IATA codes and ICAO codes designate aerodromes. They are not related and have some differences.
With more than 40,000 airports existing in the world, it becomes necessary to have an identification system that serves to unambiguously name each airport, differentiating it from the rest. To do this, IATA codes and ICAO aerodrome identification codes are used, which, despite designating the same airport, are unrelated to each other and have some differences:
The IATA code it is perhaps the best-known airport code and the one most used by the average passenger, as it is the one that appears on airline tickets, boarding passes, luggage tags or airport information screens, and they are decided by the International Air Transport Association (IATA).
Los códigos IATA son códigos de tres letras que identifican aeropuertos, así como compañías aéreas. three-letter code This usually relates to the city or region served by the airport, or the name of the airfield that existed before the airport was created, but it doesn't necessarily have to contain geographical information about it. Examples include the codes for Málaga Airport (AGP), Charles de Gaulle in Paris (CDG), or London's main airport, Heathrow (LHR).
As they only contain three letters, the possible combinations are limited and consequently IATA codes are not unique in some cases, with the same code being able to designate two different airports. As a result of the uniqueness in designation required by the aeronautical system, ICAO codes exist.
The ICAO codes are appointed by the International Civil Aviation Organisation (ICAO) and are used by the more “aeronautical” professionals in the air transport sector (controllers, pilots, etc.), so they are generally less known by the average passenger.
They consist of a four-letter code and its use by more specialised personnel is due to its uniqueness (there are no codes that designate more than one airport) and because they contain geographical information about the aerodrome due to their structure. Let's see what it looks like:
first letter of an airport's ICAO code designates the geographical zone according to ICAO where is it located.
The second letter of the ICAO code indicates the country where it is located, within the geographical area indicated by the first letter.
The third and fourth letters of the code already serve to identify the airport Specifically.
As with everything, there are slight exceptions, as Canada, the United States and Australia are considered ICAO zones in themselves due to their extensive size, so the last three letters of the code are enough to define the aerodrome.
Taking the same examples we referred to earlier, in the case of Málaga airport, the code is LEMG, in the case of Paris Charles de Gaulle, it's LFPG, while London-Heathrow's is EGLL.
