The primary purpose of Doc 7910 is to standardize aerodrome identification across international boundaries. While IATA three-letter codes are used for passenger ticketing and baggage handling, ICAO four-letter codes (e.g., KJFK for New York-JFK, EGLL for London Heathrow) are used in operational and technical contexts, such as:
If an airport is permanently closed, its code is removed from the current edition of DOC 7910. However, rescinded codes are listed in an archive section for historical reference (to prevent re-use for a specific number of years). doc 7910 pdf
: Globally unique codes assigned to specific geographical locations. The primary purpose of Doc 7910 is to