Oral Prep - APU Flashcards
What is the primary function of the APU?
To provide AC electrical power
What is the secondary function of the APU?
To provide pneumatic power to the 10th stage manifold system
What DC voltage is required to start the APU from battery power?
22 Volts
How is the APU fuel feed SOV opened?
When the APU PWR FUEL switchlight is pressed in (on) and BITE test is completed
Under what conditions will the APU SOV close automatically?
Automatically with a fire detected and manually when either the PWR FUEL or APU FIRE PUSH switch is pressed
What does the amber PUMP FAIL light illuminating in the APU PWR FUEL switchlight indicate?
Crossflow/APU pump has failed.
What does the amber SOV FAIL light illuminating in the APU PWR FUEL switchlight indicate?
Indicates failed APU fuel feed SOV
What does the white START light illuminating in the APU START/STOP switchlight indicate?
APU starter motor is engaged
What does the green AVAIL light illuminating in the APU PWR FUEL switchlight indicate?
APU is available for bleed air extraction
What indications are you looking for when the START/STOP switch is pressed for APU start?
Amber START light in switch illuminates, APU START status message appears, and at 50% RPM, START light and status message go out.
What 4 indications are you looking for when the APU PWR FUEL switch is pushed?
APU IN BITE status message, APU SOV OPEN status message, APU gauges appear and APU door opens.
During APU start at what RPM should the white Status APU START and the START light in the START/STOP switch/light go out?
50%
What does amber - - - to the right of the APU DOOR status indicate (on the Status page)?
APU door position is unknown.
If the APU is being used for air conditioning what are the proper bleed switch positions?
L & R 10th SOVs CLOSED, APU LCV OPEN and 10th ISOL OPEN.
When transferring the bleed source from the APU to the engines after takeoff, what is the correct switch sequence?
R 10th SOV OPEN, 10th ISOL CLOSED, L 10th SOV OPEN, APU LCV CLOSED.
