"Steven P. McNicoll" wrote:

"Jeff Saylor" wrote in message
...

Here's another interesting case, Drummond (Montana) Airport lost
its three letter identifier, DRU (or KDRU) recently. It is now M26.
It will be interesting to see where KDRU pops up next, I don't
know of many cases where an airport lost its 3 letter id.


Three-letter identifiers are assigned to navaids; to airports with a manned
air traffic control facility or navigational aid within airport boundary; to
airports that receive scheduled route air carrier or military airlift service,
and to airports designated by the U.S. Customs Service as Airports of Entry.



I believe airports with weather reporting capability also qualify; many airports
that do not meet the qualifications above received all letters after their new
ASOS/AWOS was comissioned. On a related note, a bunch of VORs that had the same
3 letter ID as airports that they were near had their IDs changed a number of
years ago. For example the Williamsport (Pa) VOR had its ID changed from IPT
to FQM. I've wondered if the letters FQM stand for anything but as far as I can
tell it's just a random identifier. The VOR is a distance away from IPT (KIPT)
the airport, and sits atop a mountain ridge. Apparently some pilots flew to the
mountain instead of the airport.

On the other hand MHT VOR is 4.8 miles away from KMHT (Manchester NH) airport
and they share the same identifier.

This appears to violate 7350.7N 1-2-5
1-2-5 Duplication
a. At the same location, the same identifier may be assigned to one
navigational aid (which must be located within the airport boundary), to the
airport, to a manned air traffic control facility, and to an aviation weather
station on the airport. With certain restrictions, variations of the airport
identifier may be assigned also to landing systems.


DRU VOR is close by, but it's not within the airport boundary, so DRU should never have been the identifier for Drummond Airport. Apparently
somebody finally caught the error.

7350.7N 1-2-4 doesn't make it clear that this is ground for changing the
identifier that has been assigned, although it is probably safe to assume that
if the VOR could no longer share its ID with the airport than this airport was
less important.

1-2-4 Permanence.
Established three-letter identifiers are considered permanent and will not be
changed without strong and documented justification, primarily concerning air
safety. Other than three-letter identifiers may be changed when the status of a
landing facility changes, e.g. private-use to public-use, etc.