A&P A&P Aircraft Hydraulic & Pneumatic Systems 2

Question 1

In an aircraft pneumatic system, what is the most common source of high-pressure air used for system operation?

Accepted Answer

Bleed air tapped from the engine compressor stages

Answer

Most turbine-powered aircraft pneumatic systems use bleed air extracted from the engine's compressor section as the primary pressure source for flight controls, pressurization, and other pneumatic actuators.

Question 2

What is the function of a pneumatic system's pressure regulator?

Accepted Answer

Reduce high-pressure bleed air to a lower, usable system pressure

Answer

The pressure regulator reduces the very high pressure of engine bleed air to a lower, controlled pressure suitable for operating pneumatic components without damage.

Question 3

Why is moisture a critical concern in pneumatic systems, especially at high altitudes?

Accepted Answer

Moisture can freeze in lines and valves at altitude, causing blockages and system failure

Answer

Water vapor in pneumatic lines can freeze at the low temperatures encountered at altitude, blocking orifices, valves, and lines and causing system malfunctions.

Question 4

A hydraulic actuator that holds position under load without continuous fluid flow is best described as a:

Accepted Answer

Locked (mechanically locked) actuator

Answer

Mechanically locked actuators (such as those used for landing gear) hold their position through a mechanical lock so they do not require continuous hydraulic pressure to remain extended or retracted.

Question 5

What is the purpose of a debooster valve in an aircraft hydraulic brake system?

Accepted Answer

Reduce high system pressure to a lower, controllable pressure at the brake actuators

Answer

A debooster valve reduces the high hydraulic system pressure to a lower pressure suitable for the brake actuators, protecting brake components from overpressure.

A&P - Certified Aircraft Mechanic Practice Test

A&P - Certified Aircraft Mechanic Practice Test

A&P A&P Aircraft Hydraulic & Pneumatic Systems 2