Systems - Fire Protection

Question 1

How does the fire detection system detect heat?

Answer 1

uses a fire loop

Question 2

How many fire loops do we have?

Answer 2

• 2 per engine - one wraps around each engine and one wraps around the pylon.
• and and 1 for the APU.

Question 3

How do the fire loops work?

Answer 3

They run gases (hydrogen and helium) through a very small guage wire (smaller in diameter than a coat hangar) on a loop. When the loop is heated the gas will expand and complete a circuit which will send an electrical signal to the fire warning lights.

Question 4

What happens if there is a leak in a loop? How might a leak be caused?

Answer 4

It will not detect heat anymore and you will get an EICAS message. It might be caused by a fire causing the loop wire to melt and gases escape. If you suspect this you should blow both bottles.

Question 5

How is the fire detection system powered?

Answer 5

Electrically off the essential BUS.

Question 6

What is the intent of the system when the Fire Handle is pulled?

Answer 6

Remove:

1) Things that can feed a fire (Hyd Oil or Fuel)
2) Things that can cause a fire (Eng Bleed)

Question 7

Once you pull a fire handle, what should you do before you blow a bottle

Answer 7

Wait 30 secs to see if fire goes out.

Question 8

When you blow a bottle, where is the halon discharge sent?

Answer 8

Around the outside of the engine.

Question 9

How many total fire bottles do we have?

Answer 9

3 total.

2 for the engines

1 for the APU

Question 10

Which BUS are the engine Fire Bottles on?

Answer 10

HOT BUS.

Question 11

Which BUS is the APU fire bottle on?

Answer 11

Essential BUS.

Question 12

How do you conduct a Fire Test

Answer 12

Fire Test Button - Press and Hold

OBSERVE

Fire Bells - Sounding

Master Warning & Caution - Illuminated

Fire Handles - Illuminated

Baggage Fire Extinguisher Button - Illuminated

OBSERVE EICAS MESSAGES

Question 13

What EICAS messages will you get during a Fire Test

Answer 13

1) APU Fire
2) ENG 1(2) Fire
3) Bagg Smoke
4) APU Fire Det Fail
5) ENG 1(2) Fire Det Fail.

Question 14

What happens if you hold the Fire Test button for more than 9 seconds

Answer 14

The APU will not know what is happening and will shut down.

Question 15

What will happen if you hold the Fire Test button for less than 3 seconds? What do you do to remedy the situation?

Answer 15

Bag smoke light may remain illuminated (false light). Wait 6 seconds and do another test to clear it.

Question 16

What happens when you push the APU fire extinguisher button?

Answer 16

1) Shuts off fuel at the wing root
2) Fires the bottle.

Question 17

Where is smoke detection available?

Answer 17

Lavatory and Baggage Compartment.

Question 18

How many smoke detectors are in the baggage compartment and how do they operate?

Answer 18

2 smoke detectors, which upon detecting smoke will:

1) Send a signal to shutoff the fan (seals the compartment)
2) Light the baggage fire extinguisher button
3) Send an EICAS message.

Question 19

How many fire bottles does the baggage compartment have? How do they operate?

Answer 19

2 bottles

High Rate Discharge Bottle - puts the fire out

Meterning Discharge Bottle - meters halon for 50 mins to keep the fire out

Question 20

what happens when you push the bag fire extinguisher button?

Answer 20

1) Sends another signal to shuto off the fan (to make sure compartment is sealed).
2) Fires the bottles in sequence.

Question 21

What should you consider when you push the bag fire extinguisher button to extinguish a baggage fire?

Answer 21

The EICAS warning may not go out because the smoke may not have anywhere to go (sealed environment) and the halon may be mistaken by the same detector as smoke.

Question 22

What should you consider if you get a Bag Smoke Light with No EICAS message? What if you get a Bag Smoke EICAS with or without the Bag Smoke Light?

Answer 22

1) Bag Smoke Light (NO EICAS) = Fan is Inop
2) Bag Smoke EICAS = Baggage compartment on Fire!

Question 23

What is shut off when the Fire Handles are pulled?

Answer 23

1) Fuel Shutoff Valve
2) Engine Bleed Valve
3) LIP Anti-Ice
4) Hyd Shutoff Valve.