APU

Question 1

When should APU be started?

Answer 1

10 min prior to pushback

Except with COVID it should be on for ventilation on boarding and deplaning

Question 2

What happens when you turn off the APU?

Answer 2

APU bleed IMMEDIATLY closes

Generator use for 1 minute and the FADEC shuts down APU

Question 3

APU can get fuel from where?

Answer 3

ACFP 2
DCFP
Engine 2 Ejector pump

Question 4

Do you have to have both batteries for an APU start?

Answer 4

Battery 1 yes

Battery 2 no, can be substituted with DC GPU

Question 5

When will the APU shutdown automatically?

Answer 5

Ground:
Underspeed
Overspeed
FADEC critical fault
Flight:
Underspeed
Overspeed
FADEC critical fault
Sensor error
High oil temp
EGT
Low oil press
Fire

Question 6

How long should you wait after shutting down the APU?

Answer 6

80 sec, for the APU SOV CLOSED EICAS message

Question 7

APU Emergency stop?

Answer 7

Closes APU FUEL SOV

If there is a fire detected the top will light up

Question 8

Features for system 3 during RAT deploy

Answer 8

Flow limiter (RAT deploy)-reduce the amount of flow during RAT deploy
Pump unloader (start up)-reduces discharge pressure