APU

Question 1

What causes an automatic EMER SHUTDOWN of the APU?

When is this facility available?

Answer 1

• APU FIRE

- On the GROUND ONLY!!!

Question 2

Why would the APU continue to run after being selected to OFF?

Answer 2

To cool down if bleed was supplied (60 sec)

Question 3

What happens if excessive APU EGT is sensed?

Answer 3

• AUTO SHUTDOWN

- FAULT comes on

Question 4

APU AUTO SHUTDOWN is available during which phases of flight?

And EMER SHUTDOWN (fire)

Answer 4

• All phases

- On the ground only so phases 1, 2, 9 and 10

Question 5

What causes the APU FLAP to open?

What does the message FLAP OPEN mean exactly?

Answer 5

• Pushing the APU MSTR Switch

- APU AIR-INTAKE is fully OPEN

Question 6

What happens if the APU START button is pressed immediately after pressing the APU MSTR switch?

Answer 6

Start sequence is delayed until the flap is fully open

Question 7

APU AVAIL message signifies what?

Answer 7

APU N > 95%

Question 8

What is the maximum start altitude for the APU?

Answer 8

41. 000 feet to start from AC

25. 000 feet for a BAT Start

Question 9

What are the altitude restrictions for APU BLEED & PACKS use?

Answer 9

Bleed + 1 Pack = 22.500 feet

Bleed + 2 Pack = 15.000 feet

Question 10

What should you do when the LO OIL LVL associated with the APU shows on the SD?

Answer 10

• Note it in the TECH LOG
• Use it as normal but maintenance action is required within 10 hours of operating time (so time the APU use and note it down)