This blog provides an overview of the tower light signals used in the event of a radio communication failure.
Visual signals have been used for communication by pilots and air traffic controllers since the early days of aviation when radio was not developed not that much and the equipment was trustworthy .
These included flags and light signals. Unlike Controller Pilot Data Link Communications (CPDLC) which can be used in a wide variety of situations, the visual signals are limited to a few safety-critical messages.
These days visual signs are as yet utilized at aerodrome control towers as a backup if there should be an occurrence of radio failure . The ATC utilizes a light or a flare gun to send the messages.
Very large light gun is a yet at the same time handheld like projector which is focused on the airplane. The ATC utilizes a trigger to communicate with either a progression of heartbeats or a persistent stream of light and may pick the shade of the bar (red, green or white).
|Signal||To Aircraft in Flight||To Aircraft on the Ground|
|Steady green||Cleared to land||Cleared to takeoff|
|Steady red||Give way to other aircraft and continue circling||Stop|
Series of green flashes
|Return for landing*||Cleared to taxi|
|Series of red flashes||Aerodrome unsafe, do not land|
Taxi clear of landing area in use
|Series of white flashes||Land at this aerodrome and proceed to apron*|
Return to starting point on the aerodrome
Affirmation from the AIRCRAFT:
During sunlight hours, ATC signals are recognized by PILOTS :
- shaking the airplane’s wings if the airplane is in flight.
- moving the airplane’s ailerons or rudder if the airplane is on the ground.