The fire extinguishing system is only available to the engine compartment and utilises a single shot compressed gas canister that is located at the rear of each main landing gear wheel well. When an engine compartment overheat condition is encountered the associated fire warning light will illuminate on the annunciator panel.
|Single shot fire extinguisher bottle located in MLG wheel well.
||Engine compartment fire lights will illuminate when excessive engine compartment temperatures are sensed.
To activate the engine compartment fire extinguishing system the pilot will press the F/W SHUTOFF PUSH buttons which will:
- Close the bleed air shutoff valve,
- Close the fuel firewall shutoff valve,
- Disable the generator, and
- Arm the single shot fire bottle.
Pressing the L/R BOT ARMED PUSH button will then fire the extinguishant into the engine compartment to put out a fire if present.
When engine compartment temperatures return to normal the fire lights will extinguish. If a left or right WING O’HEAT light illuminates temperatures in the wing leading edge have become excessive causing the bleed air shutoff valve to automatically close. The pilot should then monitor the light to ensure that it extinguishes within two minutes.
If a WING O'HEAT light illuminates in flight the pilot need only observe that it extinguishes within two mins
If this WING O'HEAT light does not extinguish within two minutes, ensure that the Wing Overheat checklist is followed in section 3 of the flight manual. The fire protection system is tested before flight by pressing the PRESS TO TEST button located between the F/W SHUTOFF PUSH buttons on the annunciator panel.
|Test the system by pressing the PRESS TO TEST switch
The fire extinguisher bottles are also checked during the preflight inspection by observing the bottle pressure. This fire bottle pressure will change with changes in ambient temperature. The lower scale on the guage indicates the current ambient temperature if the bottle has been correctly serviced and is operational.
Lower portion of guage should read current ambient temp if the bottle serviceable
The correct bottle pressure to temperature scale is shown at table 4-3 in the aircraft flight manual.