APU Flashcards
What controls the APU?
A dedicated FADEC
How are the batteries uses for APU start?
BATT 2 powers the starter, BATT 1 powers the FADEC and EICAS for monitoring
What is the fuel source for the APU?
- right fuel tank
- left tank through the crossfeed valve
What fuel pump is used for APU start when only battery power is available?
DC fuel pump, right side
What fuel pump is used to start the APU when AC power is available?
ACMP 2
What pump is used to start the APU when the right engine is running?
Right ejector fuel pump
Will the APU shut down automatically if speed and and acceleration rate is reached in the starting cycle time?
Yes
What does moving the APU start switch to OFF do?
- initiates APU shutdown
- one minute cooldown
- no pneumatics, electrics only for one minute
Can the APU shutdown sequence be cancelled?
Yes. Move the APU start switch to ON before the end of the one-minute cooldown
When will auto shutdown of the APU occur when on the ground?
- overspeed
- underspeed
- FADEC critical fault
- fire
- overtemp
- low oil pressure
- sensor fail
When will the APU automatically shut down when in flight?
- overspeed
- underspeed
- FADEC critical fault
Can the APU be started after a critical fault?
No
