International Civil Aviation Organization airport code
The ICAO (
/ˌaɪˌkeɪˈoʊ/, "I-K-O") airport code or location indicator is a four-character alphanumeric code designating each airport around the world. These codes are defined by the International Civil Aviation Organization, and published in ICAO Document 7910: Location Indicators.
The ICAO codes are used by air traffic control and airline operations such as flight planning. They are not the same as the IATA codes encountered by the general public, which are used for airline timetables, reservations, and baggage handling. IATA codes are usually derived from the name of the airport or the city it serves, while ICAO codes are distributed by region and country. For example, travellers who use London's Heathrow Airport will most likely be familiar with its IATA code: LHR. They are less likely, however, to be familiar with the ICAO code: EGLL.
ICAO codes are also used to identify other locations such as weather stations, International Flight Service Stations or Area Control Centers, whether or not they are located at airports.
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[edit] History
World War II caused a great increase in international flying which sparked concerns over safety and communication. After the war, under the auspices of the UN, regions were defined for the purposes of controlling traffic and making airport identification simple and clear. The regions were given the name FIR (Flight Information Region).
Since the Allied military had done so much of the long-range wartime flying, English became the primary language of international air traffic control. Allied influence also had a hand in some of the code selections. There was also the influence of existing national radio station codes. For example, stations in Canada were already starting with "C", so it seemed logical to begin Canadian airport identifiers that way, such as CYQM for Moncton. Most other identifiers have less recognizable phonetic connection.
Europe was going to be "E", but there were too many locations for only one starting letter. So "E" became mostly northern Europe, with the second letter defining further; EGxx for Great Britain, EDxx for Deutschland, etc. "L" became lower Europe, such as LFxx for France, although France could be thought of as both northern and southern.
The United States had a peculiar situation in that there were already two letters being used to begin radio station identifiers. "W" (from Westinghouse) for stations east of the Mississippi, and "K" for those west. The K was selected for ICAO codes. FIR and ICAO regions do not always use the same boundaries, but they are sometimes close.
[edit] Structure
Unlike the IATA codes, the ICAO codes have a regional structure (they are broken up by 'sections' of the world), are not duplicated, and are comprehensive. In general, the first letter is allocated by continent and represents a country or group of countries within that continent. The second letter generally represents a country within that region, and the remaining two are used to identify each airport. The exception to this rule is larger countries that have single-letter country codes, where the remaining three letters identify the airport. In either case, ICAO codes provide geographical context unlike IATA codes. Using the earlier example as Heathrow airport, if one knows that the ICAO code for Heathrow is EGLL, then one can deduce that the airport EGNH is somewhere in the UK (it is Blackpool International Airport). On the other hand, knowing that the IATA code for Heathrow is LHR does not enable one to deduce the location of the airport LHV with any greater certainty (it is William T. Piper Memorial Airport in Lock Haven, Pennsylvania in the United States).
The letters I, J and X are not currently used as the first letter of any ICAO identifier. Q is reserved for international radiocommunications and other non-geographical special uses (see Q code).
In the contiguous United States and Canada, most, but not all, airports have been assigned three-letter IATA codes which are the same as their ICAO code without the leading K or C. e.g., YYC and CYYC (Calgary International Airport, Calgary, Alberta), IAD and KIAD (Washington Dulles International Airport, Chantilly, Virginia). These codes are not to be confused with radio or television call signs, even though both countries use four-letter call signs starting with those letters. However, because Alaska, Hawaii and United States territories have their own 2-letter ICAO prefix, the situation there is similar to other smaller countries and the ICAO code of their airports is typically different from its corresponding 3-letter FAA/IATA identifier. For example, Hilo International Airport (PHTO vs ITO) and Juneau International Airport (PAJN vs JNU).
In region L (Southern Europe), all available 2-letter prefixes have been exhausted and thus no additional countries can be added.
ZZZZ is a special code which is used when no ICAO code exists for the airport and is normally used in flight plans.
A list of airports, sorted by ICAO code, is available below.
[edit] Prefixes
[edit] See also
- Airspace class
- Class A airport
- Geocode
- IATA airport code
- ICAO airline designators - A list of codes
- List of airports by IATA code
- List of airports by ICAO code
[edit] References
[edit] External links
- ICAO On-line Publications Purchasing (official site)
- International Civil Aviation Organization (official site)
- ICAO airport codes worldwide, by country
- Airport IATA/ICAO Designator / Code Database Search (from Aviation Codes Central Web Site - Regular Updates)
- "Airport ABCs: An Explanation of Airport Identifier Codes". Air Line Pilot. Air Line Pilots Association. December, 1994. http://www.skygod.com/asstd/abc.html.
