Module 15.20 Fire protection systems Flashcards
Where would fire detection take place?
Fire zone
What is in a fire zone?
Detection and/or extinguishing
What are the two major types of turbine failure?
- Thermodynamic
- Mechanical
Rapid build up go ice on inlet screens or IGV’s can result in what?
Severe overheating
Generally most thermodynamic failures are cause by what?
- Ice
- Excess air bleed or leakage
- Faulty controls that allow compressor stall or excess fuel
Mechanical failures, such as fractured or thrown blades, can puncture what?
The tail cone
What does a complete fire protection system include?
Fire detection and extinguishing
How are fires detected?
By using one more of the following detectors:
- Overheat
- Rate of rise
- Flame
What are the most common types of detectors?
Spot detectors and continuous loop
What detection systems are used on older aircraft?
- Thermal switch
- Thermocouple
How are thermal switches connected relative to each other?
In parallel
What are optical detectors sometimes referred to as?
Flame detectors
What do the thermocouple control?
Operation of the relay
What do the relays control?
The warning lights
What are the two types of optical sensors available?
- Infrared
- Ultraviolet
When would infrared detectors be used?
Light turboprop and helicopter engines
What does the integrity switch do?
Triggers fault alarm in loss of pressure as in the case of a leak
The pneumatic detector has what two sensing functions?
- Average
- Discrete
Average temp sensing is within what range?
93℃ to 371℃
Both the average and discrete functions are what?
Reversible
What are the two types of continuous loop detector systems?
- Fenwal
- Kidde
The fenwal system automatically returns to what after extinguishing?
Standby alert
How do you know there is a fire in continuous loop system?
Alarm conditions on both loops
How many shots does the APU often have?
One shot
What does a High Rate Discharge system use to deliver?
Open end tube
Why is Halon 1301 used
Effective, low toxicity and non corrosive
Engine fire protection systems are designed to? (Gases)
Dilute the atmosphere with an inert agent
How are fire bottles pressurised? What fluid?
Nitrogen
When can cylindrical shaped fire bottles be used?
When space is limited
What is installed in the outlet of the discharge valve assembly?
A cartridge (squib) and frangible disc-type valve
How is visual fire bottle pressure given?
Via a vibration resistant helical bourdon type indicator
When are two way check valves required in a fire extinguishing systems?
Two shot system, to prevent agent backing up in the reserve container
What does the red disc indicate?
Thermal discharge
What does the yellow disc indicate?
Pilots have discharged it
What fire warning systems are installed?
Visible and audible warning systems are installed in the flight deck to alert the flight crew
What happens if both junctions of a thermocouple are heated at the same rate?
No voltage is produced
What does the fire detection card monitor the loops for?
- Fire
- Overheat
- Faults
