Airport ID’s

In the 48 contiguous states of the US, (almost universally) merely adding a K to the beginning of the IATA (International Air Transport Association, aka, airlines) or FAA identifier gives the ICAO (International Civil Aviation Organization) ID. So, STL (St. Louis’ Lambert Field to the airlines and FAA, becomes KSTL internationally). The US is lucky this way, versus other countries where there’s no obvious connection, e.g., “DEL” (IATA Delhi, India) vs its ICAO “VIDP” or Narita’s (NRT) and its ICAO of “RJAA”.

The first letter of the ICAO (International Civil Aviation Organization) gives the region of the world. The second refines that to the country or area of a country (India has four areas, A, E, I, O, [but no U!]) and the last two specify the airport. Many IATA and FAA ID’s in the US are pretty easy to figure out (MSP is Minneapolis-St. Paul, MEM is Memphis, TN), while others aren’t: Chicago O’Hare is ORD, from the old ORcharD Field, while Knoxville, TN is TYS for McGee-Tyson Field and Scottsboro, AL is 4A6 for, well, I’m not sure.

Other examples of ICAO are: Anchorage, AK = PANC (Pacific, Alaska, NC-Anchorage) and Hilo, HI = PHTO (Pacific, Hawaii, TO-Hilo). The last two letters may be chosen in order to make the ICAO ID clearer, such as Anchorage’s.

Some aviation weather sources (aviationweather.gov for one, aka AWC) require the 4-part ICAO ID to display the weather. MEX for Mexico City won’t work, but MMMX will. Scottsboro’s 4A6 won’t do, but K4A6 will get you the weather data you need for that flight down to the Tennessee River Valley.

Chapter 22 in the latest (12th edition) of The Student Pilot’s Flight Manual covers the very useful AWC in some detail.