APU

Question 1

What outputs and usage does the APU provide?

Answer 1

Electrical power (APU GEN, starter, etc) and bleed air (engine starting, air conditioning, etc)

Question 2

When will the APU fuel pump start automatically?

Answer 2

The APU fuel pump will start automatically when fuel pressure is not available, due to a battery only start or if the fuel pumps are switch off.

Question 3

What normally supplies the APU with fuel

Answer 3

The left fuel feed line

Question 4

What % N is AMBER

Answer 4

102%

Question 5

What % N is RED

Answer 5

107%

Question 6

What controls the APU

Answer 6

ECB

Electronic Control Box

Monitors: speed, temperature, start and shutdown sequences

Question 7

How long must crew wait following three unsuccessful APU start attempts

Answer 7

60 minutes before any further start attempts

Question 8

Max allowable EGT for the APU?

Answer 8

675°C

Question 9

What will happen on the ground with the APU running, if a fire is detected in the APU compartment?

Answer 9

APU fire warnings operate in cockpit, a horn sounds in the nose gear bay, the APU AVAIL light goes out, a FAULT light illuminates in the APU MASTER pb-sw, the APU shuts down and the APU fire extinguisher automatically discharges

Question 10

In an emergency what two ways can the APU be shut down?

Answer 10

By pushing the APU FIRE pb in the flight deck or the APU SHUT OFF on the interphone panel.

Question 11

Why wait between APU MASTER ON and APU START pb ON?

Answer 11

Wait 3 seconds to allow the door to open

Question 12

Why wait between APU START and APU BLEED?

Answer 12

3 minutes on first flight of the day

Prevents smells in the cabin caused by oil/cool seals

Question 13

Max altitude for APU use?

Answer 13

39,800ft

Question 14

Max altitude for APU engine start assist

Answer 14

20,000ft

Question 15

Max altitude for wing anti ice?

Answer 15

Trick question: not used for wing anti ice!!