Airframe Systems and Components (Hydraulics and Pneumatics)

Question 1

What are the three principal categories of hydraulic fluids?

Answer 1

Mineral, Polyalphaolefin, phosphate ester

Question 2

what color is mineral based hydraulic fluid?

Answer 2

Red (5606)

Question 3

how do you determine which type of hydraulic fluid do use any specific system?

Answer 3

In the aircraft maintenance manual, or on the instruction plate attached to the reservoir.

Question 4

What will happen to the seals in a vegetable base hydraulic system if it is service with a mineral base or phosphate master base fluids?

Answer 4

The seals will swell, breakdown, and block the system.

Question 5

When installing a Chevron seal what must be considered?

Answer 5

And chevron seal must be installed with pressure going toward the open side of the seal.

Question 6

When hydraulic lines have been disconnected, what precaution should be taken to prevent contamination of the system?

Answer 6

All hydraulic lines and fittings should be capped or plugged immediately after disconnecting.

Question 7

What happens to the hydraulic fluid flow if the filter element becomes clogged with foreign matter?

Answer 7

There is a bypass valve which routes the hydraulic fluid directly from the inlet port to the outlet port.

Question 8

What is a Micronic filter?

Answer 8

Hey filter with a paper element.

Question 9

Name the filters used in aircraft pneumatic systems?

Answer 9

Paper pleated and screen type.

Question 10

Why are some hydraulic reservoirs pressurized?

Answer 10

To ensure a positive flow of fluid to the engine driven pump at high altitudes.

Question 11

What methods are used to pressurize hydraulic reservoirs?

Answer 11

Variable displacement hydraulic pump, engine bleed air, or hydraulic system pressure acting on a small piston in the reservoir. another method is an aspirator or Venturi.

Question 12

What are the two types of hydraulic accumulators?

Answer 12

Spherical , and cylindrical

Question 13

Name the three types of hydraulic accumulators.

Answer 13

Diaphragm type, bladder type, and piston type.

Question 14

What is the purpose of a pressure relief valve in a hydraulic system?

Answer 14

To limit the amount of pressure in the system. (safety valve)

Question 15

What is the purpose of an unloading valve in a closed hydraulic system?

Answer 15

It acts as a pressure regulator. Designed to provide a low pressure path for the return fluid to flow from the pump back to the reservoir when the system has no flow requirements.

Question 16

What is the function of a wing flap overload valve?

Answer 16

to prevent possible structural damage to the flap or the flap system from flaps being lowered at excessive speeds.

Question 17

What is the purpose of the shearable section in a hydraulic pump?

Answer 17

the shear section will disconnect the pump from the engine if the pump were to seize. This allows engine to continue to operate.

Question 18

What are two different types of hydraulic pumps?

Answer 18

Hand pumps and power pumps (positive and nonpositive displacement)

Question 19

what pump is most suitable for low pressure pneumatic systems?

Answer 19

Vane type pump

Question 20

what protects a direct-pressure type hydraulic pressure gauge from pressure surges?

Answer 20

A dampening device in the form of a very small restrictor is installed in the line leading to the gauge, or at the inlet of the gauge itself.

Question 21

what are pneumatic systems used for in aircraft?

Answer 21

Brakes, open and close doors, starting, pump driving, and operating emergency devices.

Question 22

What happens to the air after a pneumatic starter is operated?

Answer 22

The air is dumped overboard.

Question 23

Why should a pneumatic system be purged periodically?

Answer 23

To remove contamination, moisture, oil from the components and lines.

Question 24

What is the purpose of the relief valve in a pneumatic system?

Answer 24

Protect system against thermal expansion by venting excess pressure to the atmosphere.

Question 25

What is the purpose of an accumulator?

Answer 25

To prevent hydraulic system shock when under high load demand conditions.

Question 26

what is an example of a phosphate ester base fluid?

Answer 26

Skydrol