FAA Aviation Mechanic Airframe (AMA)Landing Gear SystemsEasy
A technician is troubleshooting a hydraulically actuated nose wheel steering system. Turning the cockpit tiller produces no nose wheel movement even though hydraulic pressure and quantity are normal. Which component most directly controls the direction and rate of fluid flow to the steering cylinders in response to tiller input?
- ASteering metering valve
- BTorque link assembly
- CShimmy damper
- DSequence valve
Show answer & explanationAnswer & explanation
Correct answer: A. Steering metering valve
The steering metering valve translates mechanical tiller input into a proportional hydraulic signal that directs fluid flow to the steering cylinders, controlling both direction and rate of nose wheel turn. A failure in this valve would prevent tiller input from producing steering movement even with normal system pressure.
Why the other options are wrong
- B. The torque link transmits rotational alignment loads, not fluid control.
- C. The shimmy damper dampens oscillation, it does not control steering direction.
- D. A sequence valve times the order of gear extension/retraction, unrelated to steering.
Nose Wheel Steering Metering Valve
A valve that converts tiller (or rudder pedal) input into hydraulic flow directed to steering actuators to turn the nose wheel.
- Mechanically linked to the cockpit tiller
- Meters flow direction and rate to steering cylinders
- Failure causes no nose wheel response despite normal pressure
- Distinct from shimmy dampers and sequence valves
Memory trick: Tiller talks, metering valve translates, cylinder turns.