What happened
On the evening of 24 November 1997, a BAe 146-200, registration EI-COF, was operating a scheduled public transport flight from Dublin to London City Airport. During the takeoff phase and the subsequent initial climb, the flight crew and cabin crew detected a potent odor of fumes within the cabin. This odor intensified as the aircraft continued its flight.
As the flight progressed, the crew members began to suffer physical symptoms, including eye and nasal irritation, throat dryness, headaches, and respiratory discomfort. The cabin crew reported more severe symptoms than the flight deck crew, though the pilots also experienced bouts of dizziness. Despite attempts to mitigate the issue by switching to alternate pack operation, the source of the fumes could not be identified or neutralized.
Upon reaching flight level 210, the crew declared an emergency near the Wallasey VOR. The situation was complicated by the fact that the crew had to don oxygen masks, which made communication with Air Traffic Control extremely difficult. The aircraft subsequently diverted to Manchester Airport, where it landed safely. Notably, the 48 persons on board (5 crew and 4/3 passengers) sustained no injuries, and the passengers did not report any air quality concerns.
The investigation
The investigation focused on identifying the origin of the airborne contaminants within the aircraft's environmental control system. Following the incident, the operator conducted extensive engine ground running procedures to replicate the fault.
Findings
The investigation established that the presence of smoke and fumes in the cabin was caused by oil leaking from the No. 1 bearing seal of the No. 3 engine into the aircraft's bleed air system.