Airborn Health Hazard

Fumes from the engines of jets are causing major concerns for both pilots & passengers. The fumes seem to be getting into the fuselage of the aircraft somehow and this is causing major illnesses were pilots have been reported to lose consciousness.

This issue has been known but is now becoming a focus for the aviation authorities.

The concept of what’s happening here makes me think of a car while on in a garage. Scary thoughts.


Ohhh, I do love a good, cherry picked, sensationalist journalistic headline!!!

Firstly, this has been an issue on ‘some’ gas turbines for many years and it is very nasty. However, it has nothing to do with exhaust fumes at all and everything to do with mineral oils, air conditioning and seals.

The issue is that some engines, in order to balance out the tremendous forces present within the aircraft engine, use a system called ‘thrust balancing’ to relieve the pressure on the main shaft bearings within the engine itself. This involves using some of the high pressure internal air to offset the forward thrust that the core of the engine is placing upon the engine bearings.

Modern gas turbines use a system that creates negative pressure at the seal thus ‘sucking’ any potential oil leak at the bearing into the engine core itself. Sadly older engines allowed positive pressure at the seals allowing, occasionally, misted oil loss into the engine ancillary systems. Which include a hot air feed to the air conditioning packs.

To summarise the contamination is caused by misted engine lubricants in the conditioned air in the cabin due to loss of integrity of thrust balancing seals. This is extremely nasty as most synthetic and non synthetic lubricants are carcinogenic!

However, the occurrence of such problems has been largely mitigated by clever engine design and, hopefully, future cases of this problem largely eradicated. Travel on certain older types of aircraft will have the potential to expose you to this risk though!

No exhaust gases. ;)


Great words, thank you for your input! It is reported that this causes major problems for airplanes on average at about about five times a day! That’s a lot!

I hope that they can fix the issue.

I believe most of the affected engines have been modified by now. I do know that this has been an issue on the 757/767 and the BAe 146.

Sadly I’m sure it will creep up again on some other aircraft. It seems that age related wear is a cause and, as such, these issues won’t come to light until later in the engines life span.


Very interesting, you seem very informed and extremely intuitive regarding this subject. Thank you.

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Very nicely explained😉

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