Definition
Electrical switches in a retractable landing gear system that automatically stop the gear motor or hydraulic pump when the gear reaches the fully extended (down-and-locked) or fully retracted (up-and-locked) position. They also signal gear position to cockpit indicators and warning systems.
Plain English
Small switches that sense when the landing gear has reached the end of its travel, either fully down or fully up, and shut off the system that was moving it. They also tell the cockpit lights and warnings what position the gear is in.
Context Anchor
Encountered in retractable landing gear discussions, especially when learning how gear motors, gear doors, and cockpit gear position lights are controlled.
Derivation
Called 'limit' switches because they detect the limit of mechanical travel — the point where the gear can move no further in that direction. Once that limit is reached, the switch acts.
Why Pilots Care
They prevent the motor from over-running and damaging the mechanism while confirming to the pilot that the gear has reached a safe, locked position.
Analogy
A refrigerator light switch is a simple comparison: when the door reaches the closed position, the switch changes state and the light turns off. A landing gear limit switch works on the same basic idea, but it is used to confirm gear or door position.
Intuition Check
Limit switches are not usually switches the pilot moves by hand. They are automatic switches that respond when a gear part reaches the end of its allowed travel.
Example Sentence 1
When the gear reached the down-and-locked position, the limit switch stopped the hydraulic pump and illuminated the green gear-down light.
Example Sentence 2
During the after-landing checklist the pilot confirmed that both limit switches had activated the green down lights.