Engine / APU Fire Push Switches

Question 1

What happens when you push the L/R engine fire switches?

7

Answer 1

1. Squib is Armed
2. Both EXT 1 and EXT 2 switches illuminate “ARMED”
3. FUEL SHUTOFF Valve CLOSED
4. BLEED AIR SHUTOFF Valve CLOSED
5. HYDRAULIC SHUTOFF Valve CLOSED
6. Generator Selected OFFLINE
7. FADEC Commands engine shutdown

Question 2

Which EXT is can be used for the APU?

Answer 2

EXT 2, so use EXT 1 for engine fires first.

Question 3

What happens when you press the APU Fire Switch?

5

Answer 3

1. EXT 2 switch illuminates “ARMED”
2. APU FUEL SHUTOFF valve closes.
3. APU’s ECU closes the FUEL METERING valve.
4. APU BLEED AIR SHUTOFF VALVE Closes.
5. APU GENERATOR is selected OFFLINE.