What happened
On 17 November 2005, a Darwin Airline SAAB 2000, registration HB-IZZ, was performing a scheduled departure from Lugano Airport to Geneva. During the takeoff acceleration phase, at a speed of approximately 60 knots, the flight crew received an aural warning and a visual alert indicating smoke in the forward lavatory.
In response to the warning, the commander immediately aborted the takeoff. The aircraft came to a halt on runway 01 after traveling roughly 480 meters. Upon contacting the cabin crew to verify the situation, the commander was informed that smoke was indeed present in the cabin. Consequently, the commander ordered an emergency evacuation. Passengers exited the aircraft via the front and rear doors, jumping from heights of up to 1.78 meters. One passenger sustained a slight injury to the foot during the process.
The investigation
The investigation focused on the source of the smoke and the subsequent emergency response. Technical examinations of the aircraft's propulsion system revealed that a defective seal on the adjusting piston of the propeller allowed gearbox oil to leak into the propeller housing. This oil was subsequently drawn into the engine air inlet, entering the bleed air system and passing through the air-conditioning pack into the passenger cabin. This process created a mist that the sensors identified as smoke.
The investigation also reviewed the actions of the airport fire brigade. It was noted that at the time of the alarm, the fire brigade personnel were engaged in other airport duties and were not stationed at the fire station. Furthermore, the fire brigade commander initially misidentified the genuine emergency as a training exercise, delaying the realization of the actual incident for several minutes.
Findings
- The primary cause of the smoke warning was contaminated air from the air-conditioning system resulting from oil leakage.
- A defective seal on the propeller's adjusting piston allowed gearbox oil to reach the exterior of the housing.
- The crew's decision to evacuate was made seven seconds after the aircraft stopped.
- The airline's emergency evacuation procedures and checklists contained discrepancies compared to the manufacturer's official documentation.
- The airport fire brigade commander incorrectly reported the alarm as a test exercise to other agencies for approximately 20 minutes after the alarm was raised.