ATIS
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ATIS
Question: in the US, the reported wind on ATIS is in magnetic degrees, as oppose to true degrees in a metar or taf. Is this true of all countries? What is the ICAO standard?
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Join Date: Apr 2007
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ICAO Standard
ICAO Standard:
Annex 3 — Meteorological Service for International Air Navigation
4.3 Routine observations and reports
.
.
.
Note.— Meteorological information used in ATIS (voice-
ATIS and D-ATIS) is to be extracted from the local routine
report, in accordance with Annex 11, 4.3.6.1 g).
.
.
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4.6 Observing and reporting meteorological elements
4.6.1 Surface wind
4.6.1.1 The mean direction and the mean speed of the
surface wind shall be measured, as well as significant variations
of the wind direction and speed, and reported in degrees
true and kilometres per hour (or knots), respectively.
...
Annex 11 — Air Traffic Services
4.3.6.1 g) the meteorological information shall be extracted from
the local meteorological routine or special report.
Happy Easter
Annex 3 — Meteorological Service for International Air Navigation
4.3 Routine observations and reports
.
.
.
Note.— Meteorological information used in ATIS (voice-
ATIS and D-ATIS) is to be extracted from the local routine
report, in accordance with Annex 11, 4.3.6.1 g).
.
.
.
4.6 Observing and reporting meteorological elements
4.6.1 Surface wind
4.6.1.1 The mean direction and the mean speed of the
surface wind shall be measured, as well as significant variations
of the wind direction and speed, and reported in degrees
true and kilometres per hour (or knots), respectively.
...
Annex 11 — Air Traffic Services
4.3.6.1 g) the meteorological information shall be extracted from
the local meteorological routine or special report.
Happy Easter
Join Date: Aug 2003
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What has a METAR or a TAF got to do with a particular runway? Meterological sevices work in True. How can they use anything else? High level winds can cross areas of rapidly changing variation. Magnetic is something that is (or used to be!) required for navigation, not for forecasting the weather.Simply think of all Met products, including TAFs and METARS, as being produced by a meteorologist, who does not know anything about variation. ATIS and winds given from the tower are an ATC product with variation applied, as the navigation element is relevant.
It is immediately obvious that this is the correct system when operating in parts of the world with 20 or 30 degrees variation. If everyone had modern naviagtion equipment, then we could make True the primary reference in all circumstances!
It is immediately obvious that this is the correct system when operating in parts of the world with 20 or 30 degrees variation. If everyone had modern naviagtion equipment, then we could make True the primary reference in all circumstances!
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ATIS wind is usually MAG!
To the best of my knowledge ATIS wind is always reported in degrees magnetic as that's what runway headings are based on.
As an aside though.... just for information... on the good old Airbus, if you stick a wind on the PERF APPR page (the box assumes this figure is MAG) you can check this because after having done this if you then select the DESCENT WINDS from the F-PLN page you'll see the GRND level wind now displayed as a TRUE wind with the appropriate VARIATION correction removed. (Similar deal here if you were to insert the TRUE GRND level wind, the box will apply VARIATION and display the MAG wind in the PERF APPR page)
Cheers!
As an aside though.... just for information... on the good old Airbus, if you stick a wind on the PERF APPR page (the box assumes this figure is MAG) you can check this because after having done this if you then select the DESCENT WINDS from the F-PLN page you'll see the GRND level wind now displayed as a TRUE wind with the appropriate VARIATION correction removed. (Similar deal here if you were to insert the TRUE GRND level wind, the box will apply VARIATION and display the MAG wind in the PERF APPR page)
Cheers!
