Fire Protection

Question 1

What does the fire and smoke protection system include ?

Answer 1

• Fire and overheat detection for the engines and APU
• Smoke detection for the cargo compartments, the lavatories, and the avionics bay
• Fire extinguishing for the cargo compartments, the engines, the APU, and the lavatories.
• Portable fire extinguishers in the cockpit and in the cabin areas.

Question 2

What is the FDU ?

Answer 2

The Fire Detection Unit

Question 3

How many loops do the engines and APU each have ?

Answer 3

2 independant continuous detection loops (A and B) mounted in parallel to the FDU.

Question 4

How many engine fire sensing elements do the engines have ?

Answer 4

3 engine fire sensing elements (in the pylon nacelle, in the engine core, and in the engine fan section)

Question 5

How many engine fire sensing elements does the APU have ?

Answer 5

1 engine fire sensing element (in the APU compartment)

Question 6

What happens when a loop fails (break or loss of electrical supply) ?

Answer 6

It does not affect the warning system and the unaffected loop still protects the aircraft

Question 7

How many fire-extinguishing bottles do the engines have ?

Answer 7

Each engine has 2 fire extinguisher bottles (inside the pylon), with electrically-operated squibs to discharge their agents

Question 8

How many electric supply does the squib have ?

Answer 8

Each squib has a dual electric supply.

Question 9

How many fire-extinguishing bottle does the APU have ?

Answer 9

The APU has 1 fire extinguisher bottle, with two electrically-operated squibs to discharge its agent

Question 10

What happens when an APU fire is detected on the ground ?

Answer 10

When an APU fire is detected on the ground, the APU automatically shuts down, and the extinguisher bottle discharges automatically

Question 11

How does the Fire Detection Logic work ?

Answer 11

The FDUs process all the warnings and cautions originating in the sensing elements
A fire warning occurs, if:

• Both loops A and B send a fire signal, or
• One loop sends a fire signal and the other one is failed, or
• Breaks occur in both loops within 5 s of each other (flame effect), or
• A test is performed on the FIRE panel

Question 12

What happens when the ENG1(2) Fire pb is pushed ?

Answer 12

• Silences the aural fire warning
• Arms the fire extinguisher squibs
• Closes the low-pressure fuel valve
• Closes the hydraulic fire shut off valve
• Closes the engine bleed valve
• Closes the pack flow control valve
• Cuts off the FADEC power supply
• Deactivates the IDG.

Question 13

How many smoke detector are there in the lavatory and where are there located ?

Answer 13

1 smoke detector, in the ceiling, in the extraction outlet duct of the lavatory

Question 14

What happens when smoke is detected in the lavatory ?

Answer 14

It send signals to the SDCU, which sends signals to both the Flight Warning Computer and CIDS

Question 15

Whats is the SDCU ?

Answer 15

Smoke Detection Control Unit

Question 16

What about the wastebin ?

Answer 16

Each lavatory has wastebin extinguisher, which is automatically discharged when temperature exceeds 80°C. Smoke has no effect on the extinguisher. (only temperature threshold must be exceeded).

Question 17

At what temperature the wastebin fire extinguisher is discharged ?

Answer 17

When the temperature reaches 80°C