Definition
A system installed in retractable-gear aircraft that automatically alerts the pilot, typically through an aural horn and/or warning light, when the landing gear is not extended and locked under flight conditions associated with landing — most commonly when the throttle is reduced below a set power setting, when flaps are extended beyond a certain position, or both.
Plain English
A built-in alarm that tells the pilot the wheels are still up when the airplane is set up to land. It usually sounds a horn or lights up a warning if you pull the power back or put the flaps down with the gear retracted.
Context Anchor
Seen in retractable-gear aircraft during approach, landing checks, and maintenance checks of the gear system.
Why Pilots Care
It prevents gear-up landings that can damage the aircraft and injure occupants.
Intuition Check
Do not confuse the landing gear warning system with a gear position indicator. The warning system alerts the pilot to a possible unsafe gear condition; it does not by itself lower the gear or prove the gear is locked.
Example Sentence 1
On final approach, the pilot reduced power and immediately heard the landing gear warning system horn, reminding him he had not yet lowered the gear.
Example Sentence 2
After takeoff the pilot verified the landing gear warning system stayed silent once the gear was retracted and locked.