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What does the expression (For VOR/ILS/MLS, give VAR) in the table mean? Because the VAR (magnetic variation) value is not given in the table. The table image was taken from the AIP Turkey document for Adana LTAF airport.

enter image description here

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    $\begingroup$ I checked it now, but I think it is not related to what you said because, in the ENR 4.1 section of the AIP, there is only information about Adana VOR that I have seen before. But thanks anyway. $\endgroup$
    – pilot162
    Sep 11, 2023 at 15:59

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In short: According to ICAO Annex 15, declination should be provided in this column for certain navaids. The mention "give VAR" is part of the template used, and originally found in the ICAO template (actually this template contains "give declination").

This information is not systematically provided in AIPs over the world.


ICAO SARPS

ICAO SARPS regarding AIP are found in Annex 15 AIS. Its appendix 1 describes the information to be provided in section AD 2.19 of the AIP:

AD 2.19 Radio navigation and landing aids
Detailed description of radio navigation and landing aids associated with the instrument approach and the terminal area procedures at the aerodrome, including:

  1. type of aids, magnetic variation to the nearest degree, as appropriate, and type of supported operation for ILS/MLS, basic GNSS, SBAS and GBAS,
    and for VOR/ILS/MLS station declination to the nearest degree used for technical line-up of the aid;

(This wording is confusing, variation and declination are strictly equivalent.)

ICAO specimen AIP

ICAO provides a specimen AIP (also part of Doc 8126). In this template for the sections AD 2 and AD 3, there are tables with standard column headers:

enter image description here

The mention "give declination" is already included. Turkey has customized the specimen and used the synonym "var", more familiar to the aeronautical community.

Obviously they do not provide systematically the declination as expected. Declination appears in some AIPs, and not in other. Randomly: UK/EGLL (yes), Korea/RKJK (no), Slovenia/LJPZ (yes), Bahrain/OBBS (yes), France/LFPG (no).

Implication of missing information

There is no practical consequence of not providing the declination of a navaid, as long as we are considering human interaction. Crew work using magnetic bearings only.

However for navigation computers this information is of prime importance, since they work using the true north and need to know the individual declination of the navaids in order, e.g. to continuously determine a RNAV position from VOR/DME intersection.

Indeed computers are loaded with a navigation database containing the information (ARINC 424 format or similar).

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  • $\begingroup$ Thank you for your explanation, if they are not going to give such information, I don't understand why they are stating it. It can be confusing when things aren't clear. Like the lack of information here. Anyway, I understood what the template meant, thank you again. $\endgroup$
    – pilot162
    Sep 12, 2023 at 17:19
  • $\begingroup$ Yes, it's confusing. Normally this exception to the SARPS should be mentioned in GEN 1.7 of the AIP, but it isn't. $\endgroup$
    – mins
    Sep 12, 2023 at 17:45

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