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Can this controversy over bleed air become a significant factor in airline economics? Can you imagine a day when large numbers of air travelers choose to route their long haul flights so they can ride the Dreamliner (which doesn't use bleed air)?
For example the new low cost carrier norwegian.com currently has 15 routes connecting four European cities and five USA cities. All flights are done with Dreamliners, and more are being added monthly. In contrast United is usually it's Dreamliners on the Asian and Australian routes with only the Houston to London route being the sole USA-Europe route to use this aircraft.
Last edited by PacoMartin; 10-06-2014 at 02:46 AM..
Can this controversy over bleed air become a significant factor in airline economics?
The engine compresses and heats bleed air. There is always the chance that things you do not want to breath are making it into the cabin. In addition the air cycle machines are lubricated by engine oil. There is always the chance that some oil is making it past the seals and makes it into the cabin.
From the little bit that I know about the electric compressors on the 787, it sounds like a better method than using engine bleed.
However, that trailer for the movie was quite ignorant. It is not like there has been some conspiracy to endanger the lives of passengers since the invention of cabin pressurization. It was simply the accepted way of accomplishing it. And it is unreasonable to think that all airplanes can be retrofitted with new systems.
Why not claim that all aviation deaths could have be eliminated if it weren't for the conspiracy of the airlines to make people fly instead of using rail & oceanliners for travel?
The whole point of electric fans on the Dreamliner was to remove as much parasitic bleed from the engines as possible - making them more fuel efficient. Yes, the air that you breathe on a plane comes from the engine (sort of - there's a lot going on in an aircraft AC system) and in order to do that, they basically have "ports" that tap off of the engine at various locations and stages. Although there's still plenty to go around, engine manufacturer's have always referred to this as "parasitic bleed" due to the fact that it's still pulling air off the engines.
It really has almost nothing to do with the air you breathe.
The offending chemical is called an organophosphate. It's produced in mist form by oil seeping past seals internally in the engine's compressor section. Seals are seated by bleed air, which if there is a leak forces oil out past the seals and into the on-coming air which is then tapped for cabin pressurization after running through a machine known as an "air cycle machine" or PACK.
When heated and misted the fumes are ingested by passengers. Studies have shown roughly 3% of the population is effected by organophosphates, which is why only a few people are disabled when an event happens. The substance is essentially a neurotoxin, and is incredibly dangerous especially in heated and misted form.
One previous airliner that did not use bleed air for pressurization directly are DC-8's, but they have long since been retired from commercial service.
This problem has been seen mostly on BAe 146 and Boeing 757s, however all makes and models (Boeing/Airbus) are not excluded and there have been events on all types of aircraft. A recent estimate I saw is that it happens once every 2000 flights or so.
Another industry where organophosphates are used extensively is in the sheep farm industry. Sheep are "dipped" in chemicals containing organophosphates to counter a parasite that eats away at sheep's skin. The process is known as "sheep dipping", and similar issues have been documented amongst farmers.
I wasn't asking about the actual health risk. My question was about the perceived health risk. People regularly cancelled flights on turboprops because they felt unsafe. There was an economic impact.
As far as I know, concerns about "bleed air" rank way below ticket price, air time, and frequent flyer miles. But until basically this year there was not an option. It is now possible to go many places on Dreamliners, but not flying the airlines you may be used to. Also you may have to change planes in Oslo or Copenhagen instead of in the USA.
Can you imagine a situation where fear and paranoia could reach a level that a significant percentage (say 10%) of passengers refuse to fly long distances unless they are in a Dreamliner? Or do you feel that this issue will remain a fringe concern?
Last edited by PacoMartin; 10-06-2014 at 02:19 PM..
I wasn't asking about the actual health risk. My question was about the perceived health risk. People regularly cancelled flights on turboprops because they felt unsafe. There was an economic impact.
As far as I know, concerns about "bleed air" rank way below ticket price, air time, and frequent flyer miles. But until basically this year there was not an option. It is now possible to go many places on Dreamliners, but not flying the airlines you may be used to. Also you may have to change planes in Oslo or Copenhagen instead of in the USA.
Can you imagine a situation where fear and paranoia could reach a level that a significant percentage (say 10%) of passengers refuse to fly long distances unless they are in a Dreamliner? Or do you feel that this issue will remain a fringe concern?
Unless it becomes a more widespread problem I'm sure it will remain a fringe concern. I believe a more likely scenario would be passengers worried about flying the Dreamliner with the bad press its received rather than worrying about potential bleed air problems they probably don't know exist.
This has been known for some time, but there just isn't a lot of info about it. Google 'aerotoxicity'. There is evidence that it may have long-term negative impacts upon crewmembers. On the 145, it was known among flight crew there would be times during which a 'dirty/sweaty sock' smell would fill the cabin, primarily during specific power settings. I was also flying when we had a 'fume event'. Had to turn around and make an emergency landing. We learned days later that the source was in fact lubricating oil contaminating the bleed air system. It was damn scary to be honest. Couldn't see ****e, had to don the O2 masks, smoke goggles, depressurize the cabin air because the smoke so chokingly thick. It even set off the lav smoke detector.
Edit (not flight I was on, but near exact circumstances):
Couldn't see ****e, had to don the O2 masks, smoke goggles, depressurize the cabin air because the smoke so chokingly thick. It even set off the lav smoke detector.
I could see this having an economic impact.A Boeing technical article does not mention health concerns, only engineering efficiency.
Quote:
Originally Posted by Boeing technical article
In the 787 electrical architecture, the output of the cabin pressurization compressors flows through low-pressure air-conditioning packs for improved efficiency. The adjustable speed feature of electrical motors will allow further optimization of airplane energy usage by not requiring excessive energy from the supplied compressed air and later regulating it down through modulating valves resulting in energy loss. Avoiding the energy waste associated with down regulation results in improvements in engine fuel consumption, and the environmental-control-system air inflow can be adjusted in accordance with the number of airplane occupants to achieve the lowest energy waste while meeting the air-flow requirements.
I don't know if airlines would subtly work this into their advertising. No airline would dare to make this a front and center issue, as there is no such thing as an airline that has an "All Dreamliner" fleet.
However, Norwegian Air Shuttle's entire long haul fleet consists of Dreamliners (7 today, with 10 more on order). ANA (the Dreamliner's launch customer) is phasing out their fleet of Boeing 767's, but they have a considerably large 777 fleet.
The 737 MAX will have a new digital regulator for the engine bleed air systems which should improve its reliability.
Aeromexico will have a mostly Dreamliner long haul fleet in a few years, but for most people the idea of flying from the USA to Mexico City to get to London, Paris, Madrid, Tokyo, or Shanghai seems like a lot of trouble.
However, Air Canada has 4 Dreamliners delivered and 34 more on order. People would probably be willing to fly to Toronto to take long haul trips.
About one in eight Dreamliners on order are scheduled to go to United/American/Delta. Only United has received any Dreamliners to date, and they are mostly flying to Asia/Australia .
I don't envision a significant percentage of air passengers insisting on aircraft without air bleed systems. But I could imagine an "fume event" happening where passengers will refuse to fly on older long haul aircraft like the B747, B757 or B767.
Air Canada (AC) Dreamliner International Routes October 2014
Toronto (YYZ) – Copenhagen (CPH)
Toronto (YYZ) – London (LHR)
Toronto (YYZ) – Tel Aviv (TLV)
Toronto (YYZ) – Tokyo (HND)
Toronto (YYZ) – Vancouver (YVR)
Toronto (YYZ) – Zurich (ZRH)
Vancouver (YVR) – Shanghai (PVG)
So instead of flying to JFK to change planes for TelAviv, the customer might choose to change planes in Toronto so that he can ride a Dreamliner.
Last edited by PacoMartin; 10-06-2014 at 05:39 PM..
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