During descent into Cairns, the pilot of the Embraer EMB-110 observed the right engine fire warning annunciator illuminate. The pilot then conducted the quick reference handbook `fire during flight phase' checks, which included shutting down the right engine. During these checks the fire warning annunciator extinguished, and as there was no visual indication of fire or smoke, the pilot elected not to discharge the engine fire bottle. The quick reference handbook allows for an 8-second wait after the engine is shut down. If the fire warning persists then the fire extinguisher should be discharged. The pilot advised Air Traffic Control and the aircraft passengers of the engine shutdown. An uneventful single engine approach and landing was successfully completed.
The engine fire detection system consists of two independent circuits for each engine. The sensors are located in the hot section, accessories section and the generator cooling air discharge, and are connected to a control box. When a fire or overheat condition is detected a fire warning light will illuminate in the T handle for the affected engine, the master caution light will illuminate and the fire horn will sound.
Investigation by the operator's maintenance organisation found that three fire detector sensors had failed, resulting in a false fire warning. The failed sensors were found to contain moisture. The operator indicated that the aircraft had operated in rain shortly before the incident flight.
The maintenance organisation has indicated that it will ensure that the sealant on the fire detection sensors is adequate to seal against moisture ingestion.
|Date:||19 April 2000||Investigation status:||Completed|
|Time:||1235 hours EST|
|Location:||52 km W Cairns, Aero.|
|Release date:||30 April 2001|
|Report status:||Final||Occurrence category:||Incident|
|Highest injury level:||None|
|Aircraft manufacturer||Embraer-Empresa Brasileira De Aeronautica|
|Type of operation||Air Transport Low Capacity|
|Damage to aircraft||Nil|
|Departure point||Normanton, QLD|
|Departure time||1118 hours EST|
|Role||Class of licence||Hours on type||Hours total|