ICAO 4 letter code

From Scramble - The Aviation Magazine

The ICAO (International Civil Aviation Organization) code is a unique 4-letter code used to identify airports/airbases throughout the world. This codes are called location indicator. The ICAO has subdivided the Earth into several regions. The first letter describes the region in which the airport is located. The second letter stands for the country the airbase is located in. The third letter normally describes the aviation authority or organization responsible for the airfield. The fourth letter stands for the aerodrome itself and normally is the first letter of the name of the airbase.

There are of course a lot of exceptions. In the continental USA/Canada codes normally consist of a 'K'/'C' followed by the airport's 3-letter IATA code.

Germany has two second letter. ED.. for German civil airports and ET.. for German military air bases. Some more information for German location indicator:

ETN. = GAF (North)

ETS. = GAF (South)

ETH. = GAM

ETM. = GNY

ETA. = USAFE

ETE. = USAREUR

ETI. = USAREUR

ETO. = USAREUR

ETU. = RAF Germany/AAC

ETR. = SAR command

EDD. = International airport

In Switzerland military airfields can be recognized by 'M' as third letter e.g. LSMD=Duebendorf.

In Austria military airfields can be recognized by 'X' as third letter e.g. LOXL=Hoersching.

A complete list of ICAO codes can be found at: Scramble ICAO Database