What happened
On 19 March 2006, an AVRO 146-RJ100, registration HB-IXS, operated by Swiss European Air Lines, was performing a scheduled flight from Paris to Zurich. During the final moments of the approach, the crew initiated a changeover to use bleed air from the auxiliary power unit (APU) to ensure sufficient engine power for a potential go-around.
Seconds before the aircraft touched down on runway 14, the copilot noticed blue-colored smoke appearing on the right side of the cockpit. While the landing itself was uneventable, the smoke density increased as the aircraft taxied. Although the smoke initially appeared to subside, it soon spread to the passenger cabin. The commander subsequently halted the aircraft on taxiway H1 and ordered an immediate evacuation. The 95 passengers and crew were evacuated via emergency slides in less than 90 seconds. No injuries were reported among the passengers or crew.
The investigation
The Aircraft Accident Investigation Bureau (AAIB) examined the flight data and cockpit voice recordings to determine the source of the smoke. The investigation focused on the timing of the APU activation and the air conditioning system's configuration. Investigators also reviewed the maintenance history of the APU and the crew's adherence to evacuation protocols and operational manuals.
Findings
- The smoke was likely introduced into the aircraft through the air conditioning system.
- The APU was started later than prescribed by the airline's operations manual, which requires activation upon receiving clearance to a pressure altitude.
- There was a very short interval—approximately 15 seconds—between switching to APU bleed air and the appearance of smoke in the cockpit.
- The specific APU involved was later linked to a similar smoke incident on a different aircraft (HB-IXO) in June 2006, suggesting the unit was the source of the contamination.
- While the evacuation was highly efficient, the commander's verbal command did not strictly follow the exact wording prescribed in the cabin safety procedures.