APU Limitations

Question 1

APU Starter Time Limits
- 1st and 2nd:
- 3rd Cycle

Answer 1

• 1st and 2nd: 60 Seconds OFF
• 3rd Cycle: 5 Minutes OFF

Question 2

APU Starting
- Min Temp:
- Max Temp:
- Max Altitude:

Answer 2

• Min Temp: -54°C
• Max Temp: ISA +39°C
• Max Altitude: 30,000 ft

Question 3

APU
- Max Altitude for Operation:
- Max Altitude for Bleed:
- Max Altitude to Assist Engine Start:

Answer 3

• Max Altitude for Operation: 33,000 ft
• Max Altitude for Bleed: 15,000 ft
• Max Altitude to Assist Engine Start: 21,000 ft

Question 4

APU
- Max Rotor Speed:

Answer 4

• Max Rotor Speed: 108%

Question 5

APU
-Max EGT Start:
-Max EGT Continuous:

• Does the APU automatically shutdown if EGT limits are exceeded?
• Is there a time limit for operating in the Amber range?

Answer 5

-Max EGT Start: 1032°C
-Max EGT Continuous: 717°C

• In flight there is NO automatic shutdown if EGT exceeds limits.
• There is NO time limitation for operating the APU on the ground or in flight in the Amber range between 662°C and 717°C.

Question 6

• The Minimum Battery #2 Temperature for APU Starting is ____.
• Note:

Answer 6

• The Minimum Battery #2 Temperature for APU Starting is -20°C.
• Note: this does not prevent starting the APU via DC Power if a DC GPU is available and utilized.