light intensity that would be appropriate for operational use in the prevailing conditions; and for a runway with lights switched off (or at the lowest setting pending the resumption of (c) operations), the optimum lightintensitythatwouldbeappropriateforoperationaluseintheprevailingconditions. In METAR and SPECI, the runway visual range shall be based on the maximum light intensity available on the runway. Note.— Guidance on the conversion of instrumented readings into runway visual range is given in table A3-0. Commented [H1]: o be provided as guidance material - 4 Verify source ↗
3.6.1
AI-assisted research summary: Runway visual range in routine and special reports must be reported in set steps, depending on the distance range, and values that do not fit the scale must be rounded down.
4.3.6.1 In local routine reports, local special reports, METAR and SPECI, the runway visual range shall be reported in steps of 25 m when the runway visual range is less than 400 m; in steps of 50 m when it is between 400 m and 800 m; and in steps of 100 m when the runway visual range is more than 800 m. Any observed value which does not fit the reporting scale in use shall be rounded down to the nearest lower step in the scale. 49 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Fifty metres shall be considered the lower limit and 2 000 metres the upper limit - 4 Verify source ↗
3.6.2
AI-assisted research summary: For runway visual range outside the stated limits, local routine reports, local special reports, METAR and SPECI must only say it is below 50 m or above 2 000 m.
4.3.6.2 for runway visual range. Outside of these limits, local routine reports, local special reports, METAR and SPECI shall merely indicate that the runway visual range is less than 50 m or more than 2 000m. - 4 Verify source ↗
3.6.3
AI-assisted research summary: If runway visual range is above or below what the system can determine, reports must use the specified abbreviations and then state the applicable maximum or minimum value.
4.3.6.3 In local routine reports, local special reports, METAR and SPECI: (a) when runway visual range is above the maximum value that can be determined by the system in use, it shall be reported using the abbreviation “ABV” in local routine and special reports and the abbreviation “P” in METAR and SPECI, followed by the maximum value that can be determined by the system; and (b) when the runway visual range is below the minimum value that can be determined by the system in use, it shall be reported using the abbreviation “BLW” in local routine and special reports and the abbreviation “M” in METAR and SPECI, followed by the minimum value that can be determined by the system. - 4 Verify source ↗
3.6.4
AI-assisted research summary: Local routine and special reports must include measurement units, and runway visual range values must be reported with location details as specified.
4.3.6.4 In local routine and special reports: (a) the units of measurement used shall be included. (b) touchdown zone, it shall be included without any indication of location; if runway visual range is observed from only one location along the runway, i.e., the (c) if the runway visual range is observed from more than one location along the runway, the value representative of the touchdown zone shall be reported first, followed by the values representative of the mid-point and stop-end and the locations for which these values are representative shall be indicated; and (d) when there is more than one runway in use, the available runway visual range values for each runway shall be reported and the runways to which the values refer shall be indicated. - 4 Verify source ↗
3.6.5
AI-assisted research summary: For METAR and SPECI reports, runway location and visual range details must be included, with touchdown-zone values used and runway references shown.
4.3.6.5 In METAR and SPECI: (a) of location on the runway shall be included; and only the value representative of the touchdown zone shall be reported and no indication where there is more than one runway available for landing, touchdown zone runway (b) visual range values shall be included for all such runways, up to a maximum of four, and the runways to which the values refer shall be indicated. - 4 Verify source ↗
3.6.6
AI-assisted research summary: For METAR and SPECI, if instrumented systems are used to assess runway visual range, the 10-minute variation before the observation must be included when it shows a distinct tendency; use U for upward, D for downward, N for no distinct tendency, and no abbreviation if no tendency indication is available.
4.3.6.6 In METAR and SPECI when instrumented systems are used for the assessment of runway visual range, the variations in runway visual range during the 10-minute period immediately preceding the observation shall be included if the runway visual range values during the 10-minute period have shown a distinct tendency, such that the mean during the first 5 minutes varies by 100 m or more from the mean during the second 5 minutes of the period. When the variation of the runway visual range values shows an upward or downward tendency, this shall be indicated by the abbreviation “U” or “D”, respectively. In circumstances when actual fluctuations during the 10-minute period show no distinct tendency, this shall be indicated using the abbreviation “N”. When indications of tendency are not available, no abbreviations shall be included. 50 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) - 4 Verify source ↗
4.1 Siting
AI-assisted research summary: This provision heading concerns siting for instrumented systems used to observe present weather phenomena.
4.4.1 Siting When instrumented systems are used for observing present weather phenomena listed under - 4 Verify source ↗
4.2.3 and4.4.2.4, representative information shall be obtained by the use of sensors
AI-assisted research summary: Representative information must be obtained using sensors that are appropriately sited.
4.4.2.3 and4.4.2.4, representative information shall be obtained by the use of sensors appropriately sited. - 4 Verify source ↗
4.2.1
AI-assisted research summary: Observed present weather phenomena are to be reported in local routine and special reports by type, characteristics, and intensity, where appropriate; the sentence then continues for METAR and SPECI but is cut off.
4.4.2.1 In local routine and special reports, observed present weather phenomena shall be reported in terms of type and characteristics and qualified with respect to intensity, as appropriate. In METAR and SPECI, observed present weather phenomena shall be reported in - 4 Verify source ↗
4.2.2
AI-assisted research summary: This provision refers to terms that are defined by type and characteristics and adjusted for intensity or proximity to the aerodrome, as appropriate.
4.4.2.2 terms of type and characteristics and qualified with respect to intensity or proximity to the aerodrome, as appropriate. - 4 Verify source ↗
4.2.3
AI-assisted research summary: Local routine reports, local special reports, METAR and SPECI must report specified present weather phenomena using the relevant abbreviations and criteria.
4.4.2.3 In local routine reports, local special reports, METAR and SPECI, the following types of present weather phenomena shall be reported, using the irrespective abbreviations and relevant criteria, as appropriate: Precipitation (a) Drizzle Rain Snow Snow grains Ice pellets Hail — Reported when diameter of largest hailstones is 5 mm or more. Small hail and/or snow pellets — Reported when diameter of largest hailstones is less than 5mm. (b) Obscuration (hydrometeors) DZ RA SN SG PL GR GS FG Reported when visibility is less than 1 000 m, except when qualified by “MI”, Fog — “BC”, “PR” or “VC” (see 4.4.2.6 and4.4.2.8). Mist — BR Reported when visibility is at least 1 000 m but not more than 5 000m. Obscuration (lithometeors) (c) — The following should be used only when the obscuration consists predominantly of lithometeors, and the visibility is 5 000 m or less except “SA” when qualified by “DR” (see - 4 Verify source ↗
4.2.6) and volcanic ash
AI-assisted research summary: This provision lists weather and visibility phenomena, including dust, haze, smoke, volcanic ash, and several storm or whirl-type events.
4.4.2.6) and volcanic ash. Sand SA 51 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Dust(widespread) Haze Smoke Volcanic ash Other phenomena (d) Dust/sand whirls (dust devils) Squall Funnel cloud (tornado or waterspout) Dust storm Sandstorm DU HZ FU VA PO SQ FC DS SS - 4 Verify source ↗
4.2.4
AI-assisted research summary: In certain aviation weather reports, use the abbreviation UP when precipitation is unidentified by the automatic observing system.
4.4.2.4 In automated local routine reports, local special reports, METAR and SPECI, in addition to the precipitation types listed under 4.4.2.3 a), the abbreviation UP shall be used for unidentified precipitation when the type of precipitation cannot be identified by the automatic observing system. In local routine reports, local special reports, METAR and SPECI, the following - 4 Verify source ↗
4.2.5
AI-assisted research summary: Present weather phenomena must be reported using the relevant abbreviations and criteria, including special handling for thunderstorm reporting.
4.4.2.5 characteristics of present weather phenomena, as necessary, shall be reported, using their respective abbreviations and relevant criteria, as appropriate: Thunderstorm — Used to report a thunderstorm with precipitation in accordance with the templates shown in Tables A3-1 and A3-2. When thunder is heard or lightning is detected at the aerodrome during the 10-minute period preceding the time of observation but no precipitation is observed at the aerodrome, the abbreviation “TS” shall be used without qualification. TS Freezing — phenomena in accordance with the templates shown in Tables A3-1and A3-2. FZ Supercooled water droplets or precipitation, used with types of present weather Note.— At aerodromes with human observers, lightning detection equipment may supplement human observations. For aerodromes with automatic observing systems, guidance on the use of lightning detection equipment intended for thunderstorm reporting is given in the Manual on Automatic Meteorological Observing Systems at Aerodromes (ICAO Doc 9837). In local routine reports, local special reports, METAR and SPECI, the following - 4 Verify source ↗
4.2.6
AI-assisted research summary: Present weather phenomena should be reported using the relevant abbreviations and criteria; showers are reported as specified in the referenced tables.
4.4.2.6 characteristics of present weather phenomena, as necessary, shall be reported, using their respective abbreviations and relevant criteria, as appropriate: Shower — Used to report showers in accordance with the templates shown in Tables A3-1 and A3- - 2 Verify source ↗
Showers observed in the vicinity of the aerodrome (see 4.4.2.8) should be reported as “VCSH”
AI-assisted research summary: Showers near the aerodrome should be reported as “VCSH” without saying whether the precipitation is light or heavy.
2. Showers observed in the vicinity of the aerodrome (see 4.4.2.8) should be reported as “VCSH” without qualification regarding type or intensity of precipitation. SH Blowing — Used in accordance with the templates shown in Tables A3-1 and A3-2 with types of present weather phenomena raised by the wind to a height of 2 m (6 ft) or more above the ground. BL Low drifting — Used in accordance with the templates shown in Tables A3-1 and A3-2 with types of DR 52 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) present weather phenomena raised by the wind to less than 2 m (6 ft) above ground level. Shallow — Patches — Less than 2 m (6 ft) above ground level. Fog patches randomly covering the aerodrome. MI BC Partial — PR A substantial part of the aerodrome covered by fog while the remainder is clear. In automated local routine reports, local special reports, METAR and SPECI, - 4 Verify source ↗
4.2.7
AI-assisted research summary: If showers (SH) cannot be determined using a method that accounts for convective cloud, the precipitation must not be described as SH.
4.4.2.7 when showers (SH) referred to in 4.4.2.6 cannot be determined based upon a method that takes account of the presence of convective cloud, the precipitation shall not be characterized by SH. In local routine reports, local special reports, METAR and SPECI, the relevant - 4 Verify source ↗
4.2.8
AI-assisted research summary: Weather reports must use the specified intensity or vicinity codes for present weather phenomena.
4.4.2.8 intensity or, as appropriate, the proximity to the aerodrome of the reported present weather phenomena shall be indicated as follows: (local routine and special reports) (METAR and SPECI) Light Moderate Heavy FBL MOD HVY — (no indication) + Used with types of present weather phenomena in accordance with the templates shown in Tables A3-1 and A3-2. Light intensity should be indicated only for precipitation. Vicinity VC — Between approximately 8 and 16 km of the aerodrome reference point and used only in METAR and SPECI with present weather in accordance with the template shown in Table A3-2 when not reported under 4.4.2.5 and 4.4.2.6. - 4 Verify source ↗
4.2.9
AI-assisted research summary: In certain weather reports, the text says to use one or more, up to three, present weather abbreviations, but the provision is cut off.
4.4.2.9 In local routine reports, local special reports, METAR and SPECI: (a) one or more, up to a maximum of three, of the present weather abbreviations given in - 4 Verify source ↗
4.2.3 and 4.4.2.4 shall be used, as necessary, together with an indication, where appropriate, of
AI-assisted research summary: Weather reports must use the specified coded groups and, where appropriate, show characteristics and intensity/proximity to give a complete description of present weather affecting flight operations.
4.4.2.3 and 4.4.2.4 shall be used, as necessary, together with an indication, where appropriate, of the characteristics given in 4.4.2.5. and 4.4.2.6 and intensity or proximity to the aerodrome given in 4.4.2.8, so as to convey a complete description of the present weather of significance to flight operations; (b) respectively by the characteristics and the type of weather phenomena; and the indication of intensity or proximity, as appropriate, shall be reported first followed (c) where two different types of weather are observed, they shall be reported in two separate groups, where the intensity or proximity indicator refers to the weather phenomenon which follows the indicator. However, different types of precipitation occurring at the time of observation shall be reported as one single group with the dominant type of precipitation reported 53 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) first and preceded by only one intensity qualifier which refers to the intensity of the total precipitation. - 4 Verify source ↗
4.2.10
AI-assisted research summary: When the automatic observing system cannot observe present weather because of a temporary system or sensor failure, present weather is replaced by “//”.
4.4.2.10 present weather shall be replaced by “//” when the present weather cannot be observed by the automatic observing system due to a temporary failure of the system/sensor. In automated local routine reports, local special reports, METAR and SPECI, the - 4 Verify source ↗
5.1
AI-assisted research summary: Cloud measurements must use sensors sited to give representative observations, and for certain aerodromes the sensors should be placed to best indicate cloud conditions at the runway threshold.
4.5.1 Clouds Siting When instrumented systems are used for the measurement of the cloud amount and the height of cloud base, representative observations shall be obtained by the use of sensors appropriately sited. For local routine and special reports, in the case of aerodromes with precision approach runways, sensors for cloud amount and height of cloud base shall be sited to give the best practicable indications of the cloud amount and height of cloud base at the threshold of the runway in use. For that purpose, a sensor shall be installed at a distance of less than 1 200 m (4 000 ft) before the landing threshold. - 4 Verify source ↗
5.2
AI-assisted research summary: Cloud base height displays must be placed in the meteorological station and matched with corresponding displays in the relevant air traffic services units.
4.5.2 Display When automated equipment is used for the measurement of the height of cloud base, height of cloud base display(s) shall be located in the meteorological station with corresponding display(s) in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units shall relate to the same sensor, and where separate sensors are required as specified in 4.5.1, the displays shall clearly identify the area monitored by each sensor. - 4 Verify source ↗
5.3
AI-assisted research summary: Cloud-base height is to be reported above aerodrome elevation, with special reporting reference for certain precision approach runways and offshore structures.
4.5.3 Reference level The height of cloud base shall be reported above aerodrome elevation. When a precision approach runway is in use which has a threshold elevation 15 m (50 ft) or more below the aerodrome elevation, local arrangements shall be made in order that the height of cloud bases reported to arriving aircraft shall refer to the threshold elevation. In the case of reports from offshore structures, the height of cloud base shall be given above mean sea level. - 4 Verify source ↗
5.4.1
AI-assisted research summary: Cloud base must be reported in 30 m (100 ft) steps up to 3,000 m (10,000 ft).
4.5.4.1 cloud base shall be reported in steps of 30 m (100 ft) up to 3 000 m (10 000ft). In local routine reports, local special reports, METAR and SPECI, the height of - 4 Verify source ↗
5.4.2
AI-assisted research summary: At aerodromes with low-visibility approach and landing procedures, local routine and special reports must report cloud base height and vertical visibility in specified step sizes.
4.5.4.2 At aerodromes where low-visibility procedures are established for approach and landing, as agreed between the meteorological authority and the appropriate ATS authority, in local routine and special reports the height of cloud base 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 the vertical visibility in steps of 15 m (50 ft) up to and including 90 m (300 ft) and in steps of 30 m (100 ft) between 90 m (300 ft) and 600 m (2000 ft). 54 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) - 4 Verify source ↗
5.4.3
AI-assisted research summary: Weather reports must use specified cloud and visibility reporting abbreviations and formats.
4.5.4.3 In local routine reports, local special reports, METAR and SPECI: (a) to 4 oktas), “BKN” (5 to 7 oktas) or “OVC” (8oktas); cloud amount shall be reported using the abbreviations “FEW” (1 to 2 oktas), “SCT” (3 (b) “TCU”, respectively; cumulonimbus clouds and towering cumulus clouds shall be indicated as “CB” and (c) the vertical visibility shall be reported in steps of 30m (100ft) up to 600m (2000ft); (d) and the abbreviation “CAVOK” is not appropriate, the abbreviation “NSC” shall be used; if there are no clouds of operational significance and no restriction on vertical visibility when several layers or masses of cloud of operational significance are observed, their (e) amount and height of cloud base shall be reported in increasing order of the height of cloud base, and in accordance with the following criteria: 1) or OVC as appropriate; the lowest layer or mass, regardless of amount to be reported as FEW, SCT, BKN 2) OVC as appropriate; the next layer or mass, covering more than 2/8 to be reported as SCT, BKN or 3) OVC as appropriate; and the next higher layer or mass, covering more than 4/8 to be reported as BKN or 4) reported in1) to 3); cumulonimbus and/or towering cumulus clouds, whenever observed and not (f) cloud base, or cloud fragments, shall be reported; and when the cloud base is diffuse or ragged or fluctuating rapidly, the minimum height of (g) when an individual layer (mass) of cloud is composed of cumulonimbus and towering cumulus clouds with a common cloud base, the type of cloud shall be reported as cumulonimbus only. Note. — Towering cumulus indicates cumulus congestus clouds of great vertical extent. - 4 Verify source ↗
5.4.4
AI-assisted research summary: Reporting values must be rounded down to the nearest lower step in the scale.
4.5.4.4 reporting scale in use shall be rounded down to the nearest lower step in the scale. Any observed value in 4.5.4.1, 4.5.4.2 and 4.5.4.3 c) which does not fit the - 4 Verify source ↗
5.4.5
AI-assisted research summary: Reports must show the units used for cloud-base height and vertical visibility, and where multiple runways are in use, the reported cloud-base values must be tied to the runway they refer to.
4.5.4.5 In local routine and special reports: (a) be indicated; and The units of measurement used for the height of cloud base and vertical visibility shall when there is more than one runway in use and the heights of cloud bases are observed (b) by instruments for these runways, the available heights of cloud bases for each runway shall be reported and the runways to which the values refer shall be indicated. - 4 Verify source ↗
5.4.6
AI-assisted research summary: For automated local routine reports, local special reports, METAR and SPECI, certain cloud and visibility fields must be replaced with placeholders when they cannot be observed or determined automatically.
4.5.4.6 In automated local routine reports, local special reports, METAR and SPECI: 55 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) a) type in each cloud group shall be replaced by “///”; when the cloud type cannot be observed by the automatic observing system, the cloud b) using the abbreviation “NCD”; when no clouds are detected by the automatic observing system, it shall be indicated by c) when cumulonimbus clouds or towering cumulus clouds are detected by the automatic observing system and the cloud amount and/or the height of cloud base cannot be observed, the cloud amount and/or the height of cloud base shall be replaced by “///”; and the vertical visibility shall be replaced by “///” when the sky is obscured, and the value d) of the vertical visibility cannot be determined by the automatic observing system due to a temporary failure of the system/sensor. - 4 Verify source ↗
6.1
AI-assisted research summary: When automated equipment is used to measure air temperature and dew-point temperature, the displays must be placed in the meteorological station and mirrored in the relevant air traffic services units.
4.6.1 Air temperature and dew-point temperature Display When automated equipment is used for the measurement of air temperature and dew-point temperature, air temperature and dew-point temperature displays shall be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units shall relate to the same sensors. - 4 Verify source ↗
6.2.1
AI-assisted research summary: Air temperature and dew-point temperature in local routine reports, local special reports, METAR and SPECI must be reported in whole degrees Celsius, with values rounded to the nearest whole degree and .5 rounded up.
4.6.2.1 In local routine reports, local special reports, METAR and SPECI, the air temperature and the dew-point temperature shall be reported in steps of whole degrees Celsius. Any observed value which does not fit the reporting scale in use shall be rounded to the nearest whole degree Celsius, with observed values involving 0.5° rounded up to the next higher whole degree Celsius. - 4 Verify source ↗
6.2.2
AI-assisted research summary: Temperatures below 0°C must be identified in the listed report types.
4.6.2.2 below 0°C shall be identified. In local routine reports, local special reports, METAR and SPECI, a temperature - 4 Verify source ↗
7.1 Display
AI-assisted research summary: If automated equipment is used to measure atmospheric pressure, the text refers to QNH and additional requirements that follow if required in accordance with the provision, but the excerpt is incomplete.
4.7.1 Display When automated equipment is used for the measurement of atmospheric pressure, QNH and, if required in accordance with - 4 Verify source ↗
7.3.2 b), QFE displays relating to the barometer shall be located in the meteorological station
AI-assisted research summary: QFE displays relating to the barometer must be located in the meteorological station, with corresponding displays in the appropriate air traffic services units.
4.7.3.2 b), QFE displays relating to the barometer shall be located in the meteorological station with corresponding displays in the appropriate air traffic services units. When QFE values, as 56 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) specified in - 4 Verify source ↗
7.3.2 d),the displays shall be clearly marked to identify the runway to which the QFE value
AI-assisted research summary: Displays must be clearly marked so the runway for the displayed QFE value can be identified.
4.7.3.2 d),the displays shall be clearly marked to identify the runway to which the QFE value displayed refers. - 4 Verify source ↗
7.2
AI-assisted research summary: QFE is computed using the aerodrome elevation, and for certain precision approach runways it must use the relevant threshold elevation if required.
4.7.2 Reference level The reference level for the computation of QFE shall be the aerodrome elevation. For non- precision approach runways, the thresholds of which are 2 m (7 ft) or more below the aerodrome elevation, and for precision approach runways, the QFE, if required, shall refer to the relevant threshold elevation. - 4 Verify source ↗
7.3.1
AI-assisted research summary: QNH and QFE must be computed in tenths of hectopascals and reported in whole hectopascal steps using four digits; values outside the reporting scale must be rounded down.
4.7.3.1 For local routine reports, local special reports, METAR and SPECI, QNH and QFE shall be computed in tenths of hectopascals and reported therein in steps of whole hectopascals, using four digits. Any observed value which does not fit the reporting scale in use shall be rounded down to the nearest lower whole hectopascal. - 4 Verify source ↗
7.3.2
AI-assisted research summary: Local routine and special reports must include QNH, and may also include QFE when required by users or agreed; the units used and the relevant runway information must also be stated.
4.7.3.2 In local routine and special reports: (a) QNH shall be included; (b) authority, the appropriate ATS authority and the operators concerned, on a regular basis; QFE shall be included if required by users or as agreed between the meteorological (c) the units of measurement used for QNH and QFE values shall be included; and (d) runway shall be reported and the runways to which the values refer shall be indicated. if QFE values are required for more than one runway, the required QFE values for each - 4 Verify source ↗
7.3.3
AI-assisted research summary: In METAR and SPECI reports, only QNH values may be included.
4.7.3.3 In METAR and SPECI, only QNH values shall be included. - 4 Verify source ↗
8.1.1
AI-assisted research summary: Local routine reports, local special reports, METAR and SPECI should include up to three recent weather phenomena from the listed set; the meteorological authority may agree not to provide recent weather information when SPECI are issued.
4.8.1.1 In local routine reports, local special reports, METAR and SPECI, the following recent weather phenomena, i.e. weather phenomena observed at the aerodrome during the period since the last issued routine report or last hour, whichever is the shorter, but not at the time of observation, shall be reported, up to a maximum of three groups, in accordance with the templates shown in Tables A3-1and A3-2, in the supplementary information: — — — — — freezing precipitation moderate or heavy precipitation (including showers thereof) blowing snow dust storm, sandstorm thunderstorm 57 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) — — funnel cloud (tornado or waterspout) volcanic ash Note.— The meteorological authority, in consultation with users, may agree not to provide recent weather information where SPECI are issued. - 4 Verify source ↗
8.1.2
AI-assisted research summary: Certain significant weather conditions or combinations must be reported in supplementary information, with the condition’s location indicated and extra detail added in abbreviated plain language when needed.
4.8.1.2 conditions, or combinations thereof, shall be reported in supplementary information: In local routine and special reports, the following significant meteorological cumulonimbus clouds thunderstorm moderate or severe turbulence wind shear hail severe squall line moderate or severe icing freezing precipitation — — — TURB, SEVTURB — — — — SEVICE — FZRA — — — — severe mountain waves duststorm, sandstorm blowing snow funnel cloud (tornado or waterspout) CB TS MOD WS GR SEVSQL MOD ICE, FZDZ, SEV MTW DS, SS BLSN FC The location of the condition shall be indicated. Where necessary, additional information shall be included using abbreviated plain language. In automated local routine reports, local special reports, METAR and SPECI, in - 4 Verify source ↗
8.1.3
AI-assisted research summary: Recent unknown precipitation must be reported using the Table A3-2 template when automatic observing systems cannot identify the precipitation type.
4.8.1.3 addition to the recent weather phenomena listed under 4.8.1.1, recent unknown precipitation shall be reported in accordance with the templateshowninTableA3-2 when the type of precipitation cannot be identified by the automatic observing system. Note.— The meteorological authority, in consultation with users, may agree not to provide recent weather information where SPECI are issued. - 4 Verify source ↗
8.1.4
AI-assisted research summary: In METAR and SPECI, wind shear shall be included when local circumstances warrant it.
4.8.1.4 wind shear shall be added. In METAR and SPECI, where local circumstances so warrant, information on Note.— The local circumstances referred to in 4.8.1.4 include, but are not necessarily limited to, wind shear of a non- transitory nature such as might be associated with low-level temperature inversions or local topography. - 4 Verify source ↗
8.1.5
AI-assisted research summary: METAR and SPECI reports must include specified supplementary information about sea conditions and runway state.
4.8.1.5 supplementary information, in accordance with regional air navigation agreement: In METAR and SPECI, the following information shall be included in the (a) information on sea-surface temperature, and the state of the sea or the significant wave height from aeronautical meteorological stations established on offshore structures in support of helicopter operations; and (b) information on the state of the runway provided by the appropriate airport authority. 58 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Note 1.— The state of the sea is specified in the Manual on Codes (WMO-No. 306), Volume I.1, Part A — Alphanumeric Codes, Code Table 3700. Note 2.— The state of the runway is specified in the Manual on Codes (WMO-No. 306), Volume I.1, Part A — Alphanumeric Codes, Code Tables 0366, 0519, 0919 and 1079. Notes.—
Part
Part A — Alphanumeric Codes, Code Table 3700.
- 1 Verify source ↗
Considered for the past 10 minutes (exception: if the 10-minute period includes a marked
AI-assisted research summary: For runway visual range criteria, use the past 10 minutes of data, unless that 10-minute period includes a marked discontinuity; in that case, use only data after the discontinuity.
1. Considered for the past 10 minutes (exception: if the 10-minute period includes a marked discontinuity (i.e., runway visual range changes or passes 175, 300, 550 or 800 m, lasting ≥ 2 minutes), only data after the discontinuity to be used). A simple diagrammatic convention is used to illustrate those parts of the 10-minute period prior to the observation relevant to runway visual range criteria, i.e. AB, BC and AC. - 2 Verify source ↗
Layer composed of CB and TCU with a common base should be reported as “CB”
AI-assisted research summary: A layer made up of CB and TCU with a common base should be reported as “CB”.
2. Layer composed of CB and TCU with a common base should be reported as “CB”. - 3 Verify source ↗
Consideredforthepast10 minutes (exception: if the10-minute period includes a marked
AI-assisted research summary: Use the past 10 minutes of data, unless that period includes a marked discontinuity; in that case, use only data after the discontinuity.
3. Consideredforthepast10 minutes (exception: if the10-minute period includes a marked discontinuity (i.e., The direction changes ≥30° with a speed ≥ 5 m/s or the speed changes ≥ 5 m/s lasting ≥ 2 minutes), only data after the discontinuity to be used). - 4 Verify source ↗
If several directions, the most operationally significant direction used
AI-assisted research summary: If there are several directions, use the one that is most operationally significant.
4. If several directions, the most operationally significant direction used. - 5 Verify source ↗
Let R 5(AB)= 5-minute mean runway visual range value during period AB and R 5 (BC) = 5
AI-assisted research summary: This section defines R 5(AB) and R 5(BC) as 5-minute mean runway visual range values for periods AB and BC.
5. Let R 5(AB)= 5-minute mean runway visual range value during period AB and R 5 (BC) = 5- minute mean runway visual range value during period BC. - 6 Verify source ↗
CB (cumulonimbus) and TCU (towering cumulus=cumulus congestus of great vertical extent)
AI-assisted research summary: This section defines CB as cumulonimbus and TCU as towering cumulus/cumulus congestus, unless they are already indicated as one of the other layers.
6. CB (cumulonimbus) and TCU (towering cumulus=cumulus congestus of great vertical extent) if not already indicated as one of the other layers. - 7 Verify source ↗
Time averaging, for mean values and, if applicable, referring period for extreme values,
AI-assisted research summary: This section labels time averaging for mean values and, where applicable, the referring period for extreme values in the upper left-hand corner.
7. Time averaging, for mean values and, if applicable, referring period for extreme values, indicated in the upper left-hand corner. - 8 Verify source ↗
According to the Manual on Codes (WMO-No. 306), Volume I.1, Part A — Alphanumeric
AI-assisted research summary: It is recommended that wind measuring systems be designed so peak gusts represent a three-second average.
8. According to the Manual on Codes (WMO-No. 306), Volume I.1, Part A — Alphanumeric Codes, paragraph 15.5.5, it is recommended that the wind measuringsystemsshouldbesuchthatpeakgustsshouldrepresentathree-secondaverage”. - 10 Verify source ↗
QFE is to be included if required. Reference elevation for QFE should be aerodrome elevation
AI-assisted research summary: If required, QFE must be included. For reference elevation, use aerodrome elevation except for precision approach runways and certain non-precision approach runways.
10. QFE is to be included if required. Reference elevation for QFE should be aerodrome elevation except for precision approach runways, and non-precision approach runways with threshold ≥2m(7ft) below or above aerodrome elevation, where the reference level should be there levant threshold elevation. - 12 Verify source ↗
Also, sea-surface temperature, and state of the sea or the significant wave height from
AI-assisted research summary: This provision refers to sea-surface temperature, sea state, or significant wave height from offshore structures, in line with a regional air navigation agreement.
12. Also, sea-surface temperature, and state of the sea or the significant wave height from offshore structures in accordance with regional air navigation agreement. - 13 Verify source ↗
Report if RVR and/or VIS<1500m, limits for assessments 50 and 2000m
AI-assisted research summary: Report when RVR and/or visibility is below 1500 m.
13. Report if RVR and/or VIS<1500m, limits for assessments 50 and 2000m. - 14 Verify source ↗
For landing at aerodromes with precision approach runways and with the threshold elevation
AI-assisted research summary: For certain aerodrome landings, use the threshold elevation as the reference when the runway has a precision approach and the threshold is at least 15 m below the aerodrome elevation.
14. For landing at aerodromes with precision approach runways and with the threshold elevation ≥ 15 m below the aerodrome elevation, the threshold elevation to be used as a reference. - 15 Verify source ↗
Measured in 0.1hPa
AI-assisted research summary: This section gives the key for Table A3-1 and explains that M means mandatory, C means conditional, and O means optional inclusion.
15. Measured in 0.1hPa. Table A3-1. Template for the local routine (MET REPORT) and local special (SPECIAL) reports M = Key: C = O = inclusion mandatory, part of every message; inclusion conditional, dependent on meteorological conditions; inclusion optional. Note 1.— The ranges and resolutions for the numerical elements included in the local routine and 59 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) special reports are shown in Table A3-4 of this Schedule. Note 2.— The explanations for the abbreviations can be found in the Procedures for Air Navigation Services — ICAO Abbreviations and Codes (PANS-ABC, Doc 8400). 60 Civil Aviation (Meteorological Service For International Air Navigation) (Amendment) GN. NO.352 (Contd.) Dodoma 11th May, 2023 MAKAME M. MBARAWA, Minister for Works and Transport 61
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The Civil Aviation (Meteorological Service for International Air Navigation) (Amendment) Regulations, 2023
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