Aux Power Unit

Question 1

APU located

Answer 1

Tailcone of airplane with air inlet right side and the Exhaust on the left side

Question 2

APU operating altitude

Answer 2

Max altitude of the 777 43100

Question 3

Bleed air output

Answer 3

Decreases as Altitude increases and availability of bleed air up to FL220

Question 4

ATS-Air turbine starter

Answer 4

Powers APU and bleed air rotates the ATS

Question 5

Bleed air not available for ATS

Answer 5

Electric starter used

Dedicated battery for starter

Question 6

Main AC battery power required for APU

Answer 6

To operate
APU inlet door
Fuel valve
Fire detection system

Question 7

During APU Start

Answer 7

APU inlet door opens
Left forward A-C fuel pump or the DC pump is energised
Fuel valve opens
If sufficient bleed air, bleed air duct opens and drives ATS
APU running msg in white
APU parameters on status display

Question 8

APU Shutdown

Answer 8

Cool down msg and all doors close then APU msg gone fault light is there momentarily

Question 9

APU limit msg

Answer 9

Either 
High EGT
Low oil pressure
High oil temp
Fault light

Question 10

APU amber shutdown msg in flight

Answer 10

Auto shutdown

Fault or fire

Question 11

APU Feature in flight

Answer 11

In the unlikely event of all generators and backup generators failing in flight
Both AC power buses to lose power
APU is automatically switched on even if APU selector is in off position