Captains Guide-APU

Question 0

How is the APU controlled?

Answer 0

When activating the APU power switch, you are activating the ESU. The ESU controls all APU functions including start.

Question 1

Where does the APU get its fuel from?

Answer 1

APU gets fuel from left collector bay. Burn is approximately 100pph

Question 2

How is fire detected in the APU?

Answer 2

Fire is detected much like the engines, except it only has one loop. It is automatic in normal operations, but can be manually operated.

Question 3

What happens if a RBY OHT light illuminates on the APU?

Answer 3

APU malfunctions will illuminate an APU Caution light and the condition will be on the APU panel. In this case, the Rear Bay temperature is too high, APU should shut down.

Question 4

When operating the APU, what should be kept in mind during start and shutdown?

Answer 4

The APU should be “unloaded”. When powered up, two minutes after start before operating gen or bleed air
When turning off, turn off bleed air, then gen before powering down.