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

500–1,000 psi

Answer

1,500–2,000 psi

Answer

8,000–10,000 psi

Question 2

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

Accepted Answer

Skydrol (phosphate ester)

Answer

MIL-PRF-5606 (red mineral oil)

Answer

MIL-PRF-83282 (synthetic hydrocarbon)

Answer

Water-glycol

Question 3

What is the function of a hydraulic accumulator?

Accepted Answer

Store pressurized fluid and dampen pressure surges

Answer

Filter contaminants from fluid

Answer

Cool hydraulic fluid

Answer

Measure system pressure

Question 4

Which seal material is NOT compatible with Skydrol hydraulic fluid?

Accepted Answer

Buna-N (nitrile) rubber

Answer

Butyl rubber

Answer

Ethylene propylene (EPDM)

Answer

Teflon (PTFE)

Question 5

What is the purpose of a hydraulic system relief valve?

Accepted Answer

Limit maximum system pressure to protect components

Answer

Reduce flow to actuators

Answer

Control actuator speed

Answer

Separate fluid from air

Question 6

How is hydraulic fluid contamination level typically classified in aircraft maintenance?

Accepted Answer

By NAS 1638 or ISO 4406 cleanliness codes

Answer

By color and viscosity only

Answer

By FAR Part 43 fluid specs

Answer

By MIL-SPEC gravity rating