FAA Aviation Mechanic Airframe (AMA)Hydraulic and Pneumatic SystemsEasy
A technician is inspecting a hydraulic reservoir equipped with a standpipe extending up from the bottom. The normal system pump draws fluid through the standpipe, while the emergency system pump draws fluid directly from the very bottom of the reservoir, below the standpipe opening. What is the purpose of this arrangement?
- ATo ensure the normal system consumes all reservoir fluid before the emergency system activates
- BTo reserve a supply of fluid exclusively for the emergency system if the normal system develops a major leak
- CTo filter debris before it enters the reservoir return line
- DTo vent trapped air from the reservoir during ground servicing
Show answer & explanationAnswer & explanation
Correct answer: B. To reserve a supply of fluid exclusively for the emergency system if the normal system develops a major leak
Because the normal system draws through the elevated standpipe, a leak in the normal system can only drain fluid down to the standpipe's opening level. The fluid remaining below that level is inaccessible to the normal system but is available to the emergency pump connected at the true bottom of the reservoir.
Why the other options are wrong
- A. The standpipe doesn't sequence system usage, it protects a fluid reserve.
- C. Filtering is done by system filters, not the standpipe geometry.
- D. Air venting is handled by a reservoir air/vent valve, not the standpipe.
Reservoir Standpipe
A tube extending upward from the bottom of a hydraulic reservoir through which the normal system draws fluid, leaving a reserve below its opening for the emergency system.
- Normal system draws from top of standpipe
- Emergency system draws from reservoir bottom
- Protects against total fluid loss from a normal-system leak
Memory trick: Standpipe = savings account fluid the normal system can't touch.