APU

Question 1

Max altitude for APU start? (Normal aircraft operation).

Answer 1

39,000’

Question 2

Can we use the APU Bleed at 39,000 ft?

Answer 2

No APU Bleed at the max ceiling limit. APU only only supplies electrical power at the max ceiling limit. No APU Bleed until 22,500 ft for pressurization and 20,000 ft for 1 engine restart assist

Question 5

Max APU start using batteries only to provide electric supply to the aircraft in flight?

Answer 5

25,000 ft

Question 6

Max APU for electric and 1 pack for airconditioning?

Why is this useful for Emergency Descent?

Answer 6

FL225. This is used for Emergency Descent, if Dual Engine Bleed Fault, starting the APU Bleed at FL250/225 ends the Emergency Descent. No point for APU Bleed if dual Bleed leaks or both Packs are inoperative

Question 7

Max APU bleed 1 pack for engine start in flight?

Answer 7

20,000 ft

Question 8

Max APU 2 packs for engine start in flight?

Answer 8

15,000 ft

Question 13

Min APU oil quantity before start?

Answer 13

LOW OIL LEVEL not displayed

Question 14

APU operation with “Low Oil Level” displayed?

Answer 14

10 hours

Question 15

APU re-start cycle?

Answer 15

3 on / 60 mins off / 3 on

Question 16

APU Max N?

Answer 16

107 %

Question 17

Max APU EGT with APU running?

Answer 17

675 degC

Question 18

APU Max EGT starting below 35,000 ft?

Answer 18

1,090 degC

Question 19

APU Max EGT starting above 35,000 ft?

Answer 19

1120 degC