APU

Question 1

What type of engine is the APU?

Answer 1

2 stage, axial flow with a power section and a compressor section.

Question 2

What does the power section of the APU do?

Answer 2

Supplies necessary horsepower to drive accessory gearbox and compressor.

Question 3

What does the compressor section provide?

Answer 3

Supplies bleed air to pneumatic system for engine start and air conditioning.

Question 4

Where does the APU inlet door direct air?

Answer 4

Some to the compressor and the rest to the APU compartment for cooling.

Question 5

What RPM is required for bleed/electrical load?

Answer 5

95%

Question 6

APU start limitations

Answer 6

Max 3 starts in an hour with 2 minutes between each start. ECU prevents restart until RPM decreases to less than 7%.

Question 7

What happens when APU selected off?

Answer 7

ECU starts 60 sec cool down period. After the cool down is completed, the ECU shuts down the APU and closes the inlet door.

Question 8

How long do you have to hold the APU START switch before a start sequence initiates?

Answer 8

3 seconds.

Question 9

T/F APU has auto shutdown on the GND and in flight?

Answer 9

True

Question 10

Can the APU be operated unattended?

Answer 10

Yes

Question 11

Where can the APU be shut down from other then the cockpit?

Answer 11

External service panel (near nose gear) and in the APU compartment.