London Heathrow Airport, London, England, United Kingdom
Los Angeles International Airport, Los Angeles, California, USA
Type of flight:
During takeoff part of the cabin filled with a light white mist and an accompanying ‘oily’ smell. The flight crew declared a PAN, dumped fuel and then made an uneventful return to the airport. The mist was probably caused by the ingestion of oil or other contaminant into the APU inlet which passed into the bleed air duct and cabin air conditioning system. The fluid contaminant probably emanated from a drain hole forward of the APU inlet. This drain hole was found blocked some time after the incident and, once cleared, it released almost a litre of an oil-water mixture.