Fire Extinguishing Systems

Fire Detection System Components

Made up of Loop A and Loop B Fire Detection Elements, a Fire Detection Elements, a Fire Detection Control Unit, and Fire Warning Lights

Fire Detection Element

• Provide the FIRE Warning when an overheat condition exists

• Each is made up of a gas filled tube attached to a Responder Unit

Fire Detection Element: Responder Unit

Contains an alarm switch and an integrity switch

Fire Detection Control Unit

Contains the necessary relays and diodes required for system activation

FIRE Warning Lights

Each is made up of four sections with a light in each section, each light corresponds to the area of the affected bay

Left engine Fire Warning Light

Located on the LH Advisory and Threat Warning Indicator Panel

APU and Right engine FIRE Warning Lights

Located on the RH Advisory and Threat Warning Indicator Panel

Intercommunication and Audio System

Transmits a voice alert message for a FIRE WARNING CAUTION condition existing in the Fire Detection System requiring immediate attention

The closed switch completes a circuit for _____ vdc to the related FIRE Warning Light. 

24/28

Fire Extinguishing Tank

Cylindrical container mounted vertically between the engines

Filled with non-corrosive inert gas containing _____ pounds of bromotrifluoromethane 

5.5

Supercharged with gaseous nitrogen, ___ to ___ psig, at ____

600, 625, 72°F 

Discharge Outlets

• 3 Discharge outlets at the bottom of the tank

• Each outlet has a distribution line and nozzle for each bay

READY/DISCH Switch

• Illuminate yellow, indicating Fire Extinguishing System is armed and ready for discharge

• Pressing the switch discharges the Fire Extinguishing and light will illuminate green

APU Fire Extinguishing Ground Operation

Automatic APU Fire Extinguishing System will shut down the APU and discharge the fire extinguisher when a fire is detected

APU Fire Extinguishing Manual Operation

The operator has the option to manually activate the Fire Extinguishing System, which shuts down the APU and discharges the fire extinguisher

Engine Fire Extinguishing for engines

Operation is identical for both engines

Maintenance of Fire Detection/Extinguishing System

Visual Inspection, System Testing, Removal and Replacement of Components