FAA Flight Instructor Airplane (FIA)Aircraft Systems and InstrumentsHard
A technician inspecting a retractable-gear airplane explains the purpose of the landing gear squat switch (weight-on-wheels switch) to a new pilot. What is its primary function?
- AIt automatically extends the landing gear when airspeed drops below a preset value
- BIt prevents inadvertent gear retraction while the airplane's weight is on the wheels, such as during ground operations
- CIt controls the flow of hydraulic fluid to the brakes during landing rollout
- DIt signals the autopilot to disengage upon touchdown
Show answer & explanationAnswer & explanation
Correct answer: B. It prevents inadvertent gear retraction while the airplane's weight is on the wheels, such as during ground operations
The squat switch senses whether the airplane's weight is resting on the landing gear struts. When weight is on the wheels, the switch interrupts the gear retraction circuit, preventing the pilot from accidentally retracting the gear while taxiing, during the takeoff roll before liftoff, or after landing, even if the gear handle is moved to the up position.
Why the other options are wrong
- A. Automatic gear extension based on airspeed is a separate safety system in some aircraft, not the squat switch's primary function.
- C. Brake hydraulic flow is unrelated to the squat switch.
- D. Autopilot disengagement is unrelated to the squat switch's function.
Squat Switch (Weight-on-Wheels Switch)
A safety switch on the landing gear strut that prevents gear retraction while the aircraft's weight is on the wheels.
- Located on the main landing gear strut
- Interrupts the gear retraction electrical circuit on the ground
- Distinct from airspeed-based automatic extension systems
Memory trick: 'Squat down, lock the gear up switch—no retracting while standing'