Fire Detection Prevention

Question 1

What airplane systems have fire detection and protection (extinguishing) capabilities?

Answer 1

Lavatories
APU
Cargo Compartments
Engines

Memory Aid: L.A.C.E (We don’t want the LACE to burn)

Recirc Bay (SMOKE DETECTION ONLY)

Question 2

What items are available to the crew to protect the cockpit and cabin from fire?

Answer 2

Cockpit - 1 hand-held Halon fire extinguisher

Cabin - 3 hand-held Halon fire extinguishers (1 fwd. and 2 aft); one water extinguisher (aft, aircraft right)

Question 3

How are the engines and APU protected from fire?

Answer 3

Engines: 2 Halon fire bottles

APU: 1 Halon fire bottle dedicated to the APU only

Question 4

Can both engine fire bottles be used for one engine if needed?

Answer 4

Yes.

A total of 2 fire extinguisher bottles named A and B are installed in the airplane to serve either or both engines.

Question 5

What is the power source for engine and APU fire detection and protection?

Answer 5

Engine Detection: DC ESS BUS 1 and 2
Engine Protection: HOT BATT BUS 1 and 2

APU Detection DC ESS BUS 1 and 2
APU Protection: DC ESS BUS 2

Question 6

Describe the engine and APU fire detection system

Answer 6

Engine: 8 Pneumatic fire detectors (2 loops) per engine.

APU: 2 Pneumatic fire detectors (2 loops).

Question 7

What happens when an engine fire handle is pulled?

Answer 7

Closes respective engine fuel SOV.

Closes respective engine hydraulic SOV.

Closes respective engine bleed SOV.

Question 8

What is an indication of an APU fire?

Answer 8

4 indications:
Fire Bell
Red stripe in the EMER STOP button
Master WARNING lights illuminate
APU FIRE is displayed on the EICAS

Question 9

Will the APU automatically shut down if a fire is detected?

Answer 9

Only on the ground 10 seconds after the fire condition is present

Question 10

What happens if the APU EMER STOP button is pushed after a fire has been detected?

Answer 10

APU shuts off immediately without a 1-minute cool-down.

APU fuel SOV closes.

APU FIRE EXTG button illuminates (bottle armed)

Question 11

What happens if the APU EMER STOP button is NOT pushed after a fire has been detected?

Answer 11

After one minute the APU FIRE EXTG button illuminates (bottle armed)

Question 12

Will the APU fire extinguisher automatically discharge?

Answer 12

No

Question 13

How many smoke detectors are installed in the cargo compartments?

Answer 13

3 detectors in the FWD compartment.

2 detectors in the AFT compartment.

Question 14

What happens to the forward cargo compartment in the event smoke is detected?

Answer 14

Recirculation fan shuts off.
Ventilation outflow valve closes.
FWD Cargo smoke button is illuminated.

Question 15

Why does the recirculation fan shut off and ventilation outflow valve close in the forward cargo compartment when smoke is detected?

Answer 15

Prevents oxygen from entering the compartment.

Prevents Halon agent from escaping into the aircraft’s cabin.

Question 16

How many extinguishing bottles are installed for the cargo compartments?

Answer 16

2 bottles used for both compartments.

1 high-rate bottle and 1 low-rate bottle.

Both extinguisher bottles are installed in the center avionics bay and used in either forward or aft cargo compartment, not both simultaneously.

Question 17

What is the difference between the high-rate bottle and the low-rate bottle?

Answer 17

High-rate bottle saturates the compartment immediately.

Low-rate bottle maintains saturation over a duration of time.

Question 18

How long will the low-rate bottle remain active in the compartment?

Answer 18

60 minutes

Question 19

Can one bottle be used for the FWD compartment and the other bottle for the AFT compartment?

Answer 19

No. Only one compartment may be selected. (FWD or AFT)

Question 20

What happens when a cargo extinguishing button is pushed if smoke has been detected?

Answer 20

High-rate bottle discharges immediately. Low-rate bottle discharges after one minute if the airplane is in flight.

If airplane is on the ground (weight on wheels) the low-rate bottle will NOT automatically discharge.

Question 21

During flight, can the low-rate bottle be discharged before the minute is up?

Answer 21

Yes, by pushing the respective extinguishing button again.

Question 22

How can the low-rate bottle be discharged if the airplane is on the ground (weight on wheels)?

Answer 22

In case of fire on ground, the low-rate fire extinguishing bottle is not automatically discharged. The flight crew must push the cargo fire extinguishing push button a 2nd time to discharge the low-rate bottle.

Question 23

Can cargo extinguishing be used if no smoke is detected?

Answer 23

Yes. The bottle extinguishing button must be pushed twice, once to arm the bottle and once to discharge the high-rate bottle.

The low-rate bottle automatically discharges after one minute in flight.

Question 24

How are the lavatories protected from fire?

Answer 24

Heat-sensitive extinguishers in both lav waste bins automatically discharge if a predetermined temperature is reached.

Question 25

If an incorrect cargo compartment is armed, how can the panel be reset?

Answer 25

Wait 2 minutes then press the test button.