Can the air on your plane harm you?
A former pilot is campaigning to get the airline industry to believe that there is a health risk for passengers and flight crew from fumes when air is pumped into the plane during a high pressure oil leak in the engine.
Tristan Loraine always wanted to be a pilot. From the moment he first saw the 1969 film 'The Battle of Britain' when he was seven years old, his mind was made up.
"I remember going to watch the film Battle of Britain and came out and thought that Spitfires were planes that would come along and spit fire at other people.
Tristan Loraine - health fears.
"I was really focussed and motivated to do it," said Tristan.
"When I was 17 I used to get a bus for two and a half hours up to the international airport and used to have flying lessons and that’s when the dream got on its way."
But 30 years on, Tristan, from Horsham, Sussex, has retired through ill-health, poisoned, he says, by contaminated air.
He is now campaigning to get the airline industry to believe that flight crew and passengers are at risk from the chemicals which he says are pumped into modern jet aircraft every time there is a high temperature oil leak from the engine – known as a "fume event".
Contaminated cabin air?
Tristan is not alone.
Other pilots and flight attendants are also convinced that contaminated cabin air has left them with serious neurological problems.
Air is sucked into the plane by the engines.
One former pilot even blames cabin air for his motor neurone disease.
For about 50 years, jet aircraft have taken the air passengers and crew breathe from the engine.
Known as "bleed air", it is sucked in by the turbines into the engines before it is fed into the cabin.
The campaigners' concerns centre around tri-cresyl phosphate, an organosphosphate added to aircraft oil to help reduce wear on the engine.
There are a number of chemicals in the oil which may act together or independently which may put people at risk.
No long term risk?
But the aviation industry says there is no proof of any long term health risks.
Indeed it claims that an investigation by an independent committee appointed by the government said there was no evidence of long term ill-health to crew.
However, the Committee of Toxicity, set up by the government to provide independent advice, has recommended that flights be monitored for the presence of chemicals originating in oil.
Monitoring is expected to start later in 2008, though scientists will only look at a few hundred flights and campaigners say the chance of there being a fume event while the monitors are on board is slim.
Dr Sarah Mackenzie Ross, of University College London, one of the leading experts on the effects of toxins on the brain, wants to survey 1,500 pilots to find out if there is a link between pilot health and contaminated air.
She says, "It’s really important that this is researched and researched quickly. If there is a link between contaminated air and ill-health then it's a major air safety issue."
Disorientation on descent
The Air Accident Investigation Branch (AAIB) has examined reports into fume events and has documented the effects contaminated air has had on pilots.
One report in 2006 said, "During the descent, both crew members began to feel disorientated and found that they had to concentrate hard to carry out their normal duties. At this point the commander began to feel 'confused'."
Airlines say there are no alarming trends in sickness rates among crew and they would never knowingly operate an aircraft which posed a health or safety risk to either passengers or crew.
The industry says there have been no proven cases of contaminated air poisoning in 50 years and that improved engine design has reduced the risk of oil leaks.
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last updated: 03/03/2008 at 16:06