FAA Aviation Mechanic Airframe (AMA)Landing Gear SystemsMedium
During overhaul of a main landing gear shock strut, a technician inspects the pin that allows the strut assembly to pivot in the wing or fuselage attachment fitting during retraction and extension. What is this pivot pin called?
- ATorque link pin
- BTrunnion pin
- CDownlock pin
- DAxle pin
Show answer & explanationAnswer & explanation
Correct answer: B. Trunnion pin
The trunnion is the pivot point/pin that attaches the main landing gear strut to the structure, allowing it to rotate as the gear retracts and extends. It carries significant structural loads and is closely inspected for wear and corrosion.
Why the other options are wrong
- A. Torque link pins connect the upper and lower torque link arms, not the strut pivot.
- C. A downlock pin secures the gear in the extended position, unrelated to pivoting.
- D. The axle supports the wheel, not the strut's pivot to the airframe.
Trunnion (Pivot Pin)
The structural pin/journal that attaches the main landing gear strut to the aircraft structure, allowing rotation during retraction and extension.
- Carries heavy structural and landing loads
- Allows gear to rotate/pivot during retraction
- Closely inspected for cracks, wear, and corrosion
Memory trick: 'Trunnion turns the whole gear like a hinge'