Hydraulic and pneumatic power systems

Question 1

What kind of filter is micronic filter?

Answer 1

A filter with a special paper element

Question 2

What is a double action pump?

Answer 2

A pump that delivers fluid with the movement of the pump handle in both directions

Question 3

Why do most engine-driven hydraulic pumps have a shear section in their drive coupling?

Answer 3

The pump should seize, the shear section will break, disconnecting the pump from the engine and preventing further damage

Question 4

Does the main hydraulic fluid pump take its fluid from the bottom of the reservoir, or from the standpipe?

Answer 4

The main hydraulic normally takes its fluids from the standpipe, while the emergency pump takes its fluid from the bottom of the reservoir.

Question 5

Why are some hydraulic reservoirs pressurized?

Answer 5

Pressurization ensures that fluid will be supplied to the inlet of the pumps at high altitude where there is not enough atmospheric pressure to do this

Question 6

What are the two way aircraft hydraulic reservoirs may be pressurized?

Answer 6

By an aspirator in the fluid return line or by bleed air from the engine compressor

Question 7

What is used to flush a hydraulic system that uses Skydrol hydraulic fluid?

Answer 7

Solvent recommended by the aircraft manufacturer

Question 8

What is used to flush mineral base hydraulic fluid?

Answer 8

Naphtha, Varsol, or Stoddard solvent

Question 9

What type of pump is gear pump considered?

Answer 9

A gear pump is constant displacement, high pressure pump

Question 10

What type of pump is a piston pump with a variable cam plate considered?

Answer 10

Fuel pumps may be divided into two distinct system categories: 1- constant displacement and 2- variable displacement. A piston pump with a variable cam changes the effective (not actual) length of each piston stroke. this makes this type of pump a variable displacement with constant pressure

Question 11

Is a Chevron seal a one way or two way seal?

Answer 11

A one way seal

Question 12

To which side the Chevron seal should the pressure be applied?

Answer 12

To the open side

Question 13

Is an O-ring seal a one way or two way seal?

Answer 13

A two way seal

Question 14

How can you be sure of getting a O ring make of the correct material for a specific hydraulic component?

Answer 14

The O-ring must have the correct part number and it must have been obtained from a reputable source

Question 15

On which side of an O-ring should the backup ring be placed?

Answer 15

On the side away from the source of pressure

Question 16

What should be done to the sharp edges of threads and actuator pistons when installing O-ring?

Answer 16

The sharp edges should be covered with paper