AME Hydraulic and Pneumatic Systems 2

Question 1

What color is MIL-PRF-5606 mineral-based hydraulic fluid?

Accepted Answer

Red

Answer

MIL-PRF-5606 petroleum-based fluid is dyed red for identification.

Question 2

Which seal material is compatible with phosphate ester (Skydrol) hydraulic fluid?

Accepted Answer

Butyl rubber or ethylene propylene

Answer

Phosphate ester fluids attack nitrile and neoprene, so butyl or EPR seals are required.

Question 3

What is the typical color of Skydrol phosphate ester hydraulic fluid?

Accepted Answer

Light purple

Answer

Skydrol fluids are dyed light purple to distinguish them from mineral-based fluids.

Question 4

Before checking the air preload on a hydraulic accumulator, what must be done?

Accepted Answer

Relieve all hydraulic system pressure

Answer

Preload can only be read accurately when fluid pressure is zero so the gauge shows nitrogen charge alone.

Question 5

A 1,000 psi hydraulic pressure acts on a piston with a 2-square-inch area. What force does the piston produce?

Accepted Answer

2,000 pounds

Answer

Force equals pressure times area, so 1,000 psi x 2 sq in = 2,000 lb.

AME - Aircraft Maintenance Engineer Practice Test