APU

Question 1

What information should be entered on the −13 if the APU start is not completed or the APU
is automatically shut down?

Answer 1

Use the BITE (BUILT IN TEST EQUIPMENT) codes on the DESU

Question 2

What action should you take if the UTIL PRESS Light has not gone out within 30 seconds
after the APU RDY Light comes on?

Answer 2

Shut off the APU

Question 3

What 3 accessories are driven by the APU’s reduction drive?

Answer 3

Motor/pump, APU gen, and fuel control

Question 4

Sequencing and monitoring of the APU start and operation are accomplished through what
component?

Answer 4

DESU

Question 5

What restriction is placed on APU operation during flight?

Answer 5

Only use in emergencies

Question 6

How long do you delay in the RUN position before going to START?

Answer 6

5 seconds

Question 7

What does the APU RDY Light indicate?

Answer 7

The APU is turning at speed of 90-110% with appropriate temp

Question 8

What information does the magnetic pickup send to the DESU?

Answer 8

Sends the speed signal to the DESU

Question 9

When the APU is shut down, how long should you wait before attempting a restart?

Answer 9

1 minute

Question 10

What component provides fuel to the APU Fuel Control?

Answer 10

Fuel boost pump

Question 11

What two components on the APU provide a constant signal to the DESU

Answer 11

The magnetic pick up and the exhaust gas temp probe

Question 12

name the 4 APU sections

Answer 12

A: intake
B: compressor (gas generator)
C: comustion chamber (power turbine)
D: exhaust

Question 13

Identify all APU accesories

Answer 13

A: APU
B: Accessory gearbox
C: Fuel control
D: Motor pump
E: A/C generator