Aviation light signals

An air traffic controller using a light gun that can be used to control aircraft with radio failure.

In the case of a radio failure or aircraft not equipped with a radio, or in the case of a deaf pilot, air traffic control may use a signal lamp to direct the aircraft. The signal lamp has a focused bright beam and is capable of emitting three different colours: red, white and green. These colors may be flashed or steady, and have different meanings to aircraft in flight or on the ground. Planes can acknowledge the instruction by rocking their wings, moving the ailerons if on the ground, or by flashing their landing or navigation lights during hours of darkness.

Signal	Aircraft in flight	Aircraft on the ground	Ground vehicles or personnel
Flashing white	ICAO - Land at this airport and proceed to apron (this is not a clearance to either land or taxi. Clearances to land and taxi will follow.) FAA - Not applicable	Return to starting point	Return to starting point
Steady green	Cleared to land	Cleared for takeoff	Cleared to cross/proceed
Flashing green	Cleared to approach airport, or return to land	Cleared to taxi	N/A
Steady red	Continue circling, give way to other aircraft	Stop	Stop
Flashing red	Airport unsafe, do not land	Immediately taxi clear of runway in use	Clear the taxiway/runway
Alternating red and green	Exercise extreme caution	Exercise extreme caution	Exercise extreme caution
Blinking runway aviation lights	Vehicles, planes, and pedestrians immediately clear landing area in use

References

• FAAO 7110.65 Air Traffic Control Chapter 3, Section 2: Visual Signals
• ICAO Annex II, Rules of the Air