FAA Aviation Mechanic Airframe (AMA)Hydraulic and Pneumatic SystemsMedium
A technician needs to service a landing gear emergency pneumatic system's storage bottle with nitrogen from a service cart. Which fitting, incorporating an internal check valve, allows the bottle to be charged while automatically sealing to prevent pressure loss when the servicing cart hose is disconnected?
- ASequence valve
- BRestrictor check valve
- CCharging (filler) valve
- DSystem relief valve
Show answer & explanationAnswer & explanation
Correct answer: C. Charging (filler) valve
A charging (filler) valve is a spring-loaded check-valve fitting installed on pneumatic or accumulator systems specifically for ground servicing. It allows a service cart to pump nitrogen or air into the system, then automatically seals when the hose is removed, retaining the charged pressure without requiring a separate shutoff valve.
Why the other options are wrong
- A. A sequence valve times actuator operation order, unrelated to bottle servicing.
- B. A restrictor check valve meters flow in one direction within the system, not for external servicing.
- D. A relief valve protects against overpressure but is not designed for servicing connections.
Charging (Filler) Valve
A spring-loaded check-valve fitting used to service pneumatic bottles or accumulators with gas from a ground cart, automatically sealing when the servicing hose is disconnected.
- Contains an internal check valve for automatic sealing
- Commonly used for nitrogen or air servicing of accumulators/bottles
- Prevents pressure loss without needing a manual shutoff valve
Memory trick: Charging valve: like a bike tire valve that seals itself after pumping