APU

Question 1

Can the APU be used for pressurization in flight?

Answer 1

No.

Question 2

APU 36-150(G) max EGT limitations:

Answer 2

• 973°C from 0-50%
• 973-732°C from 51-87% (linear)
• 732°C 87-100%
• 732°C normal running
• 680°C running with APU air on

Question 3

Max APU speed? (Rotor speed?)

Answer 3

110%

Question 4

APU starting limits with airplane battery?

Answer 4

3 - 30 sec attempts / 20 min. off
3 - 30 sec attempts / 1 hour off

Question 5

APU starting limits with external DC battery?

Answer 5

2 - 15 sec attempts / 20 min. off
2 - 15 sec attempts / 1 hour off

Question 6

What are APU start limits? (# per hour?)

Answer 6

6, at 10 min. interval

Question 7

APU start envelope?

Answer 7

Guaranteed from SL to 15,000 feet at 250 kts.

Question 8

APU flight operating limits?

Answer 8

Inspect within 10 APU hours if operated 1 hour above FL300 or 5 times above FL350

Question 9

Can APU be operated unattended?

Answer 9

No. (per AD 201720-08) No unattended APU ground operations. APU can only be used in flight with dual and single engine failure or dual or single alternator / converter failure. Dispatch is not permitted with any alternator and/or converter inoperative.