A&P - Aircraft and Powerplant Hydraulic and Pneumatic Systems Flashcards
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Read the first 6 A&P - Aircraft and Powerplant Hydraulic and Pneumatic Systems flashcards as text
What is the primary purpose of a hydraulic system's thermal relief valve?
Answer: Relieve pressure caused by thermal expansion of trapped fluid
A thermal relief valve opens to relieve excess pressure caused by thermal expansion of hydraulic fluid trapped in a closed loop.
Which seal material is compatible with Skydrol hydraulic fluid?
Answer: Butyl rubber or ethylene propylene (EPDM)
Butyl rubber and EPDM seals are compatible with Skydrol; nitrile and neoprene seals are degraded by phosphate ester fluids.
How is a hydraulic actuator classified when it can produce force in both directions using hydraulic pressure?
Answer: Double-acting actuator
A double-acting actuator uses hydraulic pressure on both sides of the piston to produce powered movement in two directions.
What is indicated when hydraulic fluid appears milky or foamy?
Answer: Water contamination or air entrapment in the fluid
Milky or foamy hydraulic fluid indicates water contamination or air entrapment, both of which degrade system performance.
What is the function of a hydraulic fuse in an aircraft system?
Answer: Automatically shut off fluid flow if flow rate exceeds a preset limit due to a line break
A hydraulic fuse shuts off flow automatically when it detects excessive flow, protecting against system loss from a ruptured line.
In aircraft pneumatic systems, what component limits output pressure to a preset value regardless of source pressure?
Answer: Pressure regulator
A pressure regulator reduces and maintains downstream pressure at a constant preset level regardless of upstream pressure variations.