And most likely it is not because of the smelly feet and socks of the person next to you. The smell is too long lingering to be the frequent passing of ‘wind’ which many of the flying public suffer from. Neither is it the smell emanating from open toilet behind (or in front of) you.
The problem may very well be “cabin contamination”, also known as “bleed air contamination”. In the cabin of a flying plane, the air that passengers and crew breathe is continuously pumped in and out of the cabin through mechanisms that flow through the engines of the aircraft. As the engine turbine turns, fresh air is sucked in or out of the plane. Ideally that is the case. However, ever since the 1950s problems have been reported with air being contaminated with fumes from the engine, and worsened in the 1960s after the air circulation systems of commercial jetliners were designed to draw cabin and flight deck air supply from the engines and auxiliary power unit (“bleed air”):
Aircraft rely on engine bleed air to pressurize cabins, provide ventilation and other uses. Once compressed, the air is cooled and sent into the cabin and cockpit. About 50% of the air in a plane’s cabin is bleed air, and the rest is filtered recirculated air. Cockpits sometimes use 100% bleed air (source: WSJ).
An episode of Zembla (Gift in de cockpit—Poison in the cockpit) drew attention to the seriousness of the problem in the Netherlands and with the Dutch airline KLM. A maintenance technician with KLM, who has been concerned about the problem for some time says the issue falls on deaf ears within the airline:
“It is not the airline companies that keep this quiet, but the industry as a whole. A number of aircrafts are notorious: the [Boeing] 757, the Bae 146, and the Fokker 100 and 70. The Fokker engines of Rolls Royce always leaks. It’s the seals, the rings, and the lower chambers of the compressors. If those leak, there can be oil fumes can enter the supply of air [into the cabins].
A report by the UK’s Civil Aviation Authority admits:
It was clear that the BAe 146 was not the only aircraft type affected and that the Boeing 757 had also been similarly affected. Report of other aircraft types such as the F100 [Fokker], A320/321 [Airbus], B737 [Boeing] and DHC-8 [De Havilland] experiencing "fumes" although not to the same extent.
A former pilot of the BAe 146 testifies:
Any BAe 146 pilot will confirm that the smells on the aeroplane, particularly on the ground before flight are very bad. I have reason to believe that these smells are not good for any occupants on board. The smells originate from the air conditioning system and on bad days can be seen as feint blue fumes in the cabin for the first 10 - 15 minutes before actual flight, it tends to clear - just before the passengers arrive.
Around the world there have been many reports of such problems (see especially pp. 10-13), but often pilots are scared to come out and speak about it. A former KLM pilot, speaking under the condition of anonymity reports that especially the Fokker planes of KLM (more specifically, its subsidiary Cityhopper which operates 5 Fokker 100s, 26 Fokker 70s, and 5 Fokker 50s on European regional routes. I had the (mis)fortune of flying on one of these planes.) suffer from the problem of cabin contamination:
It happens regularly that the cabin really smells. It is the [smell of stinking socks]. Just recently, my co-pilot got a bout of severe coughing. Personally I had irritations in my nose. […] Sometimes even the passengers complain about the stench. There are technicians who say that you are just breathing in oil.
The UK’s Department for Transport reports that since 2001, there have been some 36,000 complaints about the problem, and assures the public that only 0.05% of flights a(or 1 in 2000 flights) are affected. Though an expert neurologist interviewed in the programme says that the risk to occasional fliers may not be so high, airline crew and frequent business fliers must be aware of the problem. At least three former KLM pilots are filing a claim against the airline. A briefing prepared by the UK’s House of Commons:
Dr Sarah Mackenzie Ross, a clinical neuropsychologist at the University of London, says the illness could be affecting up to 200,000 passengers a year. Many experts and campaigners consider that a conservative figure. In January this year, investigative journalists from German and Swiss TV secretly took 31 swabs from aircraft cabins on popular airlines. These were analysed in the laboratories at the University of British Columbia under the supervision of Professor Christian van Netten, a leading toxicologist. Twenty-eight of the swabs were found to have dangerously high levels of TCP.
A Dutch toxicologist interviewed in the programme, especially as a hazardous neurotoxin known as TCP (found in, among other things, chemical weapons) are present in engine oil used in commercial aviation. Exposure to such the neurotoxin leads to “tunnel vision” and the feeling of dizziness. Further, heated engine oil often results in chemical reactions that release a toxic chemical called trimethylolpropane phosphate, which can lead to convulsions epileptic attacks (and in the case of mice, convulsions followed by death). A French report cites that the extended exposure to the “smelly sock” fumes can result in infertility and pose a threat to the unborn child. Report by the European Aviation Security Agency on the symptoms of cabin contamination:
This ranges from benign symptoms like unpleasant odour, light eye or nose irritation, light headache up to more serious symptoms like severe headache, difficulty to concentrate, nausea or muscle cramp. The most serious symptoms can substantially degrade flight crew awareness and performance of their duties. Then, the main associated safety threat would be a dual and simultaneous pilot incapacitation occurring during a critical phase of flight such as take-off or landing, which would be potentially catastrophic [emphasis mine].
As a former British Airways pilot describes it, the smell is sometimes very faint, but resembles that of a “wet sock, wet dog, or gymnasium type of smell”. A source of the problem is the use of lubricant oil to lubricate parts of the engine. When a seal is broken or worn, it is often difficult to address the problem without taking the whole engine apart in a specialist hangar—which can be a costly and time consuming endeavour. So often airlines would continue to fly the aircraft, even though leakages exist.
One reported incident is case of flight KL1540, from Leeds to Amsterdam on 2 December 2009. Shortly after taking off, the 23 year old Fokker 100 (registration: PH-OFE) returned to Leeds due to problems with the air quality, which prompted the pilots to put on their oxygen masks. In the logbook of the plane were written the words: “Crew dizzy”. A few weeks after the incident, the problem occurred again, and this time it was so severe that the plane was returned to Amsterdam without any passengers on board. One of the engines was replaced, but the problems of engine fumes returned shortly afterwards. A KLM technician on the little Fokker:
The machine still has dealing with complaints of “wet socks”, which does not surprise me. The engine, used to replace the [old one], comes from a machine which also suffered from the same complaint”.
An investigation by Fokker after the incident recognises that it was a “serious complaint” but assures that there are no serious problems with the plane. Fokker admits that the investigation only conducted measurements into the quality of the airflow and the temperature in the cabin, but whether toxic oil fumes are leaking into the cabin was not measured. In response to whether such planes should continued to be flown, Vice President of Fokker says:
If KLM decides that an aircraft can fly, and I am the passenger and I go sit onboard, then we fly […] [the reliability of the Fokker fleet] is only getting better, so I do not have a single problem with it. I’m going to fly in every Fokker there exists. […] The airline company makes the decision whether it is safe to fly.
KLM denies that there has ever been a situation through which exposure to toxic fumes placed the safety of the crew or passengers at risk. In a written response, KLM states: “Only aircrafts of which we know are 100% safe are permitted to fly […] The quality of the air on board our airplanes are constantly checked”. Even so, KLM does not allow any interviews to be conducted with pilots or technicians at Schiphol. Spokesperson for KLM: “We do see the reason [for an interview]. Exactly because from our perspective maybe there is less [of a problem] than what other people assert”.
The airline and Fokker attribute the problem of “smelly sock” to and fungus and bacterial formations—and because of not oil leakages. Vice-President of Fokker attributes the smell on water on board the aircraft:
In the plane there is a lot of water […] so we have throughout the years brought about some changes to ensure that the plane remains as dry as possible, and that no blankets become wet and so on. […] The complaints [about smelly socks] keep on coming, so we have to keep on [investigating].
Since 2007 the Dutch Transport and Water Management Inspectorate reports that there has been 17 reports of problems with stench inside the cabin “possibly due to engine malfunction or problems in the air conditioning […] There are 13 reports in which the crew or the passengers became unwell. The Inspectorate takes these sort of reports extremely seriously”. Even so, it is up to the airlines to self-report the problem, which is unlikely to happen.
Indeed, associations such as the Aerotoxic Association and the Global Cabin Air Quality Executive warn of the serious nature of the problem. Not only is “bleed air” linked to physical and neurological problems, worse is that the aviation industry, comprising of airlines and manufacturers, are colluding to cover up the problem:
4. Aircraft have no detection equipment for contaminated air yet aircrews are not required to even have a sense of smell to be able to fly. Many compounds present in contaminated air are also odourless like carbon monoxide.
5. The breathing air for passengers and crews comes from ‘bleed air’ in flight, which is taken from the engines. This is not filtered and is known to become contaminated with engine oils and hydraulic fluids.
7. Airlines do not tell passengers they have been exposed to contaminated air and never check up with exposed passengers to investigate any medical effects of exposure after an event.
8. Airlines fail to warn passengers of the serious health effects that can occur from exposure to contaminated air.
9. Most passengers assume the air they breath is free of hazardous chemicals as they trust the airline they fly with to supply clean air. Should they get sick, few if any ever make the link.
10. The CAA is entirely funded by the airlines it regulates. This results in a serious conflict of interest. This has resulted in the CAA dealing with the ongoing contaminated air exposure issue in a negligent manner. The CAA in this regard fails to protect the travelling public and working crews.
14. Serious failures in flight safety have resulted from exposure to contaminated air as few crews actually use oxygen when they suspect the air is contaminated as they ought to. The airlines and CAA know this, but do nothing to rectify this hazardous condition. Why? As to do so, would be costly to the industry.
No comments:
Post a Comment