Utility Hydraulic System Overview

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What allows 115VAC to the cooler fan?

The 140K2 relay receives 28VDC from the thermal switch. (correct)

The UTIL HYD COOLING BLOWER circuit breaker is activated.

The UTIL BLO CONTR circuit breaker is activated.

The temperature bulb transmits an electrical signal to the utility hydraulic system fluid temperature indicator.

If the No.1 AC system fails, what will happen to the utility oil cooler fan?

It will continue to operate using the No.1 DC system.

It will operate at a reduced speed.

It will not function. (correct)

It will continue to operate using the 28VDC thermal switch.

What is the purpose of the temperature bulb in the reservoir/cooler system?

To transmit an electrical signal to the utility hydraulic system fluid temperature indicator. (correct)

To control the cooler fan operation.

To provide a visual indication of the fluid temperature.

To cool the hydraulic fluid.

Where is the thermal switch located in the reservoir/cooler system?

On the supply port of the reservoir/cooler. Signup and view all the answers

What is the temperature at which the cooler fan will be activated?

63° C (146°F) Signup and view all the answers

How many sources of electrical power are required for the utility cooler fan to operate?

Two Signup and view all the answers

What is the relationship between the temperature bulb and the thermal switch in the reservoir/cooler system?

They are both activated by the fluid temperature. Signup and view all the answers

What is the role of the cooler section in the utility hydraulic system?

To cool hydraulic fluid. Signup and view all the answers

What is the purpose of the brake transfer valve?

To prevent over-pressurization of the brake cylinder seals Signup and view all the answers

How many brake master cylinders are there in the system described?

Three Signup and view all the answers

What is the pressure used to operate the brake master cylinders?

1390 PSI Signup and view all the answers

Which part of the brake master cylinder allows pressurized fluid to return to the utility system once the brakes are released?

Return port Signup and view all the answers

What is the role of the springs located in the bottom of the master cylinder?

To open an internal check valve during brake application Signup and view all the answers

Where are the transfer valves located?

Behind the canted console, left of the parking brake valve Signup and view all the answers

What prevents system pressure from entering the return system during brake application?

The internal check valve Signup and view all the answers

Which of the following is NOT true about the brake master cylinder system?

The pilot and co-pilot brakes can be applied at the same time. Signup and view all the answers

What does the utility hydraulics system provide power for during normal operations and emergency situations?

Engine starting, brakes, and cargo handling Signup and view all the answers

Which of the following subsystems is NOT powered by the utility hydraulic system?

Electrical system Signup and view all the answers

What should students recycle? (Select all that apply)

Cardboard Signup and view all the answers

What is the risk assessment level of the training?

Low Signup and view all the answers

Where is the evaluation conducted?

Written examination Signup and view all the answers

Which of these is NOT a part of the utility hydraulic system?

Flight control system Signup and view all the answers

Which of these are NOT mentioned as relevant safety regulations?

Wearing safety goggles and gloves Signup and view all the answers

What is the main purpose of the Pressure Control Module (PCM)?

Regulating the pressure of the hydraulic system Signup and view all the answers

What is the primary function of the swivel lock pilot solenoid valve?

To allow fluid flow to centering cams of the aft landing gear assemblies Signup and view all the answers

What pressure must the accumulator be depressurized to for an accurate reading of pre-charge?

1400 PSI Signup and view all the answers

How is the swivel lock engaged when hydraulic pressure is applied?

By displacing the piston downward to a detent Signup and view all the answers

What condition must be met for the steering lever to be connected to the actuator rod end?

The steering alignment must be rigged correctly Signup and view all the answers

What triggers the out of phase switch in the cam and wheel centering assembly?

When the wheel turns past the maximum angle limits Signup and view all the answers

What action is taken to depressurize the power steering and swivel lock module?

Cycle the swivel lock switch from LOCK to UNLOCK repeatedly Signup and view all the answers

What role does the feedback potentiometer play in the power steering actuator assembly?

It sends signals to the power steering control box Signup and view all the answers

What happens when the switch is set to UNLOCK in the swivel lock actuator?

Hydraulic pressure is removed from the upper port Signup and view all the answers

What is the pressure differential that causes the DPI button to extend on the filter bowl assembly?

75 PSID + 10 Signup and view all the answers

When does the bypass feature of the filter bowl assembly activate?

When the differential pressure exceeds 130 PSID. Signup and view all the answers

What triggers the PUMP FAULT light on the maintenance panel for the APU motor/pump?

Flow rate through case drains exceeding 1.0 GPM + 0.25 GPM. Signup and view all the answers

Which of these components is NOT directly related to the ramp operation?

Utility Boost Pump Signup and view all the answers

What is the purpose of the Ramp Transfer Cylinder?

To provide additional fluid flow for the ramp actuating cylinders during ramp operation. Signup and view all the answers

What happens when the ramp control valve is in the STOP position?

Fluid flow is locked between the actuating cylinders and the ramp control valve. Signup and view all the answers

Where is the Utility Boost Pump located?

Mounted to and driven by the aft transmission on the No.2 side of the accessory drive pad. Signup and view all the answers

Which port is open when the ramp control valve is operated to STOP?

Port C3 Signup and view all the answers

What is the supply pressure for the Utility Boost Pump?

60 PSI Signup and view all the answers

What is the minimum pressure required to unlock the ramp locking mechanism?

400 PSI Signup and view all the answers

What is the maximum flow rate of the Utility Boost Pump?

16 GPM Signup and view all the answers

In the DN position of the ramp control valve, what is the role of port C3?

It allows pressurized fluid to flow to the ramp unlock port. Signup and view all the answers

Which statement is true about the ramp actuating cylinders?

They both have a stroke of 16.2 inches. Signup and view all the answers

What happens to the fluid during the UP position of the ramp control valve?

Fluid flows into the actuating cylinders to lift the ramp. Signup and view all the answers

How many ports do the ramp actuating cylinders have?

Three ports each Signup and view all the answers

What does the RAMP PWR switch control in the ramp system?

The activation of the solenoid valves. Signup and view all the answers