Definition
A standardized set of colored light beams (steady or flashing green, red, or white) directed from the control tower at an aircraft to convey clearances and instructions when normal two-way radio communication is not available. Each color and pattern carries a specific meaning that differs depending on whether the aircraft is in flight or on the ground.
Plain English
If your radio stops working, the tower can shine a colored light at your aircraft to tell you what to do. Different colors and flashing patterns mean different things, like 'cleared to land' or 'return to airport.'
Context Anchor
Used in lost communication procedures, especially near or at a towered airport when the pilot cannot communicate by radio.
Why Pilots Care
They provide the only immediate instructions from the tower, allowing the flight to continue safely instead of creating a hazard or forcing an unnecessary diversion.
Intuition Check
Light signals are not general airport lighting, such as runway lights or beacon lights. In this context, they are deliberate instructions from the control tower to a specific aircraft or vehicle.
Example Sentence 1
After the radio failed on downwind, the pilot watched for light signals from the tower and received a steady green, clearing the aircraft to land.
Example Sentence 2
A flashing red light signal told the aircraft to taxi clear of the active runway immediately.