APU Flashcards
APU voltage to start
22 volts min
24 volts recommended
If APU is on fire can auto shutdown be interrupted
Yes if fire bell alarm is canceled within 10 seconds on the ground
When APU is running on the ground fire bell button
Should not be held for more than 10 seconds because APU will auto shutdown
APU will auto shutdown on the ground due to
Overvoltage
Overcurrent
Overspeed
High Oil Temp
Loss of oil pressure
Loss of EGT, ECU, Speed sensors
APU will auto shutdown in the air due to
Overspeed
Overvoltage
Which fuel tank APU feeds from
Right tank, can be crossfed from the left
APU starting speed and altitude
200 KIAS, 20,000 ft. Vary with altitude and speed
Why do we move SHUTOFF/EXT to CLOSE during APU fire
To verify CLOSED light illuminated and fuel is not feeding to the APU
Electrical power priority
MAIN GEN, GPU, APU
Starter contactor light should extinguish at what RPM
50%
Will main generator carry all the load during start of a second engine with APU gen ON
No, APU GEN and MAIN GEN share the load however, only MAIN GEN is powering CENTRAL DC bus
What APU dos our aircraft have
Garret Turbine Engine Company
How much HP does the APU have
25SHP
What does the APU use for cooling on the ground
APU has a ground cooling fan attached to starter generator
What is the fuel burn of the APU with generator running and the bleeds open
100lbs/hr + 30% = 130lbs/hr
At what RPM does APU overspeed
110%
What happens when you press APU shutoff button
Simulates Overpeed
What does the ABLE light indicate on APU
Fire extinguisher bottle is good to use and squib is in good condition
The APU provide a source of
Pneumatic power
Electric Power
During the APU start what commands APU starter disengagment
ECU
