AMT Hydraulic and Pneumatic Systems Questions and Answers

Question 1

An aircraft hydraulic system's reservoir is pressurized. What is the primary reason for this pressurization, especially for aircraft operating at high altitudes?

Accepted Answer

To provide a positive fluid flow and prevent pump cavitation.

Answer

To increase the thermal capacity of the hydraulic fluid.

Answer

To automatically purge any trapped air from the system.

Answer

To serve as a secondary source of pressure for the brakes.

Question 2

A technician is servicing an aircraft that uses Skydrol, a phosphate-ester based hydraulic fluid. Which of the following is a critical safety and maintenance consideration when handling this type of fluid?

Accepted Answer

Skydrol is an excellent solvent and can damage many paints, plastics, and adhesives.

Answer

Skydrol is compatible with natural rubber seals and hoses.

Answer

It is non-toxic and requires no special personal protective equipment.

Answer

It is highly flammable and must be kept away from ignition sources.

Question 3

What is the primary function of a hydraulic accumulator in an aircraft system?

Accepted Answer

To store hydraulic fluid under pressure to supplement the pump or be used in emergencies.

Answer

To filter contaminants from the hydraulic fluid before it enters the pump.

Answer

To cool the hydraulic fluid by radiating heat into the surrounding structure.

Answer

To mix air with the hydraulic fluid to enhance its compressibility.

Question 4

In a high-pressure pneumatic system, what is the purpose of a relief valve?

Accepted Answer

To protect the system from damage by venting excess pressure above a preset limit.

Answer

To regulate the downstream pressure to a constant, usable level for specific components.

Answer

To add moisture to the compressed air to prevent seals from drying out.

Answer

To direct the flow of air to different actuators within the system.

Question 5

A hydraulic actuator with a piston area of 5 square inches is required to produce a force of 15,000 pounds. Based on Pascal's Law, what is the minimum system pressure required to achieve this force, neglecting any friction or back pressure?

Accepted Answer

3,000 PSI

Answer

75,000 PSI

Answer

5,000 PSI

Answer

1,500 PSI

Question 6

Which of the following is a primary method for removing moisture that has condensed in an aircraft pneumatic system?

Accepted Answer

Using drain valves located at low points in the system.

Answer

Injecting a desiccant fluid into the pneumatic lines during operation.

Answer

Heating the entire system with bleed air to evaporate the water.

Answer

Increasing system pressure to force the water back into a gaseous state.