Hydraulic and Pneumatic Power Flashcards
7 cards from real Airframe Mechanic Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Hydraulic and Pneumatic Power flashcards as text
What happens to hydraulic fluid viscosity as temperature increases?
Answer: Viscosity decreases
Hydraulic fluid becomes thinner (less viscous) as temperature rises, which can affect sealing effectiveness and pump efficiency.
A hydraulic power pack is BEST described as:
Answer: A self-contained unit with pump, reservoir, and controls for a specific subsystem
A hydraulic power pack is a self-contained unit integrating a pump, reservoir, filter, and associated controls to power a specific aircraft subsystem.
When bleeding a hydraulic system, the purpose is to:
Answer: Expel trapped air to ensure solid, responsive actuator operation
Bleeding removes air pockets that cause spongy or sluggish actuator response because air is compressible unlike hydraulic fluid.
Skydrol hydraulic fluid is classified as:
Answer: A phosphate ester-based fire-resistant fluid
Skydrol is a phosphate ester-based, fire-resistant hydraulic fluid widely used in commercial transport aircraft.
What is the function of a hydraulic fuse?
Answer: To automatically shut off flow if a downstream line ruptures and flow exceeds a preset rate
A hydraulic fuse senses excessive flow caused by a downstream rupture and closes to isolate the failed section, preserving fluid for the rest of the system.
A pneumatic high-pressure storage bottle must be hydrostatically tested every:
Answer: 5 years
High-pressure pneumatic cylinders used in aircraft systems are required to undergo hydrostatic testing every 5 years per DOT/FAA regulations.
In a hydraulic system, cavitation in a pump is caused by:
Answer: Insufficient fluid supply to the pump inlet, causing vapor bubbles to form
Cavitation occurs when the pump inlet is starved of fluid, creating low-pressure voids that collapse violently and damage pump components.