APU Flashcards

1
Q

APU gas turbine generator

  • what kind of power does it supply
  • limitation on bleed air
  • how is it controlled
  • limitation while deicing
A
  • DC Power - 28vDC, 400 amps (ground operations only)
  • Provides Bleed Air for “Air Conditioning Packs” (ground operations only)
  • Controlled by its own FADEC
  • Can NOT de-ice with APU ON (on ground)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

APU Fuel Supply

  • where is fuel fed from
  • what button opens the APU fuel sov and when will it close
  • the APU fuel sov will close automatically if any of the following occur (7)
A
  • Fuel is fed from the LEFT wing fuel collector bay
  • APU fuel shutoff valve OPENS when the APU PWR switchlight is pushed and CLOSES when the APU is shut down
  • The APU fuel shutoff valve will automatically close if any of the following should occur:
    • The PWR switchlight is pushed off
    • An APU fire is detected
    • EXTG switchlight on the APU section of the Fire Protection Panel is pushed
    • APU FIRE TEST button is pushed
    • Aircraft becomes airborne while the APU is still running
    • An APU fault is detected
    • Starter-Generator overheats (the GEN OHT advisory light illuminates)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

APU Electrical System

  • what voltage is the generator and where is it mounted
  • what power is needed for a start
  • to what % will the started remain engaged
A
  • 28vDC Generator mounted on the APU Gearbox
  • APU start requires either aircraft battery power or an external DC power source
  • Starter mode remains engaged until the APU reaches 50% operating speed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

APU bleed air

- Provides bleed air for: (2)

A
  • ECS (ground operations only)

- Holds the “Aft Safety Valve’ Open (ground operations only)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

APU FADEC

- The FADEC monitors critical/major faults and will command shutdown based on: (9)

A
  • Overspeed
  • Underspeed
  • Start Failure
  • Acceleration Failure
  • EGT Overtemperature
  • High Oil Temperature
  • Low Oil pressure
  • Failed Sensors
  • Internal Failure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly