737 APU Control Panel

Question 1

Overhead. APU GEN OFF BUS

Answer 1

APU GEN OFF BUS

Shows APU is running (at 95%) but its generator is not a power source in use.

Question 2

Overhead - APU Control Panel

Answer 2

• A malfunction exists which causes APU to auto shut down.
• Shows that APU ECU sensed a fault and auto shut down.
• Light will illuminate when APU switched is placed to OFF. Extinguishes after 5 min.

Question 3

Overhead - APU Control Panel - LOW OIL PRESS

Answer 3

Illuminates when oil press is low. (No shit)

Auto shutdown in 20 sec.

Extinguishes after 5 minutes from APU shut off.

Question 4

Overhead APU MAINT

Answer 4

Indicates Low oil quantity, or starter-generator has a shorted rotating diode.

Question 5

Overhead - APU OVER SPEED

Answer 5

If overspeed occurs (106%)

Or if overspeed protection feature has failed a self-test during normal APU shutdown.

Question 6

When will the APU Auto shut down?

Answer 6

(All associated amber lights)

Low oil press

Overspeed

Fault

Question 7

When are the APU lights deactivated?

Answer 7

When the switch position is OFF

Unless: A light was on before APU shutdown