APU

Question 1

What is the primary purpose for the APU?

Answer 1

To provide electrical power.

Question 2

What is max operating altitude for the APU?

Answer 2

37,000 ft

Question 3

What is the maximum altitude for starting the APU?

Answer 3

30,000ft

Question 4

What is the max altitude for main engine starting with the APU?

Answer 4

13,000ft

Question 5

What is the max altitude for ECS operation with the APU?

Answer 5

15,000ft

Question 6

What is the difference between an APU fire in the air vs. on the ground?

Answer 6

APU will automatically shut off in both situations, but in the air, the fire bottle will have to be activated manually.

Question 7

What is maximum speed should the APU door be failed open?

Answer 7

300kts

Question 8

Will loss of oil pressure or high oil temperature result in an automatic shutdown of the APU in flight?

Answer 8

No, this only happens on the ground.

Question 9

What does the Avail switch light on the APU control panel indicate?

Answer 9

The APU is ready to accept bleed air loading.