Gera Tools

Aviation Light Signal Reference

ATC light gun signals and their meaning in the air and on ground

Reference table of FAA/ICAO ATC light gun signals — steady and flashing green, red and white — and what each means for aircraft in flight, aircraft on the ground, and vehicles, for radio-failure communication.

Aviation light signal reference

If an aircraft loses radio contact, the control tower can still direct it using a steerable light gun that emits steady or flashing beams of green, red or white light. Each signal carries a defined meaning, but that meaning changes depending on whether the receiver is an aircraft in flight, an aircraft on the ground, or a vehicle on the movement area. This tool lets you pick the context and shows the meaning of every signal for that situation.

How it works

The control tower selects a colour and a pattern (steady or flashing). The same colour can mean opposite things by context: a steady green clears an airborne aircraft to land but clears a ground aircraft for takeoff, while a flashing red tells an airborne pilot the airport is unsafe but tells a ground aircraft to taxi clear of the active runway. Some signals are only used in certain contexts — flashing white is a ground/vehicle signal (“return to your starting point”) and is not used in flight. Alternating red and green always means “exercise extreme caution”.

Tips and notes

  • Pilots acknowledge a signal without radio by rocking the wings during the day, flashing the landing or navigation lights at night, or moving the ailerons and rudder while on the ground.
  • The signals are identical under FAA (AIM) and ICAO (Annex 2) frameworks, which is why pilots worldwide memorise the same chart.
  • This is a study reference. In an actual radio failure, follow your published lost-comms procedures and the current regulatory documents.