American Airlines Flight 109, traveling from London to Los Angeles, was two hours into its flight when passengers and crew members suddenly started fainting or otherwise becoming ill.   The captain turned the Boeing 777 around and landed at Heathrow. American Airlines 777 

According to the Daily Telegraph in Britain, the aircraft likely experienced a problem with the aircraft’s pressurization system: 

This would suggest problems with cabin pressure, although normally such problems occur during take-off and landing.

American Airlines added that the aircraft was being inspected by maintenance engineers.

Actually, what happened was likely a “fume event.”  For years, the airline denied fume events existed, but now we know that they do.  And we know that they are dangerous.  In fact, I wrote about a fume event aboard another American Airlines Flight (Flight 49) almost five years ago.  

Here’s what happens: airlines pump air into the cabin.  The air is a mix of fresh air and air that has been compressed by the aircraft’s engines–known as "bleed air."  But when the air distribution system malfunctions, toxic chemicals found in the aircraft’s engine oil can be heated and pumped through the airplane, creating a fume event that makes passengers sick

Sometimes the passengers recover quickly, sometimes the ill effects can linger for years, with victims suffering ongoing tremors, memory loss, and headaches.   

If they are injured, passengers can recover against the responsible airline.  Because American Airlines Flight 109light was international, the Montreal Convention applies.  The Convention requires an airline to offer fair compensation to anyone injured as a result of an "accident."  A fume event would likely qualify as an accident, even though some airlines now contend that fume events are a "normal” part of flight.

The flight attendants, however, can’t sue the airlines due to workers’ compensation laws. That means their only chance for compensation is a product defect claim against Boeing, the aircraft’s manufacturer.  As it turns out, Boeing has known about the risks of fume events in its designs since the 1950’s.

The air in an airliner’s cabin has been compressed by the aircraft’s engines. Most of the time, the air is safe to breathe. But if a leaky seal in the engine allows the air to first mix with heated engine oil, the cabin air can be contaminated with toxic fumes.

When a cabin fills with toxic chemicals from an engine’s bleed air, it’s a "fume event." For years, Boeing denied that fume events occurred at all. Then, it conceded fume events happened, but denied that they were dangerous.  

Terry Williams was an American Airlines flight attendant. She says the chemicals she breathed during a fume event in 2007 caused her debilitating tremors, memory loss, and headaches. When Boeing denied that a fume event could be responsible for William’s illness, Seattle aviation attorney Alisa Brodkowitz filed suit on Williams behalf.

What Brodkowitz uncovered created an uproar. As it turns out, Boeing has known about the risks since the 1950’s. But instead of fixing the problem, Boeing just covered it up.

According to Brodkowitz, Boeing has made no attempt to keep the flying public safe from fumes.

To this day, the only thing filtering this toxic soup out of the cabin are the lungs of the passengers and crew.

This week Boeing settled Williams’ lawsuit. But it still denies any liability. Alhough Boeing insists it is safe to breathe the cabin air in its aircraft, it nonetheless designed its new 787 Dreamliner so that the cabin is pressurized without using a bleed air system. 

Good idea. 

A cabin suddenly fills with fumes.  Passengers get ill.  The fumes eventually clear.  But for some, the symptoms persist long after the flight is over.  Others will first develop symptoms weeks or months later, and may not even relate their symptoms to their flight.  These passengers are all the victims of what has become known as a "fume event."

Here’s what happens: Airlines pump air into the cabin.  The air is a mix of fresh air and air that has been compressed by the aircraft’s engines–known as "bleed air."  But when the air distribution system malfunctions, toxic chemicals found in the aircraft’s engine oil can be heated and pumped through the airplane, creating a fume event. Bleed Air Schematic According to the Wall Street Journal:

Airline companies and jet manufacturers say that fume events are rare, and that when they do occur, air quality still exceeds safety standards. But unions representing pilots and flight attendants say the chemicals entering the aircraft cabin can endanger the health of flight crews and passengers.

For years, the airlines denied that fume events occurred at all  Then, the airlines admitted the events occurred, but denied that they were dangerous.  But fume events appear to be happening with more and more frequency, and the airlines seem to be more willing to admit that there is a danger to the flying public.  Regardless, in March the US Senate approved a measure that would require the FAA to study cabin air quality generally and fume events in particular.

The increased focus on fume events is for the most part due to injuries that American Airlines flight attendant Terry Williams suffered in April 2007.  She recently filed a lawsuit against Boeing, the manufacturer of the aircraft on which she was flying.  Williams is represented by Alisa Brodkowitz, a prominent aviation lawyer in Seattle, who is perhaps the nation’s leading expert on fume events.

What about the passengers of American Airlines Flight 49, who were involved in a fume event today while travelling from Paris to Dallas-Forth Worth? 

Because the flight was international, the Montreal Convention applies.  The Convention requires the airlines to offer fair compensation to anyone injured as a result of an "accident."  An accident is an "unexpected or unusual event or happening" on board the aircraft that is "external to the passenger."  A fume event would likely qualify (though some airlines contend that fume events are "normal".)

The flight attendants will have a tougher go of obtaining compensation for any long lasting injuries they might have suffered.  They can’t sue the airlines due to workers’ compensation laws.  That means their only claim is a product defect claim against Boeing, the aircraft’s manufacturer.