The Intriguing Logic Behind Airport Designation Codes

Airport designation codes, also known as IATA location identifiers, are three-letter geocode designations for airports and metropolitan areas worldwide. The International Air Transport Association (IATA) governs the assignment of these codes, which are used in aviation and logistics to identify airports. ICAO codes, defined by the International Civil Aviation Organization, are four-character alphanumeric codes that differ from IATA codes and are used by air traffic control for flight planning and airline operations. The determination of airport designation codes can vary, with some codes named after the airport itself or its former name, while others are derived from the airport's unofficial name or the city it serves.

Airport Designation Codes Characteristics and Values Table

IATA 3-letter codes

The International Air Transport Association (IATA) uses 3-letter codes, also known as IATA location identifiers, IATA station codes, or location identifiers, to designate airports and metropolitan areas worldwide. These codes are defined by the IATA and are published semi-annually in the IATA Airline Coding Directory. The IATA provides codes for airport handling entities and certain railway stations.

The IATA 3-letter codes are used in aviation and logistics to identify airports. For example, JFK is the code for New York's John F. Kennedy Airport. These codes are also prominently displayed on baggage tags attached at airport check-in desks.

In large metropolitan areas, airport codes are often named after the airport itself, rather than the city it serves. For instance, Chicago's O'Hare International Airport is coded ORD for its former name, Orchard Field. Another example is Jakarta (JKT) – Soekarno–Hatta (CGK), where the code CGK is derived from Cengkareng, the district in which the airport is located.

Some cities with multiple airports have codes derived from the name of the airport itself. For example, New York's John F. Kennedy Airport is coded JFK, and Baltimore/Washington International Airport is coded BWI. Additionally, some airport codes come from their former or unofficial names, such as Orlando International Airport's MCO (formerly McCoy Air Force Base) and Kahului Airport's OGG (named after local aviation pioneer Jimmy Hogg).

It is important to note that IATA 3-letter codes should not be confused with the FAA identifiers of US airports or ICAO codes. While most FAA identifiers match the corresponding IATA codes, some do not, such as Saipan, with an FAA identifier of GSN and an IATA code of SPN.

ICAO 4-character alphanumeric codes

The ICAO airport code is a four-character alphanumeric code used to identify airports worldwide, as defined by the International Civil Aviation Organization. ICAO codes are used by air traffic control for flight planning and airline operations. They are distinct from IATA codes, which are used for reservations and baggage.

ICAO codes are classified geographically by region or country. In Europe, for instance, codes are split into "Exxx" for northern Europe and "Lxxx" for southern Europe. Some exceptions exist to the regional structure for political or administrative reasons. For example, RAF Mount Pleasant in the Falkland Islands has the ICAO code EGYP, as if it were in the United Kingdom. In contrast, the nearby civilian Port Stanley Airport has the code SFAL, consistent with South America.

In certain countries, the second letter of the ICAO code is linked to the airport's FIR. In Australia, for instance, the second letter usually corresponds to the FIR. However, Sydney's FIR has been non-existent since the introduction of TAAATS. In the United States and Canada, some ICAO codes are simply copies of their three-letter IATA codes, with a geographical prefix added. For example, Edmonton International Airport has the codes YEG and CYEG, while Washington Dulles International Airport has the codes IAD and KIAD.

Codes based on airport names

Airport codes are three-letter geocode designations, defined by the International Air Transport Association (IATA), for airports and metropolitan areas worldwide. These codes are used on baggage tags, in reservations, and by air traffic control.

In large metropolitan areas, airport codes are often derived from the airport's name, rather than the name of the city it serves. For example, Chicago's O'Hare International Airport is coded ORD, which comes from its original name, Orchard Field. Similarly, Jakarta's Soekarno–Hatta airport is coded CGK, named after the Cengkareng district where it is located.

Some airport codes are derived from the airport's former name, like Orlando International Airport's MCO, which stands for McCoy Air Force Base. In rarer cases, the code comes from the airport's unofficial name, such as Kahului Airport's OGG, which is named after the local aviation pioneer, Jimmy Hogg.

When a new airport replaces an old one, the new airport may retain the old airport's code, even if the code no longer corresponds with the city's name. For instance, Nashville International Airport, built in 1987, still uses the code BNA, which originally designated Berry Field, the city's original airport built in 1936.

In Canada, most large airports have codes that begin with the letter "Y". This dates back to when Canadian transcontinental railroads were built, and each station was assigned a two-letter Morse code. When the Canadian government established airports, they used the existing railway codes, adding a "Y" to indicate the presence of a weather station.

Codes based on airport locations

Airport codes are often determined by the airport's location. An IATA airport code is a three-letter geocode that designates airports and metropolitan areas worldwide, as defined by the International Air Transport Association (IATA). These codes are used prominently on baggage tags attached at airport check-in desks.

In large metropolitan areas, airport codes are usually named after the airport itself, rather than the city it serves. For instance, Buenos Aires (BUE) – Ezeiza (EZE) is named after the suburb in Ezeiza Partido where the airport is located, while Aeroparque Jorge Newbery (AEP) is in the city proper. Similarly, Chicago (CHI) – O'Hare (ORD) is named after Orchard Field, the airport's former name, while Midway (MDW) and Rockford (RFD) are named after their respective locations.

Some airport codes are derived from the airport's former or unofficial name. For example, Chicago's O'Hare International Airport is coded ORD for its original name, Orchard Field. Kahului Airport's code is OGG, named after the local aviation pioneer Jimmy Hogg. Orlando International Airport's MCO code comes from McCoy Air Force Base.

Airport codes can also be derived from the location of the airport within a city or metropolitan area. For instance, the codes for Bucharest (BUH) and Otopeni (OTP) refer to the town of Otopeni, where the airport is located, while the business airport within Bucharest is named Băneasa (BBU). Jakarta (JKT) – Soekarno–Hatta (CGK) is named after Cengkareng, the district in which the airport is located, while the city's other airport, Halim Perdanakusuma (HLP), is named after its location.

In some cases, airport codes are influenced by the presence of a weather station at the airport. When the Canadian government established airports, it used the existing two-letter Morse codes assigned to railway stations and added a "Y" to indicate the presence of a weather station or another letter if it did not have one. As a result, many Canadian airport codes start with the letter "Y", although not all "Y" codes are Canadian, and not all Canadian airports start with "Y".

Rules for avoiding code duplication

The International Air Transport Association (IATA) assigns airport codes, which are three-letter geocodes that identify airports and metropolitan areas. To avoid code duplication, the IATA follows a set of rules and guidelines.

Firstly, the IATA maintains a minimum distance separation between similar codes. Specifically, the rule states that "the first and second letters or second and third letters of an identifier may not be duplicated with less than 200 nautical miles separation." This rule ensures that nearby airports have distinct codes, reducing confusion. For example, the three airports in the Washington, D.C. area adhere to this rule: IAD for Washington–Dulles, DCA for Reagan National Airport, and BWI for Baltimore/Washington International.

Secondly, when an airport is assigned a code, it rarely changes, even if the airport's name changes. For instance, Nashville International Airport, which opened in 1987, still uses the code BNA, which was initially assigned to the city's original airport, Berry Field. Similarly, Chicago's O'Hare International Airport (ORD) retains its code, which stands for its former name, Orchard Field.

In some cases, airport codes are derived from the airport's unofficial name or a notable figure associated with it. For example, Kahului Airport's code is OGG, honouring local aviation pioneer Jimmy Hogg. Additionally, certain codes may indicate the presence of a weather station at the airport. For instance, many Canadian airport codes start with the letter "Y", which was originally added to railway station codes to indicate the existence of a weather station.

To summarise, the IATA employs a combination of rules, including geographical separation, historical consistency, and unique identifiers, to avoid code duplication for airports worldwide. These guidelines ensure efficient airport identification and operations while minimising potential confusion.

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