Originally Posted by Jenbel
Could this have been left to local aviation authorities to decide how to code the aerodromes?
Every ICAO member country submits their list of aerodromes to ICAO, presumably with a preferred code for them.
If I'm not mistaken, all Scottish civil aerodromes have a local designator beginning with P so EDI = EGPH, GLA = EGPF, ABZ = EGPD, PIK = EGPK, etc... Scottish military aerodromes have a local designator beginnign with Q so Lossiemouth = EGQS, Macrihanish = EGQJ, etc...
I'm sure there is a local logic behind each country too, but thats it as a far as the ICAO rules go.