A captain was forced to bring down a plane carrying 75 passengers after "oily petrol" smells made him and his co-pilot feel sick, a report has found.
British European has since been taken over by Flybe
The pilot had difficulty in judging height during the ensuing approach and landing to Birmingham airport in 2000.
He did manage to bring down the British European plane safely, despite feeling "progressively worse".
The report found the co-pilot felt so "dreadful" he needed oxygen and could take no further part in the flight.
An Air Accidents Investigation Branch (AAIB) investigation revealed there had been an engine turbine oil leak from the generator cooling fan seal of the BAe 146 plane's auxiliary power unit.
This led to fumes entering the cabin and cockpit air supply of the plane, which was flying to Birmingham from Paris on the afternoon of 5 November 2000.
Similar incidents involving Boeing 737, Boeing 757 and Fokker 100 aircraft were reported during the investigation, although flight crews were not so badly affected.
Friday's AAIB report said there was circumstantial evidence to suggest the BAe 146 crew were affected by contamination of the air supply resulting from the oil leak.
The report added that tests indicated the crew, and the crews involved in the similar incidents, "may have been exposed to turbine engine oil-derived fumes" but which had had "an irritant, rather than a toxic effect".
The report said the AAIB had issued five safety recommendations in May 2001 in an effort to ensure there was no repeat of the incidents.
The AAIB said the incident indicated that the "irritant of some kind" to which crews could have been exposed "can cause degradation in decision-making and the reasoning ability of flight crews".
British European became low-cost carrier Flybe in July 2002.
A Flybe spokesman said none of the passengers in the November 2000 incident had been affected by the oil leak.