Hydraulic & Pneumatic Systems Flashcards
7 cards from real ACS 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 & Pneumatic Systems flashcards as text
According to Pascal's Law, if 100 psi of pressure is applied to a closed hydraulic system, the pressure throughout the system is:
Answer: 100 psi everywhere in the system simultaneously
Pascal's Law states that pressure applied to a confined fluid is transmitted equally and undiminished in all directions throughout the fluid.
What is the advantage of a brake-by-wire (electro-hydraulic) braking system compared to a conventional hydraulic brake system?
Answer: Provides faster and more precise brake pressure modulation for anti-skid performance
Electro-hydraulic brake systems use electronic control to modulate hydraulic pressure with greater speed and precision than mechanical inputs alone, improving anti-skid performance.
When installing a hydraulic fitting using the B-nut (union nut) method on a flared tube, what is the correct sequence?
Answer: Slide the B-nut onto the tube before flaring, then flare the tube and tighten
The B-nut must be slid onto the tube before flaring because the nut cannot pass over a completed flare, making pre-positioning mandatory.
What is the function of a hydraulic system priority valve?
Answer: Ensure flight-critical systems receive hydraulic pressure before non-critical systems during low-pressure conditions
A priority valve ensures that flight-critical hydraulic consumers (such as flight controls) are served first, with non-essential systems receiving flow only when adequate pressure exists.
What type of fitting is typically used on high-pressure aircraft hydraulic lines (3,000 psi and above) where vibration is a concern?
Answer: Flareless MS fitting with bite-type ferrule
MS flareless (bite-type) fittings are preferred for high-pressure, high-vibration applications because the ferrule bites into the tube and provides excellent resistance to loosening.
What does a hydraulic snubber do in a pressure gauge line?
Answer: Dampens pressure surges to protect the gauge and provide a steady reading
A snubber is a small orifice or restriction that dampens rapid pressure pulsations, protecting the gauge bourdon tube from fatigue damage and providing a readable steady indication.
What is the correct procedure when a hydraulic system component is found to have a minor external seepage (not a drip) at a fitting?
Answer: Clean the area and monitor for progression; replace if seepage becomes a drip or increases
Minor seepage that forms no drips is typically acceptable per maintenance manuals — it should be cleaned, identified, monitored, and addressed if it worsens to an active leak.