Fire Protection

Question 1

How is fire detected in the engines and APU?

Answer 1

APU and engines each have 2 fire loops that run in parallel. Heat detecting elements in each loop detect high temperature. When both loops in the engine detect high temp, the FDU will signal a fire warning.

A warning also sounds if they both break within 5s of each other due to flames

Question 2

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

Answer 2

Avionics bay: smoke detector in extract system detects smoke for 5s

Cargo bay: 4 smoke detectors in rear hold (2 in each) and 2 in front hold. Work on a loop system where both need to detect smoke

Question 3

Where do the fire loops run through the engines?

Answer 3

Nacelle
Fan
Core
Pylon

Question 4

When APU fire is detected on ground what happens?

Answer 4

APU auto shuts down and fire bottle is discharged

Question 5

What fire extinguishers are in the cargo holds?

Answer 5

One bottle for all 3 holds
Each hold connected by pipes to a nozzle
Takes 1 minute for bottle to discharge

Question 6

What happens when fire push button pressed? (8 items)

Answer 6

Closes LP fuel valve
Closes hydraulic shut off valve
Closes engine bleed
Closes pack control valve
Arms squibs
Cuts FADEC power
Deactivates IDG
Silenced aural warning

Question 7

What happens when APU fire pb pressed? (6 items)

Answer 7

APU shut down
APU bleed valve and crossbleed shut
APU fuel pump deactivated
LP fuel valve closed
Squibs are armed
Aural warnings silenced