APU

Question 1

Which of the following statements is true?

Answer 1

Left FWD AC fuel boost pump is used when AC ground service power is available and APU DC fuel pump is used when no AC power is available

Question 2

Which of these items is required for an APU start?

Answer 2

APU and; main batteries

Question 3

Under what circumstances does no cooldown delay occur during the APU shutdown sequence?

Answer 3

If the bleed air valve is closed for more than 60 sec. before the APU selector is positioned to OFF

Question 4

What happens to the APU FAULT light when the APU selector is placed to ON or START?

Answer 4

Illuminates until the fuel valve is open

Question 5

What is the maximum altitude for operating the APU?

Answer 5

Airplane ceiling

Question 6

What is the APU time delay feature for cooling?

Answer 6

Approximately 60 seconds after bleed valve has been closed (between 0 and 120 sec.)

Question 7

APU selector is ON. APU FAULT amber light on the EICAS. FAULT amber light on the APU Selector Panel. What are the implications of these fault indications

Answer 7

General APU malfunction; APU shuts down

Question 8

Which of the following describes the START position of the APU selector?

Answer 8

Momentary. Returns to ON when released

Question 9

The APU selector has been inadvertently moved to OFF and the APU RUN light is still illuminated. How can the shutdown cycle be cancelled?

Answer 9

Move the APU selector to START and then release to ON

Question 10

What can the APU FAULT light indicate?

Answer 10

APU fuel valve NOT in commanded position

Question 11

What is the normal sequence of events when the APU selector is turned off?

Answer 11

The engine bleed air valves close, then after 60 seconds the APU fuel valve closes

Question 12

How can an APU fault be reset?

Answer 12

Only by moving APU selector to OFF

Question 13

The average APU fuel consumption is:

Answer 13

115 kg / h (ground) & 90 kg (flight)

Question 14

What is indicated by an illuminated FAULT light when the APU selector is OFF?

Answer 14

Fuel valve did not close

Question 15

The fuel for APU operation normally comes from which fuel tank?

Answer 15

Left main fuel tank

Question 16

What is the minimum power needed to start and operate the APU?

Answer 16

APU battery and main battery

Question 17

On ground, if you switch off the battery while the APU is running:

Answer 17

APU Shutdown with delay protection but without FIRE DETECTION

Question 18

What does the APU FUEL VAL advisory mean?

Answer 18

The fuel valve is not in the signaled position

Question 19

APU battery supplies power to:

Answer 19

Starter, air inlet door and APU control circuitry

Question 20

When does the APU cool down timing delay begin?

Answer 20

When the APU bleed air valve closes

Question 21

Why is a cooldown delay needed in the APU shutdown sequence?

Answer 21

To protect the APU from thermal shock.

Question 22

APU is a single shaft gas turbine located in the unpressurized tailcone

Answer 22

True

Question 23

What is cut off first when the APU selector is moved to OFF

Answer 23

Bleed air

Question 24

No fire system test is required before starting the APU.

Answer 24

True

Question 25

What does continuous illumination of the APU RUN light indicate?

Answer 25

APU is at operating speed.

Question 26

The APU selector is moved from OFF to START and released to ON. When does the starter engage?

Answer 26

When the inlet door has fully opened

Question 27

Which is true statement regarding the APU?

Answer 27

The APU can supply electrical power for all normal loads plus bleed air for 2 air conditioning packs or start an engine

Question 28

When will moving the battery switch OFF cause the APU to shut down?

Answer 28

On the ground only