APU

Question 1

What is the indication the APU gen is operating at speed and not powering the bus?

Answer 1

Blue APU GEN OFF BUS

Question 2

The MAINT light illuminates with the APU running, what does this indicate?

Answer 2

A maintenance problem exists. APU can still operate as per normal

Question 3

With AC fuel pumps running, where is the APU fuel supplied from?

Answer 3

The left side of the fuel manifold

Question 4

What services can the APU supply?

Answer 4

Bleed air for both air conditioning packs on the ground or one pack in flight and both transfer buses whether in flight or on the ground.

Question 5

Under what circumstances could the APU OVERSPEED warning light illuminate?

Answer 5

APU rpm limit has been exceeded resulting in an automatic shutdown or a fault has been detected in the over speed system during APU shutdown.

Question 6

How is fuel supplied to the APU?

Answer 6

Operate an AC pump. If not, the APU will suction feed from the left fuel tank(main)

Question 7

How long to wait after getting APU GEN OFF BUS light after started APU to putting bleed load on?

Answer 7

2 minutes (Boeing SOP 1 minute)

Question 8

With no AC power to aircraft, what power supply is used to start APU

Answer 8

Battery

Question 9

What would happen to the APU (running) if the battery switch was switched OFF

Answer 9

It would shut down due to loss of power to its electronc control unit

Question 10

What would be result of an APU EGT exceedance during start?

Answer 10

It would shut down