Chapter 4: Auxiliary Power Unit Flashcards
1
Q
APU Electrical Output
A
115 VAC, 40kVA, 400 Hz, 3-phase
2
Q
APU Fuel Supply Priority
A
Right main ejector pump
Left main ejector pump via cross feed valve
AC Fuel Pump 2
DC Fuel Pump
3
Q
APU Altitude Limitations
A
33,000’: APU Operation
30,000’: APU Start
21,000’: Provide bleed for engine start
15,000’: Provide bleed for ECS
4
Q
How long to wait before beginning APU start sequence?
A
30 seconds after EICAS power up
5
Q
APU Protections
A
Dedicated FADEC protects the APU from:
In Air: Overspeed, Underspeed, Critical Fault
On Ground: the above and… APU Fire, EGT Overtemp, Oil Overtemp, Low Oil Pressure, Sensor Fail
6
Q
Minimum Battery Temperature for APU Start
A
-20 C
