Smoke in the cabin and in the cockpit was generated by pyrolysis of oil at the level of the APU in the ventilation system. The presence of oil was due to a leak in a seal caused by failure of an APU ball race.
To read the full Accident report click here and here.
About the author
John Hoyte is a medically retired BAe146 Training Captain. He is Chairman of 'Aerotoxic Association' which he founded in 2007.