Originally Posted by
DaveReidUK
Only to the very lazy.
For as long as I can remember, Leeds-Bradford/Yeadon has been LBA/EGNM. Unless ATC were in the habit of inventing their own designators, which seems unlikely.
The Trident suggestion re G-AVYD covers the Yankee Delta oddity.
How far back to four letter ICAO codes go?
East Midlands IATA designator was CDD as late as 1975.