15.20 Fire Protection Systems Flashcards
(41 cards)
What is a fire zone
Area of an aircraft that requires fire detection and/or extinguishing equipment.
What else is needed in a fire zone
High degree of fire protection
What must multi engine aircraft have
Engine fire protection system
What are the two types of turbine failure
-Thermodynamic
-Mechanical
What is thermodynamic turbine failure
Turbine blades can melt due to thermodynamic air upset. This causes sudden loss of thrust
What can cause overheating and blade melting
Rapid ice formation on inlet screen or inlet guide vanes
What is mechanical turbine failure
Era Fractured or thrown blades, can puncture tail cone causing overheating or fires
Why is penetration of the turbine case very bad
Can penetrate lines carrying fluids such as fuel
What is a complete fire detection system
Has extinguishing and detecting capabilities
How are fires detected on aircraft
-Overheat detectors
-Rate of temp rise detectors
-Flame detectors
What should a fire detector system be
-No false warnings
-Rapid indication of fire and reignition
-Continuous indication for time of fire
-Resistant of heat and damage
What are the two most common engine fire detectors
-Spot detectors
-Continuous loop systems
How does a spot detector work
Uses individual sensors to monitor fire zone eg. Thermal switch, thermocouple and pneumatic
How do continuous loop systems detectors work
Provide complete fire coverage use continuous thermal sensing elements for power plant protection
Example of continuous loop detectors
Fenwal
Kidde
How do thermal switches work
Heat sensitive unit will complete a circuit if it’s too hot and make a fire light light up in the cockpit
How are thermal switches connected
In parallel
How does a thermocouple fire detector work
Detects rate of temperature rise, only warns at fast temp rate increase
What does a thermocouple use to work out rate of temp increase
Has two junctions if there is a fast temperature increase a voltage is produced meaning there is a fire
How do optical fire detectors work
Use IR or UV light and detect hydrocarbon in the air
What aircraft use infrared detectors
Light turboprop aircraft and helicopters
How do pneumatic thermal fire detection work
Element is helium filled tube which expands as it is heated. Only takes an average of an area
Two types of detection in pneumatic detection
Average (uses helium) 93-371°C
Discrete (releases hydrogen when temp is 1100°C for 5 seconds)
What is the 3 names of the manufacturers making discrete pneumatic sensing
-Lindberg
-Systron-Donner
-Meggitt
