Fire Protection

Question 1

How is fire detected in engines and APU?

Answer 1

Works on a loop system, 2 loops in parallel with heat sensing elements. ECAM Warning if BOTH loops detect, or ONE detects if other failed, or BOTH loops fail within 5 secs.

Question 2

How is a fire detected in avionics bay and cargo holds?

Answer 2

Avionics: One smoke detector downstream of avionics cooling equipment.
ECAM triggered if smoke detected for more than 5 secs. FAULT lights on BLOWER and EXTRACT pb, and SMOKE on GEN 1 LINE pb.
Smoke configuration is only protection.

Cargo: 2 smoke detectors in FWD hold, 4 in AFT (6 A321) in loop system. Both loops need to detect smoke to trigger ECAM warning.

Question 3

Where do the fire loops run throughout the engine?

Answer 3

Pylon nacelle, engine core, and engine fan section.

Question 4

If APU FDU detects a fire when the a/c is on the ground, what happens?

Answer 4

APU auto shutdown and fire bottle discharged.

Question 5

What fire extinguishers do we have for cargo holds?

Answer 5

One bottle covers all holds, one nozzle per hold bay. Can take up to one minute for bottle to discharge.

Question 6

What happens when a fire pb is pressed?

Answer 6

1. Silences the warning
2. Arms the squibs
3. Closes LP fuel valve
4. Closes the hydraulic fire shut off valve
5. Closes the eng bleed valve
6. Closes the pack flow control valve
7. Cuts of the FADEC power supply
8. Deactivates the IDG

Question 7

What happens if the APU fire pb is pressed?

Answer 7

1. Shuts down the APU
2. Silences the warning
3. Arms the squib
4. Closes the LP fuel valve
5. Shuts off the APU fuel pump
6. Closes APU bleed valve and X bleed valve, and deactivates the APU generator