10. APU Panel (APU)

Question 1

What does the illumination APU MASTER SW FAULT indicate?

Answer 1

Automatic APU shutdown has occurred

Question 2

What is the significance of the APU AVAIL light illuminating?

Answer 2

APU is running above 99.5 % or 2 seconds after N speed reaching 95%. In practical terms it is ready to accept and support ELEC and/or AIR load.

Question 3

What condition in the APU system would cause an external horn to sound on the ground?

Answer 3

APU fire

Question 4

With the APU green AVAIL light ON and the EXT PWR green AVAIL light on, which system is powering the aircraft?

Answer 4

2 Avails = APU powering the aircraft

Question 5

If possible, how would the APU be used if it has already started the cooldown cycle?

Answer 5

Pressing the APU MASTER SW pushbutton

Question 6

When running the securing checklist why is it important to wait 2 minutes after the APU avail light goes out before switching off the batteries?

Answer 6

Switching the batteries off before the APU flap is closed may cause smoke in the cabin during the next flight.

Question 7

If one generator fails, what is the maximum altitude that you can start the APU?

Answer 7

FL 410

Question 8

If your aircraft is in an emergency electrical configuration, what is the maximum altitude to start the APU?

Answer 8

FL 250