Engines and APU

Question 1

Max altitude for inflight APU start?

Answer 1

Max certified altitude

Question 2

APU bleed air available up to what altitude?

Answer 2

17000ft

Question 3

What two batteries are required for APU start?

Answer 3

APU battery and aircraft main battery

Question 4

What fuel manifold provides fuel to APU?

Answer 4

Left fuel manifold

Question 5

What is fuel pumps and power sources used for APU fuel? (2)

Answer 5

1. Dedicated DC fuel pump if no AC power available and APU selector placed to on
2. When AC power is available then uses left forward AC fuel pump regardless of if switch is turned on

Question 6

How is APU unit protected from thermal shock on shutdown?

Answer 6

Time delay allowing for cooldown (shuts down straight away if APU bleed valve been closed for a while, if not it delays shutdown)

Question 7

How cancel the APU shutdown if switch inadvertently moved to off (and run light still on)?

Answer 7

Momentarily move selector to start cancels the shutdown

Question 8

What happens to APU on the ground if battery switch moved to off? Why need to be careful?
In flight?

Answer 8

APU will shutdown after cooldown period but no fire detection will be available prior to shutdown
In flight it will not shut down APU

Question 9

What does amber FAULT light on APU mean and how reset the fault circuitry?

Answer 9

Fault is sensed and APU will shut down immediately

Reset by moving APU selector to OFF

Question 10

When does APU Fault light momentarily come on for normal operations?

Answer 10

When APU fuel valve is not in commanded position so therefore during start and shutdown it comes on momentarily

Question 11

Two main services provided by APU?

Answer 11

Electrics and pneumatics.

Question 12

Where is the external APU control panel?

Answer 12

On nose wheel strut

Question 13

If you see APU FUEL VALVE on EICAS should you attempt APU start?

Answer 13

No

Question 14

If the APU experiences a FAULT on start can you attempt one restart?

Answer 14

Yes, provided fault light extinguishes when moved to OFF before attempting next start

Question 15

What EGT should you wait for (motoring) during start before you put fuel on?

Answer 15

100deg C EGT

Question 16

What % N3 does starter cut out occur?

Answer 16

47% N3

Question 17

Light off should occur how long after fuel on during start?

Answer 17

20sec

Question 18

N3 should be stabilised within how many seconds of start?

Answer 18

90sec

Question 19

In AUTO position, when do ignitors come on? (2)

Answer 19

When engine anti ice is turned on or flaps out of the up position

Question 20

Two occasions when continuous ignition is used?

Answer 20

• Heavy rain

- Severe turbulence

Question 21

Difference between CONT and FLT positions on ignition switch?

Answer 21

Cont is continuous for just one ignitor, FLT is for both ignitors

Question 22

Which inflight start envelopes are given?

Answer 22

The one closest to current flight level and next two down

Question 23

What does x-bleed above N3 mean for inflight start?

Answer 23

Means x-bleed from live engine is required

Question 24

What does l or R STARTER CUTOUT mean and actions?

Answer 24

Start valve has not closed at 47% N3, starter remains in GND, and starter must be moved manually to Auto

Question 25

What must happen before you can move from reverse idle to full reverse thrust on the reverse levers?

Answer 25

Reversers must have moved to the open position

Question 26

What two additional two things does moving the reverse thrust levers to reverse idle do on landing?

Answer 26

1. Disengages auto throttle

2. Deploys the speedbrake