Systems - Fire Protection Flashcards
How does the fire detection system detect heat?
uses a fire loop
How many fire loops do we have?
- 2 per engine - one wraps around each engine and one wraps around the pylon.
- and and 1 for the APU.
How do the fire loops work?
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.
What happens if there is a leak in a loop? How might a leak be caused?
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.
How is the fire detection system powered?
Electrically off the essential BUS.
What is the intent of the system when the Fire Handle is pulled?
Remove:
1) Things that can feed a fire (Hyd Oil or Fuel)
2) Things that can cause a fire (Eng Bleed)
Once you pull a fire handle, what should you do before you blow a bottle
Wait 30 secs to see if fire goes out.
When you blow a bottle, where is the halon discharge sent?
Around the outside of the engine.
How many total fire bottles do we have?
3 total.
2 for the engines
1 for the APU
Which BUS are the engine Fire Bottles on?
HOT BUS.
Which BUS is the APU fire bottle on?
Essential BUS.
How do you conduct a Fire Test
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
What EICAS messages will you get during a Fire Test
1) APU Fire
2) ENG 1(2) Fire
3) Bagg Smoke
4) APU Fire Det Fail
5) ENG 1(2) Fire Det Fail.
What happens if you hold the Fire Test button for more than 9 seconds
The APU will not know what is happening and will shut down.
What will happen if you hold the Fire Test button for less than 3 seconds? What do you do to remedy the situation?
Bag smoke light may remain illuminated (false light). Wait 6 seconds and do another test to clear it.
What happens when you push the APU fire extinguisher button?
1) Shuts off fuel at the wing root
2) Fires the bottle.
Where is smoke detection available?
Lavatory and Baggage Compartment.
How many smoke detectors are in the baggage compartment and how do they operate?
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.
How many fire bottles does the baggage compartment have? How do they operate?
2 bottles
High Rate Discharge Bottle - puts the fire out
Meterning Discharge Bottle - meters halon for 50 mins to keep the fire out
what happens when you push the bag fire extinguisher button?
1) Sends another signal to shuto off the fan (to make sure compartment is sealed).
2) Fires the bottles in sequence.
What should you consider when you push the bag fire extinguisher button to extinguish a baggage fire?
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.
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?
1) Bag Smoke Light (NO EICAS) = Fan is Inop
2) Bag Smoke EICAS = Baggage compartment on Fire!
What is shut off when the Fire Handles are pulled?
1) Fuel Shutoff Valve
2) Engine Bleed Valve
3) LIP Anti-Ice
4) Hyd Shutoff Valve.
