APU

Question 1

What are the APU parameters in the STATUS page?

Answer 1

EGT, N1, N2, APU oil quantity, RF/LO.

Question 2

What type of starter is used to start the APU and what power is used?

Answer 2

APU DC electrical starter.

24 volt APU battery.

Question 3

What APU equipment is supplied by the APU battery?

Answer 3

• Inlet door
• APU controller
• DC fuel pump
• APU fire detection system

Question 4

What APU equipment is supplied by the main battery?

Answer 4

• APU fire extinguisher
• APU fuel valve
• Standby power for the APU controller.

Question 5

During start, which APU components are powered by the main battery?

Answer 5

All APU components except the starter are supplied by the main battery while APU start engaged.

Question 6

What is the air/ground inhibit for APU starting?

Answer 6

APU can only be started on the ground.

Question 7

When will the ALU starter engage during start?

Answer 7

Starter engages when APU door fully open.

Question 8

What conditions will cause the EICAS memo message APU RUNNING to be displayed?

Answer 8

APU selection is ON and APU N1 exceeds 95%.

Question 9

How long does the APU need to cool down during a normal shutdown?

Answer 9

60 seconds.

Question 10

How long should the battery switch be left ON after APU is shutdown?

Answer 10

2 minutes.

Question 11

What will cause the APU to shut down immediately without the cooling cycle?

Answer 11

If a limit is exceeded or a fire is detected.

Question 12

What conditions will cause the EICAS message APU to be displayed?

Answer 12

Automatic shut down of the APU with the APU selector ON.

APU N1 exceeds 95% with APU selector OFF.