APU

Question 1

What is the APU guaranteed starting envelope?

Answer 1

15,000 feet and below

250 Kts max

Question 2

What conditions will cause automatic shut down of the APU?

Answer 2

• APU fire
• high EGT
• high oil temperature
• low oil pressure
• over current in the ECU.

Question 3

Upon detection of a fire in the APU, will the fire extinquisher discharge automatically?

Answer 3

NO. The APU fire extinguisher must be manually discharged by lifting the guard and depressing
the APU Fire Ext Switch.

Question 4

After an APU start, when will the APU Load Control Valve, allow the APU air for engine start and pack operation?

Answer 4

APU air is available after the APU RPM has reached an operating speed of 95% rpm for 4 seconds and EGT has stabilized for 2 minutes.

Question 5

From which Fuel Tank can the APU receive fuel?

Answer 5

• Fuel is drawn from the Left Wing Fuel Hopper using the Left Main and/or Left Alternate Fuel Pumps
• Fuel can be drawn through the Crossflow Valve using the Right Main and/or Right Alternate Fuel Pumps

Question 6

Max EGT APU running

Answer 6

732 degrees C

Question 7

Max EGT with APU air on

Answer 7

680 degrees C

Question 8

APU Operating RPM

Answer 8

100% +- 3%

Question 9

APU Over speed RPM

Answer 9

110%%