Changes in airport identifiers

Some time ago one of the local airports here changed its ID from Q99
to E16. Anyone has any clue as to why would such a change occur? The
airport has no weather station, the new ID also has digits in it. ...

Are there any rules or guidelines out there specifying how to assign
IDs to airports?

Happy Holidays

- Tom

On Tue, 26 Dec 2006 19:41:43 +0000 (UTC),
(Paul Tomblin) wrote:

In a previous article, Matt Whiting said:
Is anyone aware of a source for changes in airport identifiers? I flew
into Hilton Head twice years ago and the first time I listed the ID as
49J and the second time as HXD. The first flight was in 1994 and the

As others have already mentioned, this is due to the need for weather
reporting stations to have ICAO-compatible identifiers. The ICAO codes
are 4 letters long, and start with a country code, and cannot have
non-alphabetic characters in them (ie. no numbers). It is FAA practice to
give airports in the continental US an FAA code that is just the ICAO code
with the country prefix (K) stropped off if they have an ICAO code, so
when an airport that has an FAA identifier that has digits in it gets
weather, it changes identifier to match its new ICAO code.

Unfortunately, when you're talking about FAA airports outside of the lower
48, like Alaska, Hawaii, Puerto Rico, or other US protectorates, the
mapping between FAA code and ICAO code is much less easy. I've never
found a good source of mappings between ICAO and FAA codes except in the
DAFIF file, and that's gone the way of the Dodo bird.