FAA Aviation Mechanic Airframe (AMA)Hydraulic and Pneumatic SystemsHard
A technician troubleshooting a hydraulic system finds that a component allows free flow in one direction but restricts flow to a much smaller rate in the opposite direction, used to slow landing gear retraction speed. What component is this?
- AAn orifice (restrictor) check valve
- BA pressure reducing valve
- CA simple check valve
- DA sequence valve
Show answer & explanationAnswer & explanation
Correct answer: A. An orifice (restrictor) check valve
An orifice check valve, also called a restrictor check valve, allows unrestricted flow in one direction and restricted flow through a small orifice in the opposite direction, commonly used to control actuator speed such as landing gear retraction. A simple check valve blocks flow entirely in one direction rather than restricting it.
Why the other options are wrong
- B. Pressure reducing valves lower pressure to a subsystem, not control flow direction/speed.
- C. A simple check valve fully blocks reverse flow rather than restricting it.
- D. Sequence valves control the order of actuator operation, not flow rate.
Orifice (Restrictor) Check Valve
A valve that allows full flow in one direction and restricted, metered flow through an orifice in the reverse direction.
- Used to control actuator speed (e.g., gear retraction)
- Differs from simple check valve which fully blocks reverse flow
- Common in landing gear and flap systems
Memory trick: One way is a highway, the other way is a tiny tunnel.