AM AM Hydraulic & Pneumatic Systems

Question 1

What is the typical operating pressure range for a large transport aircraft hydraulic system?

Accepted Answer

3,000–5,000 psi

Answer

Large transport aircraft hydraulic systems typically operate between 3,000 and 5,000 psi, with many modern aircraft using 5,000 psi systems for reduced weight.

Question 2

What fluid is specified for most Boeing commercial aircraft hydraulic systems?

Accepted Answer

Skydrol (phosphate ester)

Answer

Boeing commercial aircraft use Skydrol, a fire-resistant phosphate ester hydraulic fluid, to reduce fire risk in the event of a hydraulic leak.

Question 3

What is the function of a hydraulic accumulator?

Accepted Answer

Store pressurized fluid and dampen pressure surges

Answer

A hydraulic accumulator stores pressurized fluid under a pre-charged gas pressure to supplement pump output during peak demands and dampen pressure spikes.

Question 4

Which seal material is NOT compatible with Skydrol hydraulic fluid?

Accepted Answer

Buna-N (nitrile) rubber

Answer

Nitrile (Buna-N) seals swell and deteriorate rapidly when exposed to Skydrol phosphate ester fluid and must not be used in these systems.

Question 5

What is the purpose of a hydraulic system relief valve?

Accepted Answer

Limit maximum system pressure to protect components

Answer

A relief valve opens to return fluid to the reservoir when system pressure exceeds the set maximum, protecting pumps, actuators, and lines from over-pressurization.

(AM) Aircraft Maintenance Certification Practice Test

(AM) Aircraft Maintenance Certification Practice Test

AM AM Hydraulic & Pneumatic Systems