Primarily for general aviation discussion, but other aviation topics are also welcome.
Muzzlehatch wrote:also on

That's a treasure trove of weird identifiers I have never seen before.

Rob P
chevvron wrote:USA has the best system.
Assigned the prefix 'K', they simply added the IATA 3 letter code to get the ICAO location indicator.

Analogously in Canada: C prefixed to the Yxx IATA designator, eg Toronto International is YYZ/CYYZ

Other quirks are:

EGYP is RAF Mount Pleasant in the Falklands. Reportedly, it was Mrs Thatcher who insisted it had an 'EG..' designator, althought the older Port Stanley airfield was and remains SFAL

There were so few locations requiring designators in the Aldergrove patch that initials could be used; thus EGAA Aldergrove, EGAE Eglinton, EGAN Nutts Corner ..

Locations with indicators do not have to be airports, only places with AFTN connexions. Thus Bletchley Park had one when, after the war, it became the GPO Telecomms training centre, including for AFTN teleprinter (and Morse!) operators

Although K is the designated first letter for USA, (for "domestic (entertainment)" radio broadcasting stations as well as for aerodromes) I believe I have seen very extensive lists of US aerodromes"officially" designated by 4 characters not starting with a K - many starting instead with some digits? I believe what I had seen was based on FAA documents???

Germany seems to use ETxx (rather than EDxx) fro military aerodromes.
Muzzlehatch wrote:I'd always assumed that the X designator was for unlicensed airfields such as XPLO for Plocton and X6MU for Glenforsa.
Is this not the case?
Just curious.

No . 'X' has never been an 'official' designator in the UK.
The code for airfields not assigned a location indicator was 'ZZZZ' and any messages such as flight plans had to have the name of the airfield in the 'RMKs' section.
Any other system used by 3rd parties was totally unofficial.
As an update to this thread....

The reply from the CAA has suggested that any airfield applying for an ICAO 4 letter identifier should also form part of the Aeronautical Fixed Service (AFS) via AFTN.

Anyone able to give details (or point me in the direction of documentation) of what is required of an airfield to be part of the AFS?

JonathanB wrote:Probably a (paid) airfield account on AFPEx?

Is it possible for a non-ATSU AFPEx subscriber to have a non-ATSU identifier? It seems that Skydemon has some sort of capture corridor for addressing flight plans. Receipt of spurious flight plans can be a bit of a nuisance.