11.8 Fire Systems Flashcards
What are the two parts of fire protection?
. Fire detection system
. Fire extinguishing system
Where must fire detection systems always operate?
. Engines and APU
What does a spot sensor use for its switch for fire detection?
Bi - metallic switch
What are the two different continuous loop fire detection sensors?
. Semi conductor loop
. Pneumatic pressure loop
What are the 4 manufacture names for semi conductor loops?
. Kiddle
. Graviner
. Edison
. Fenway
How does a pneumatic pressure loop work?
. Sealed tube of gas
. Pressure of gas increases at high temps
. Gas operates a pressure switch at high pressure levels
What are the two names for pneumatic pressure loop?
. Systron
. Donner
What are the two different types of smoke detectors?
. Optical type
. Ionisation type
Where are smoke detectors used?
. Cargo compartments
. Toliets
. Avionics compartments
For a fire warning what would illuminate?
On overhead panel a red fire warning - local warning
How is the centralised warning cancelled?
By pressing the master warning light when pilot has identified the warning
What two functions does the fire detection system have?
. Receive electrical signals from sensors
. Test functions
What system is a fault detection system?
Loop system
What system prevent a false fire warning because of faliure?
Dual loop system
What are the two types of continuous loops on engines?
. Semi conductor
. Pneumatic pressure valve
What colour is the local fire detection warning?
Red light
What are the two features of an APU fire detection system?
. Ground warning in nose/ main wheel and red light flashes/ warning horn sounds
. APU auto shutdown and auto extinguished
Where is the wheel well fire detection system installed?
In wheel wells which are braked
Where is the wheel wheel fire detection system only required?
Only in an aircraft that has no individual brake temp indication/ warning system
What are the two types of sensors used for pneumatic duct leaks?
. Spot sensors
. Semi conductor continuous loop
Where does the local warning for pneumatic duct leak appear?
On pneumatic or air conditioning panel
Explain class A cargo smoke detection system
. NO fire detection or extinguish because flight deck can see that area
( baggage compartment/ wardrobe)
Explain class B cargo smoke detection system
. Fire detection necessary as ventilatied
. No extinguish as can manually fight
( lower or upper deck that is accessible during flight)
Explain class C cargo smoke detection system
. Fire detection necessary
. Extinguish system necessary
( lower and upper deck that is NOT accessible during flight)
Explain class D cargo smoke detection system
Until year 2003 fire detection and extinguish weren’t needed
Now both are needed - same as class C
Explain class E cargo smoke detection system
.fire detection
No extinguish
( access is possible during flight)
What is required for a lavatory?
Smoke detection system
How many smoke detectors does the avionics smoke detection system have?
1 smoke detector
What is a semiconductor loop made of?
Stainless steel
What are the 3 manufacturers of a single wire semiconductor?
. Fenewal
. Graviner
. Edison
Ahi is the manufacture of a semi conductor loop with two internal wire?
Kidde
What do the semi conductor resistors work on?
Negative temperature coefficient
When there is a fire the ohums decreases to what for an alarm to be triggered?
Below 500 ohums
What loop circuit does a fire detection system follow to prevent miss detection?
Closed loop
If only 1 loop reports, what will the pilot get?
Loop fault message
What is max and min bend radius if semi conductor loop?
Max = 3.2mm
Min = 25.4mm
What are the 2 different smoke detector types?
. Optical
. Ionisation
When would an optical type detector set off the alarm?
When smoke in detector, the light is reflected and lights up the photo resistor causing a decrease is in resistance which sets off an alarm
How does the ionisation type smoke detector detect smoke?
By analysing the composition of air because of different mass of molecules
IAW ionisation type smoke detector what is heavier, clean air or smoke air?
Smoke air is heavier
What smoke detector uses a radiation source?
Ionisation type
Why should you never open ionisation smoke detector?
Because has radiation inside so can cause damage
What are the advatanges of halon?
. Only small amount needed as causes a chemical reaction
. Not chemicaly conductive
. Does not reduce visibility
What three fires can halon be used in?
A,B,C
What must you do to check portable fire extinguisher?
. check overhaul date
. Check not used - pressure gauge in green band and saftey pin in
What is halon 1301 pressurised by and too?
Nitrogen and 600 psi
What is the life of a discharge cartridge?
10 year
How must you handle the discharge cartridge?
With special care
What prevents over pressure of fire extinguisher?
Frangible disc breaks when the pressure inside bottle reaches 1700psi
What colour disc will be missing in fuselage if thermal fuse is used?
Red disc
What colour disc is pushed out if extinguisher is discharged via spray nozzles?
Yellow disc
What is unique about a hot battery bus?
It is always powered by batteries
What must you do before maintaining the firing circuit?
Pull the cbs of firing circuit
What would be the result if squib circuit is broken?
No result of squib test
When pushing fire button or pull T handle what happens?
Extinguisher firing circuit is armed
When pushing fire button or pull T handle what happens?
Extinguisher firing circuit is armed
is number 1 bottle in engine is discharged what colour does it show when it’s empty?
Amber
If fire is still going after 30s what must you go?
Discharge second bottle
What prevents the refilling of an empty first bottle
Check valve
What system do engine extinguishers work on?
2 shot
What fire extinguisher do APU work on?
1 shot system
What is different for APU on ground?
Auto shut off when fire warning on ground
And after 3s after the extinguisher is fired off
During an APU fire test what happens?
Does not activate auto shut down or auto extinguishing
In a cargo compartment fire, when is second bottle fired?
After time delay of several minutes
Is the lavatory system manual or auto?
Automatic
What temp does the fusible end cap melt on lavatory system?
80 degrees C
What does it mean when you see a black temp patch?
Bottle is discharged and needs to be removed for weight check