FCOM

Question 1

The basic element of the APU is a

Answer 1

single-shaft gas turbine that delivers mechanical shafts power for driving the accessory gearbox(electrical generator, starter) and produces bleed air

Question 2

What is ECB

Answer 2

Electronic Control Box a full authority digital electronic controller

Question 3

What ECB controlles

Answer 3

• Sequences the start and monitors it
• Monitors speed and temperature
• Monitors bleed air
• Sequences the shutdown
• Controls the automatic shutdown

Question 4

Which fuel line supplies the APU

Answer 4

The let fuel feed line supplies the APU

Question 5

What is IGV

Answer 5

Inlet Guide Vanes control bleed air flow, and a fuel-pressure-powered actuator positions the IGVs

Question 6

What is APU speed

Answer 6

APU speed is always 100% except for air conditioning

Question 7

The APU speed is 99% if the ambient temperature is

Answer 7

above -18’C or below 35’C

Question 8

If the aircraft was using APU bleed air, the APU keeps running for cooling period of

Answer 8

60 Seconds

Question 9

At what % the air inlet flap closes

Answer 9

7%

Question 10

When AVAIL green light comes on

Answer 10

when N is above 99.5% or 2 seconds after N reaches 95%

Question 11

APU N amber when

Answer 11

N >= 102%

Question 12

APU N red when

Answer 12

N >= 107%

Question 13

APU EGT amber when

Answer 13

EGT >= EGT max -33’C

Question 14

APU EGT red when

Answer 14

EGT >= EGT max

Question 15

Maximum EGT during start

Answer 15

1090’C

Question 16

Maximum EGT with APU running

Answer 16

675’C

Question 17

Will the APU shutdown automatically in the event of a fire in flight?

Answer 17

No, only on the ground.

In flight, the APU must be shut down manually and the agent manually discharged

Question 18

What if the aircraft is on the ground and a APU fire is detected?

Answer 18

The APU will automatically shutdown and discharge agent 3 seconds after the fire warning.
A FAULT light with a squib DISCH light would indicate an auto shutdown for a fire

Question 19

Will an APU fire detection system test shut the APU down?

Answer 19

No, but the APU auto extinguisher test will

Question 20

What is the relationship between the APU bleed valve, the cross bleed valve and the engine bleed valves?

Answer 20

The position of the APU bleed valve controls the cross-bleed valve (If the switch is in AUTO) and the engine bleed valves. If the APU valve is opened, the cross-bleed valve is opened and engine valves are closed

Question 21

Why does the green APU AVAIL light remain lighted and the APU generator continue to power the buses after the Master switch is selected OFF?

Answer 21

If the APU bleed valve has been open, the APU will continue to run at reduced RPM for up to two minutes to cool the turbine after Master switch is selected off

Question 22

What are the APU operating limits?

Answer 22

Remember 15,20,25 and 39
The APU will operate 2 packs to 15,000
1 Pack to 20,000
Battery only APU starts arent allowed above 25,000
Ceiling of 39,000
20,000 is the top of the APU assisted air-start envelop for the engines (if airspeed is < 200kts)

Question 23

What the cooling period between APU starts?

Answer 23

1 minute cooling period between start attempts and a 1 hour delay after the third start attempts

Question 24

Can the APU be used with wing anti-ice on?

Answer 24

Yest, but only for electrical power

APU bleed valve should not be opened while using wing anti-ice

Question 25

What does a FAULT light in the APU Bleed Switch indicate?

Answer 25

An APU bleed air leak. it will be accompanied by ECAM action to ensure the APU bleed valve is closed

Question 26

What does the APU MASTER SW do?

Answer 26

When selected ON, the

• ECB power up test is initiated
• APU air inlet flap opens
• APU fuel isolation valve opens
• APU fuel pump runs
• ECAM APU page is displayed

Question 27

APU fuel burn is

Answer 27

290 pounds per hour using both bleed air and the generator

Question 28

LOW OIL LEVEL indicated the remaining oil quantity allows for normal operation of

Answer 28

approximately 10 hours