A RESEARCHER at a Scots university has lifted the lid on “fume events” on commercial aircraft, where oil leaks into the engine compressor, the source of cabin breathing air in the vast majority of modern aircraft.

Dr Susan Michaelis – a former airline pilot in Australia – started as a visiting researcher at Stirling University’s Occupational and Environmental Health Research Group after she was medically retired following exposure to the toxic air.

She said the air passengers and crew breathe on most jet airliners, except the B787 Dreamliner, is what is called “bleed air”, which is taken from the flow entering the engine and piped into the cabin unfiltered. It can then lead to a condition known as aerotoxic syndrome.

Michaelis said her research has shown it can become contaminated by engine oil containing chemicals called organophosphates, which leaks at low levels in all flights when pressurised air from the engine is used to seal the engine oil system and bearing chambers.

Her research is backed by a documentary, Everybody Flies, by former British Airways captain Tristan Loraine, to be screened at Glasgow’s Everyman Cinema on March 9. This will be followed by a Q&A session with Loraine.

Michaelis told The National her problems started when she was flying in Australia: “I was flying from the mid-1980s  and once on the on the BAe 146 out of Canberra  I immediately smelled oil.

“It was so regular on changing power and air supply and they told me that I’d get better as soon as I was out of that environment.

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“"I was the first officer so I knew what I was doing and I would get sick short-term, then go out into the fresh air or settle down in the cruise and I was fine.

“After two-and-a-half-years I could no longer do the job because it was getting worse and worse ... not realising I wouldn’t get better after that day, 23 years ago.”

She added: “I wanted answers because I’d worked hard for my flying licence and so on and I needed answers.”

Her search took Michaelis, who has 5000 hours of flying time under her belt, to the University of New South Wales and then to Stirling.

Along the way she has qualified as an air accident investigator, published many papers on fume events, as well as giving presentations around the world.

Michaelis said that based on research, in terms of clean cabin air supply, standards and compliance guidance are “inadequate” and she has made a series of recommendations, including a specialist task group.

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The industry has said there is no evidence that fume events cause lasting harm.

However, the union Unite is behind 10 cases which are heading to court later this year.

In a statement, the Civil Aviation Authority said: “The overall conclusion of independent studies and evidence reviews is that there is no positive evidence of a link between exposure to contaminants in cabin air and possible acute and long-term health effects, although such a link cannot be excluded.”