APU Flashcards
What happens when you push in the PWR/FUEL button?
- Starts APU Fuel pump
- Opens FUEL & NEG G SOVs
- Displays APU RPM & EGT on EICAS
When will the green AVAIL light come on?
95% + 4 seconds
Except for fire, how do you determine why the APU auto-shutdown?
APU trip indicators on the APU fault panel
Why do you wait 5 seconds to push the APU FIRE BOTTLE?
To give flapper valve on APU enclosure time to close.
Is APU bleed air & electric allowed at the same time in flight?
Yes
150
Recommended waiting period before selecting APU air?
2 minutes
How many APU consecutive start attempts?
3
Which APU auto-shutdowns do not have an EICAS message?
- UNDERSPEED
- LOSS of EGT SENSOR
- ECU FAIL
150
APU generator maximum load?
30kVA to 20,000’
APU Electronic Control Unit (ECU)…
- Sets fuel & temp schedules
- Transmits data to EICAS
- Transmits data to the APU fault panel
The APU supplies bleed air to…
10th Stage only
APU battery starts?
3 starts, 30 second crank followed by 20-minue wait
Amber APU SOV EICAS steps…
Call for APU SOV checklist
APU model
Honeywell 3G-150 (CL)
When to check APU oil?
Min 30 minutes post shutdown
APU fuel comes from…
Normal fuel, right tank
Secondary fuel, left tank (no cooling)
APU Fuel pump inop?
Secondary fuel 10 minute APU ops
APU Fuel Pump power source?
DC BATT BUS
APU Fire
- APU & NEG G SOV - closed
- APU SOV CLSD – EICAS message
APU Battery
24 VDC
43 amp hour
22 V to start APU
APU Hung Start
<30% w/in 60 seconds
APU 2nd engine start?
Running engine 70% N2 max
