15.20 Fire Protection Systems Flashcards
What are the 2 major types of turbine failures?
Thermodynamic.
Mechanical.
What is a fire zone?
A zone designated by the manufacturer to require fire detection and/or fire extinguishing equipment.
What does a thermodynamic turbine failure cause?
Reduces the proportion of air used to cool down combustion temperature.
A thermodynamic turbine failure can be caused by ice, what effect could this have?
Severe overheating.
What is a mechanical turbine failure?
A fractured or thrown blade.
Due to a mechanical failure, what can cause a burn through of the tail cone?
High flow of fuel through an improperly adjusted fuel nozzel.
What are the 3 fire detectors used?
Overheat.
Rate of temperature rise.
Flame.
Do engines have a common fire detection system?
No, separate for each engine.
What are the 2 most common type of fire detection systems?
Spot detectors.
Continuous loop system.
How does a spot detector system work?
Uses individual sensors to monitor a fire zone.
What does a continuous loop detection system use?
Uses several loop type sensors.
Where are thermal switch systems used?
On older aircraft.
How are thermal switches connected in a circuit?
In parallel with each other.
In series with indicator lights.
How does a thermal switch system work?
Heat sensitive units complete a circuit at a set temp.
What does a thermocouples system depend on?
Depends on rate of temperature rise.
Will a thermocouples system give a warning if an engine slowly overheats?
No
How does a thermocouples system work?
Produces a voltage because of a temperature difference between a hot and reference junction.
What controls the warning lights in a thermocouple system?
Relays.
What are the 2 types of optical fire detectors?
Infrared and ultraviolet.
Where are infrared optical fire detection systems used?
On light turboprop aircraft and helicopters.
What does a pneumatic thermal fire detection system consist of?
A closed helium filled tube
What does the pneumatic fire detection system respond to?
An overall average temp threshold.
And a localised discrete temp increase.
What is the purpose of the integrity pressure switch in a pneumatic fire detection system?
Triggers a fault alarm in case of a leak.
What is the average temp sensing range?
200 to 700 F
93 to 271 C
What is the discrete temp sensing range?
1100 for 5s
Are the average and discrete temp sensing systems reversible?
Yes
What are the pneumatic systems called?
Lingberg,
Systron donner,
Meggit
What are the continuous loop systems called?
Kiddie and Fenwall
How is the fenwall system made?
An inconel tube packed with a eutectic salt and a nickel centre conductor.
How do fenwall and kidde systems respond to a fire?
Resistance drops.
How does a Kidde system differ from fenwall?
Additional conductor connected to the ground.
How is a fire system test actuated?
By a test switch in the flight deck.
How many discharges does an engine fire detection system have?
2
What are fixed fire extinguishing agents designed to do?
Dilute the atmosphere with an inert agent.
What fire extinguishing agent is used?
Halon 1301.
What are container fire bottles pressurised with?
Nitrogen.
What shape are container fire bottles usually?
Spherical.
What is intalled in a discharge valve?
Cartridge squib.
Frangible disc.
In a standard discharge valve, What ruptures a segmented closure disc?
A slug driven by explosive energy.
How is pressure of fire bottles indicated?
Visually, typically a Bourden type indicator.
How is a thermal bottle discharge indicated?
Red discharge indicator.
How is a normal bottle discharge indicated?
Yellow discharge indicator.
