APU Fire Panel

Question 1

What controls the APU automatic functions?

Answer 1

The ECB (Electronic Control Box)

Question 2

What fire detection and suppression does the APU have?

Answer 2

Detection: There are 2 Gas filled loops

Suppression: 1 Halon Bottle

Question 3

When will a APU Fire Warning be issued?

Answer 3

• Both Loops detect a fire.
• One loop detects a fire and the other loop is inoperative.
• Both loops break within 5 seconds of each other.

Question 4

If the APU PB is pushed, what happens?

Answer 4

(Walk the panel)
CRC is silenced.
The APU shuts down.
Arms the Squib.
APU fuel pump shuts off (FWD+AFT).
LP Fuel valve closes.
The APU Generator Deactivates.
The APU bleed valve and crossbreed close.

Question 5

If the APU fire test button is pushed, what happens?

Answer 5

2 Master warning lights illuminates (Red)
APU fire PB light illuminates (Red)
APU Fire Warning message (Red)
Agent Squib light illuminates (White)
Discharge PB illuminates (Amber)
CDC

5 Lights a Message and a CRC. (3 Red lights, 1 Red APU Fire Warning message, 1 Amber light, 1 White light)