from Stapleton International Airport to Denver International Airport in 1996, and AUS/KAUS, which migrated from Austin Mueller Municipal Airport to Austin-Bergstrom International Airport in 1999. Both of these cases occurred because the original locations were closed. Occasionally a code will be discontinued entirely, with no successor. Sometimes this is a small airport that has closed, such as Stone Mountain Airport, whose identifier 00A is now used for an R/C heliport in Bensalem, Pennsylvania. In another case, the identifiers for Idlewild Airport in New York were changed to JFK and KJFK when it was renamed after John F. Kennedy, and its original IDL and KIDL were later reused for Indianola Municipal Airport in Indianola, Mississippi. Transplanted identifiers tend to be poorly documented, and can cause problems in data systems and software which process historical records and in research and legal work. A similar problem also exists for broadcast callsigns. See also UN/LOCODE: locations used in trade and transport with functions such as seaports, rail and road terminals, airports, Postal Exchange Office and border crossing points References External links NCDC Station Locator - Historical search engine for U.S. weather station locations Weather Station Identifiers - References for worldwide identifiers DGAC Code Коды городов - City codes (including Russian codes World Airport and Runway Map (official site) Aircraft operations Encodings Navigational aids