Overheat / Fire Protection Panel
OVERHEAT/FIRE Test

The overheat and fire detection loops on both engines, the
APU, and the fire detector in the wheel well are tested by
pushing and holding the FAULT/INOP and OVHT/FIRE TEST
switch in the OVHT/FIRE position.
Only if AC power
is available
during the test.

  • The fire warning bell sounds.
  • Both master FIRE WARN lights illuminate.
  • Both MASTER CAUTION lights illuminate.
  • The OVHT/DET system annunciator light illuminates.
  • Both engine fire warning switches illuminate.
  • The APU fire warning switch illuminates.
  • Both ENG OVERHEAT lights illuminate.
  • The WHEEL WELL fire warning light (illuminates only
    if AC power is available.)
The APU Fire Warning light and Warning Horn in the wheel
well are activated on the ground.
The flight deck indications for the OVHT/FIRE test are: