APU Flashcards

1
Q

What information should be entered on the −13 if the APU ON caution light fails to come on?

A

Record the BITE information from the ESU

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The APU switch should be place to OFF if the APU fails to start or automatically shuts down. When this happens where should the battery switch be positioned?

A

Leave the battery switch on.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What action should you take if the UTIL HYD SYS caution light has not gone out within 30 seconds after the APU ON caution light comes on?

A

Place the APU switch to OFF position.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What 2 components are driven by the APU?

A

APU motor/pump, and APU generator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Control and monitoring of the APU is accomplished through what components.

A

The ESU.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What restriction is placed on APU operation during flight?

A

Emergencies only.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How long do you delay in the RUN position before going to START?

A

5 seconds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does the APU ON caution light indicate?

A

APU is operating properly.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How long must the APU switch be held at the START position during the start procedure?

A

2 seconds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the maximum tail wind for starting the APU?

A

25 Knots.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

After the APU control caution light comes on, how long may the utility Hydraulic caution capsule remain on?

A

30 seconds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When the APU is shutdown, how long should you wait before attempting a restart?

A

1 minute.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many horsepower is the APU

A

Max rating 95 SHP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Fuel consumption of APU

A

89-115 pounds per hour out of left main tank

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where does electrical power come from to control apu operations

A

Normally, electrical power to control apu operation is from the 28-volt essential DC bus through the APU CONT NORM circuit breaker on No. 1 power distribution panel.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the APU start module do?

A

Provides signal pressure for the APU motor pump.

17
Q

What does the APU motor pump do?

A

Motor drives the APU during the start sequence.

Pump provides the pressure for the utility hydraulic system during ground operations.

18
Q

What does the APU electronic sequencing unit do?

A

Monitors the APU during start and shut down.

19
Q

What is the APU fault relay?

A

Closes the fuel solenoid valve during ESU shut down of the APU.

20
Q

What does the APU fuel boost pump do?

A

Boost fuel pressure during APU start.

21
Q

What does the APU fuel solenoid valve do?

A

Stops fuel flow to the APU.

22
Q

What is the APU generator rated at?

A

20 KVA

23
Q

What’s the main difference between the APU engine and the 47’s 714 engine?

A

The APU is not a free-air type turbine. The compressor rotor and power turbine rotor are directly mounted to a common shaft. This is different from the T55−GA−714 Engine where the compressor section and power turbine section are free to rotate independently of one another.

24
Q

What does the manual depressurization valve do?

A

It is used to depressurize the APU start accumulator and the reservoir pressurization accumulator (URPA) to facilitate maintenance on the utility system. The valve is located on the bottom center of the apu start module.

25
Q

What does the pressure indicator on the apu start module indicate?

A

Pressure indicator should indicate system pressure in the APU start accumulator.

26
Q

How many PSI from the APU motor pump to start the engine?

A

Provides 3350 PSI of hydraulic pressure to start the main engines

27
Q

What’s the flow rate of the pump (utility) side of APU motor pump?

A

flow rate of 16.5 GPM

28
Q

The APU pump is a two delivery type pump. What two types?

A
  1. During APU start the motor/pump is a constant delivery motor.
  2. During normal operations the motor/pump is a variable delivery pump.
29
Q

Power supply for Airframe mounted APU fuel boost pump and APU Fuel solenoid valve?

A

Operates on 24/28 Volts Direct Current (VDC) off the hot battery bus, or the essential bus depending on the position of the battery switch.

30
Q

The APU main fuel metering valve has automatic altitude compensation up to?

A

15,000 ft

31
Q

What does the APU switch do?

A

The APU switch, a three position switch connects DC power to the APU system

32
Q

What does the APU fault relay do?

A

De-energizes the airframe mounted APU fuel boost pump and the APU fuel solenoid valve located in the aft left inter-tank area during an ESU shutdown of the APU. When ESU detects a fault, fault relay is energized and interrupts voltage to pump and valve.

33
Q

Where is the oil sight gauge for the apu?

A

Has an oil level sight gage that faces the No.1 side of the aircraft.

  1. When the oil level is at the bottom of the sight glass, approximately one pint of oil needs to be added.
  2. A hollow aluminum ball is caged in the sight glass.