M15.20 Fire Protection Flashcards
Two major types of turbine failure?
Thermodynamic
Mechanical
What is thermodynamic turbine failure?
Thermodynamics causes an upset to the proportion of air used to cool down combustion temperatures to levels the turbine materials can tolerate.
When the cooling cycle is upset the turbine blades can melt causing sudden loss of thrust
What is an example of how thermodynamic turbine failure can occur?
Rapid build up of ice on inlet screens or inlet guide vanes can result in severe overheating. Causing turbine blades to melt
What are the potential issues due to mechanical turbine failure?
Fractured or thrown blades that can puncture the tail cone causing overheating conditions
A complete fire protection system includes what?
Both fire detection and fire extinguishing
Fires are detected in aircraft by using what detectors?
Overheat detectors
Rate of temperature rise detectors
Flame detectors
Two most common fire detection systems?
Spot detectors
Continuous loop systems
How does a spot type detector work?
Uses individual sensors to monitor a fire zone
E.g a thermal switch, thermocouple, optical fire detection
How do continuous loop systems work?
Installed on transport type aircraft
Provide a more complete fire protection by using several loop type sensors
How does a thermal switch work?
Heat sensitive units
If indicator temp rises above set value in a location, the thermal switch closes completing the light circuit to indicate a fire or overheat condition
How does a thermocouple system work?
Depends on rate of temperature increase - won’t alarm by slight temp increase
A thermocouple system consists of what?
A relay box
Warning lights
Thermocouples
Two types of optical fire detection systems?
Infared and ultraviolet
How does an optical fire detection system work?
Designed to alarm when they detect a presence of radiation emissions from hydrocarbon flames
How does a pneumatic thermal fire detector work?
As the element is heated, the gas pressure inside the tube increases until the alarm threshold is reached and sends an alarm to flight deck
How does average temperature sensing work?
Activated by the expansion of a fixed volume of helium gas inside the detector
How does discrete temperature sensing work?
Using a hydrogen filled core material in a sensor tube.
Hydrogen gas is released from the detector core whenever a small section of the tube is heated to a pre set discrete temp for 5 seconds
This out gassing increases the pressure inside the detector and sounds the alarm
Two types of continuous loop systems?
Fenwal
Kidde
