APU Flashcards
Where is the APU situated?
In a fire proof enclosure at the rear fuselage at of the rear pressure bulkhead.
What tank does the fuel normally come from?
Left collector tank.
What electrical power is used for operation?
DC
What can the APU supply?
Bleed air and AC electrical power on ground
Inflight, electrical power only.
How do you start it?
Battery on. Check fire agent. Using Start button and releasing. (on RR place in ON for 15 seconds then start).
What does the AVAIL light tell you?
electrical power is available
bleed are is available after 2mins
APU: When is bleed air available after start?
2mins after AVAIL light comes on.
What faults will shutdown the APU in flight and what indications do you get?
Fire or APU over speed. If start sequence takes more then 90secs
What faults will shutdown the APU on the ground and what indications do you get?
Fire or APU over speed, plus low oil pressure, high oil pressure, high exhaust gas temp. and other internal APU failures.
What happens if the APU load becomes excessive?
it decreases bleed air.
May the APU operate unattended in the ground and why?
Yes, due to continuous self test feature on ground. Plus auto fire system
What can you do to enhance cabin cooling after landing in hot climates?
Turn APU on shortly before before landing.
When is it recommended that you leave the APU running for a flight?
As per MELed
Where and when is the APU page displayed?
can be manually or automatically displayed in some AIRCRAFT MFDU if AC buses are energized. Manual is via APU p/b on MFDS panel. APU page is automatically displayed when start switch is selected from OFF to ON, during APU start or if a APU parameter (EGT or RPM) exceeds its limit.
