Incident Overview
On 23 November 2007, an Airbus A319 (registration CS-TTK) operating a scheduled passenger flight from London Heathrow to Lisbon experienced an in-flight smoke event. The aircraft, manufactured in 1999 and powered by two CFM56-5B5P turbofan engines, had 6 crew and 91 passengers on board. No injuries or damage were reported.
Sequence of Events
Shortly after departure from Runway 09L at Heathrow, the chief purser reported to the flight crew that dense smoke had appeared in the rear passenger cabin, accompanied by a smell of burnt plastic. No caution or warning lights illuminated on the flight deck. The crew radioed air traffic control (ATC) to declare a MAYDAY, stating they had smoke in the cabin and requested a return to land. ATC instructed the crew to squawk 7700 and vectored them for an approach to Runway 09R. During the approach, the smoke cleared, and the aircraft made a normal landing, taxied, and shut down normally. Passengers disembarked without incident, and the fire service inspected the aircraft but found no evidence of burning.
Investigation
The aircraft operator conducted an investigation to determine the smoke source. Inspections were carried out on the entire cabin, galleys, ovens, toilets, cabin lights, engines, auxiliary power unit (APU), and cargo bays. No evidence of burning or anomalies was found. Despite these efforts, the origin of the smoke could not be identified. The operator indicated that further attempts to determine the cause were deemed unlikely to succeed.