The wheel well APU fire warning horn
sounds, (on the ground only), and the
wheel well APU fire warning light flashes.
sounds, (on the ground only), and the
wheel well APU fire warning light flashes.
Wheel Well APU Fire Control
APU Fire Protection
APU fire protection consists of these systems:
APU Fire Detection
A single fire detection loop is installed on the APU. As the temperature of the
detector increases to a predetermined limit, the detector senses a fire condition.
The APU fire warning switch remains illuminated until the temperature of the
detector has decreased below the onset temperature.
The system contains a fault monitoring circuit. If the loop fails, the APU DET
INOP light illuminates indicating the APU fire detection
system is inoperative.
The indications of an APU fire are:
APU fire protection consists of these systems:
- APU fire detection powered by the battery bus.
- APU fire extinguishing powered by the hot battery bus.
APU Fire Detection
A single fire detection loop is installed on the APU. As the temperature of the
detector increases to a predetermined limit, the detector senses a fire condition.
The APU fire warning switch remains illuminated until the temperature of the
detector has decreased below the onset temperature.
The system contains a fault monitoring circuit. If the loop fails, the APU DET
INOP light illuminates indicating the APU fire detection
system is inoperative.
The indications of an APU fire are:
- The fire warning bell sounds.
- Both master FIRE WARN lights illuminate.
- The APU fire warning switch illuminates.
- The APU automatically shuts down.