APU

Question 1

True or False: A dedicated FADEC controls the APU.

Answer 1

True

Question 2

What power sources can be used to start the APU?

Answer 2

DC GPU or BATT 2 (5.14 Vol 2)

Question 3

Fuel for the APU can be provided by the _______ tank through the crossfeed
Valve.

Answer 3

left

Question 4

Which fuel tank usually provides the APU with fuel during normal operations?

Answer 4

Right

Question 5

The _______ provides control of the APU bleed air operations

Answer 5

AMS controller

(Air Management System)

Question 6

The APU can provide AC electrical power up to __________ ft.

Answer 6

33,000 ft

[start up to 30,000 ft, bleed air for engine start up to 21,000 ft, bleed for air up to 15,000 ft]

Question 7

True or False: APU bleed control is located on the APU control panel.

Answer 7

False

Question 8

True or False: The APU will auto shutdown while airborne for a high oil
temperature condition.

Answer 8

False

Question 9

The APU cooldown period prior to shutdown is _____.

Answer 9

1 min.

Question 10

True or False: The APU will auto shutdown on the ground for a low oil pressure
Condition.

Answer 10

True

Question 11

After the spool-down period of the APU is over, the EICAS message APU
SHUTTING DOWN will _______.

Answer 11

dissapear / Be removed

Question 12

True or False: Selecting the APU control knob to OFF shuts down the APU.

Answer 12

True

Question 13

True or False: The APU can be shut down using the emergency shutdown button,
but will take 1 minute to cool down.

Answer 13

False [without the 1 min cooldown]

Question 14

True or False: The APU is controlled by the left engine’s FADEC.

Answer 14

False

Question 15

If OFF is selected while the APU is running, the shutdown sequence _______.

Answer 15

Is initiated

can be canceled if the knob is reselected to ON within the 1-minute cooldown period

Question 16

True or False: The APU must be shut down before every takeoff.

Answer 16

False (ON for ECS OFF takeoff 2.10.1 Vol 1)

Question 17

When are electrical and pneumatic loading available during an APU start?

Answer 17

3 sec. After the APU has reached 95% RPM

Question 18

True or False: During the normal shutdown sequence, APU bleed air is
immediately stopped and electrical power is removed after a 1-minute cooldown
period, followed by a spool-down period.

Answer 18

True

Question 19

In flight, the APU automatically shuts down for which of the following conditions?

Answer 19

Overspeed,

underspeed,

FADEC Critical Fault

Question 20

True or False: If BATT 2 is below temperature limits, AC external power can be
used to start the APU.

Answer 20

False (DC GPU 5.14 Vol 2)

Question 21

During an APU fire, what will occur if the APU fire extinguisher button is pressed
without first pressing the APU EMER STOP button?

Answer 21

Halon would be exhausted because the APU is still spinning!

closes the APU fuel shutoff valve (SOV),

Discharges the APU fire bottle,

displays an “APU FIREX BTL DISCH” EICAS advisory message (7.5 Vol 2)