Hydraulic and Pneumatic Systems Flashcards
6 cards from real A&P practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Hydraulic and Pneumatic Systems flashcards as text
What is the primary purpose of a hydraulic system relief valve on an aircraft?
Answer: To limit maximum system pressure and prevent overpressure damage
A hydraulic relief valve opens at a preset pressure to bypass fluid back to the reservoir, protecting system components from overpressure.
Which type of hydraulic fluid is used in most modern transport-category aircraft and is compatible with natural rubber seals?
Answer: Skydrol (phosphate ester)
Skydrol and similar phosphate ester fluids are used in most transport-category aircraft and require synthetic seals, not natural rubber.
What color is MIL-PRF-5606 mineral-based hydraulic fluid?
Answer: Red
MIL-PRF-5606 is red-dyed mineral oil hydraulic fluid, commonly used in general aviation aircraft.
In an aircraft hydraulic system, what is the function of the accumulator?
Answer: Store pressurized fluid to supplement the pump during peak demands
An accumulator stores a reserve of pressurized hydraulic fluid to supplement pump output during high-demand operations and damp pressure surges.
What is the purpose of a hydraulic power pack (self-contained unit) on light aircraft?
Answer: It replaces the engine-driven pump with an electric motor-driven pump, reservoir, and valve assembly
A hydraulic power pack integrates an electric pump, reservoir, selector valve, and actuator into one self-contained unit, commonly used for retractable landing gear on light aircraft.
When servicing an aircraft pneumatic system's air bottle, what must a technician verify before removing the filler valve?
Answer: That the bottle pressure has been bled to zero
The high-pressure air bottle must be fully depressurized to zero before removing any fittings or the filler valve to prevent a dangerous pressure release.