An aeronautical identification beacon is a lighted beacon located at an aerodrome to help the pilots identify it at night. The colour of the beacon is:

• flashing-green at a land civil aerodrome
• flashing-yellow at a water civil aerodrome
• flashing-red at a military aerodrome

An aeronautical identification beacon transmits letters using flashes of light that follow the rhythm of Morse code. Each dot (·) and dash (–) is represented by a flash of light of different duration. A short flash idicates a dot and a long flash indicates a dash. Military aerodrome beacons transmit two letters to help you identify the aerodrome. Civil aerodrome beacons usually transmit three letters instead.

ICAO Annex 14
5.3.3 Aeronautical beacons

5.3.3.1 Where operationally necessary an aerodrome beacon or an identification beacon shall be provided at each aerodrome intended for use at night.

5.3.3.12 An identification beacon shall show flashing-green at a land aerodrome and flashing-yellow at a water aerodrome.

5.3.3.13 The identification characters shall be transmitted in the International Morse Code.

Aerodrome beacon. Aeronautical beacon used to indicate the location of an aerodrome from the air.

Identification beacon. An aeronautical beacon emitting a coded signal by means of which a particular point of reference can be identified.