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Aerotoxic in the news

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Aerotoxic in the news

Old 24th Mar 2015, 20:00
  #261 (permalink)  
 
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A few little statistics for you.....
Personally, I would not call anything that followed any sort of "statistic", just a long litany of anecdotal experiences with really questionable correlation and zero causation.
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Old 24th Mar 2015, 20:59
  #262 (permalink)  
 
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Anyone want to take any guesses as to why the B787 (and I think A350) use compressors for cabin pressurization/air conditioning and NOT engine bleed air? More weight and more complexity. They're not doing it to save money or fuel...
They're not doing it to save fuel? Really? More weight? Really? Yet more conspiracy theories based on faulty/incomplete information. As for complexity, the 787 approach requires very complex electronics while tremendously simplifying the airplane mechanically. Electronic technology has come a long way baby, and it now makes sense to replace mechanical systems with electric ones.

And guesses? No guessing is needed. Here's the reality. An aircraft can be pressurized by extracting horsepower or extracting bleed air. Reciprocating engine aircraft have no bleed air so you extract horsepower to turn a compressor which pumps air into the aircraft. Such compressors are not too efficient and may not be reliable. Jet aircraft are already equipped with a VERY efficient compressor in the form of the engine itself, so extracting bleed air is more efficient AND more reliable. Most turbo prop aircraft also use bleed air because of the efficiency, but there are some exceptions. The L-188/P-3 for example had separate engine driven compressors on the inboard engines and did not use bleed air for pressurization.

But there is no free lunch. Extracting bleed air makes the engine less efficient. Plus the bleed air must be cooled and routed to the air packs in the fuselage, resulting in heavy, costly, and complex intercoolers, bleed air plumbing and mechanical systems. Suppose you could replace all that with some electric wires? The 787 does just that.

The 787 has no bleed system and no engine driven hydraulic system. EVERYthing runs on electricity. The 787 has two HUGE generators per engine. This tremendously simplifies the engine nacelle design since all that is needed is wiring to run the power out of and into the engine nacelles. Into? Yes. The generators are motor-generators and when you apply power to them from a ground source, they generate horsepower to start the engines. Thus no bleed air to start the engines nor to run the cabin pressurization. Same story for the APU. And no bleed air for anti/deice systems.

Again, there's no free lunch. The massive generators have HUGE horsepower extraction. Extracting bleed air stabilizes a jet engine. Extracting horsepower destabilizes it. Extracting this level of horsepower from a jet engine has only become possible with the advent of FADEC (digital engine controls). And motor-generators of this size have only become possible with the advent of VSCF generators which require VERY high power solid state electronics.

Boeing chose a high risk path to maximize the efficiency of the 787 both in terms of structure AND in terms of systems. The airlines dragged Airbus kicking and screaming to adopt a risky composite fuselage for the A350, but could not get them to accept the risk of all the high-tech systems of the 787. That extra risk cost Boeing dearly, but it is now starting to pay off and should pay back more and more over time. The weight savings of going (near) all electric, along with the improved efficiency of the engines due to elimination of bleed air provides an overall 2% to 3% efficiency improvement. And while bleed air pressurization systems have maxed out efficiency wise with essentially no more gains possible, the electric pressurization system in its infancy EQUALLED the efficiency of the bleed air pressurization at full maturity and is certain to continue to improve over time.

And here is the bottom line: despite claims/insinuations to the contrary by the scare mongers, Boeing's choices in the 787 had nothing to do with aerotoxic syndrome. NOTHING.
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Old 25th Mar 2015, 01:22
  #263 (permalink)  
 
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Originally Posted by Basil View Post
I have never had a 'toxic air' problem nor have I met anyone who has. It is, of course, possible that a very few people have a genetic predisposition to irritation caused by tiny concentrations of pollutants. It will be interesting to see how the B787 fares in this respect. My guess? Just the same.
Well I've had many toxic air events and also now fly the 787 . I feel a great deal healthier on the latter
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Old 25th Mar 2015, 04:23
  #264 (permalink)  
 
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Racing Snake, the 787 is - by design - pressurized to a lower altitude (5k, vs. 8k for most aircraft) and higher humidity. This is unrelated to how the aircraft is pressurized - it's primarily due to the carbon composite primary structure of the aircraft. Lower altitude/higher humidity, especially on a long flight, will most definitely make the average passenger feel less fatigued and "healthier" relative to the normal higher/drier air. Or in short, your feeling better after flying on a 787 likely has nothing to do with how the aircraft is pressurized.
Out of curiosity, I've been looking through the last several months of the Boeing 21.3 reported 'fume events'. Most have had nothing to do with the engines - electrical system/overheats being the dominate cause, closely followed by something burning in the galley. A few were no fault found, and one was the next flight after an engine water wash (presumably a missed step in the wash procedure introduced water wash related contaminates into the bleed system). None, as in ZERO were reported as having been associated with an engine oil issue.

As others wrote, the 'no bleed' configuration of the 787 was for efficiency - some high level people at Boeing believed that designing the high compressor without compromise for ECS bleed off take would provide significant efficiency improvements. That part didn't really pan out all that well (the high pressure compressor of the GEnx-2B on the 747-8 with ECS bleed is basically identical to the high pressure compressor on the GEnx-1B on the 787 without bleed, and the TSFCs numbers are not much different).
But let us postulate for a minute that Boeing saw the data and determined that engine bleed air caused Aerotoxity was a major problem and needed to be addressed to avoid future liability and designed the 787 accordingly. Since the 787 was launched over 10 years ago, Boeing has made or committed to major updates of every Boeing commercial aircraft currently in production:
737 - 737 Max, new engines, significant avionics and systems updates
747 - 747-8 , new engines, new wings, significant avionics and systems updates
(757 has been out of production for over 10 years)
767 - 767-2C/KC-46 tanker - engine largely unchanged but significant structural, avionics, and systems updates
777 - 777X - new engines, new wings, significant avionics and systems updates.

Every aircraft involving $Billions$ in development costs. Easy, ready opportunity to introduce non-engine bleed cabin pressurization systems across the product range, plausibly explained by improved fuel burn (as on the 787) without admitting potential liability. Or they could wait until fully implemented then throw it out that Airbus engine bleed pressurization is dangerous (or at least unhealthy) as a massive competitive advantage.
Result? The 737 Max, the 747-8, the 767-2C/KC-46, and 777X all use engine bleed for aircraft pressurization. The 787 will remain - for the foreseeable future - as the only commercial jetliner to not use engine bleed air for cabin pressurization.
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Old 25th Mar 2015, 08:43
  #265 (permalink)  
 
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Thx for your informative reply tdracer, always interesting to read!

(the high pressure compressor of the GEnx-2B on the 747-8 with ECS bleed is basically identical to the high pressure compressor on the GEnx-1B on the 787 without bleed, and the TSFCs numbers are not much different).
Result? The 737 Max, the 747-8, the 767-2C/KC-46, and 777X all use engine bleed for aircraft pressurization. The 787 will remain - for the foreseeable future - as the only commercial jetliner to not use engine bleed air for cabin pressurization.
But wouldn't that make any testing much easier? For as far as I know, the 777 and 787 are flown mixed fleet, so couldn't a mid-long term study easily show that on a consistent basis crews deplaning after a 777 flight have perhaps different toxins in their blood/urine, than a 787 crews deplaning after a flight? After all those GEnx engines are almost identical, except for the bleed air extraction, correct?

Perhaps this would not be an all conclusive study because other factors need to be ruled out, but wouldn't it be a huge step in the right direction and definitely shed some light on this issue?
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Old 25th Mar 2015, 20:08
  #266 (permalink)  
 
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But wouldn't that make any testing much easier? For as far as I know, the 777 and 787 are flown mixed fleet, so couldn't a mid-long term study easily show that on a consistent basis crews deplaning after a 777 flight have perhaps different toxins in their blood/urine, than a 787 crews deplaning after a flight?
Apparently not. According to the aerotoxicity folks, one cannot test for TCP in the blood or urine. The kidneys and liver break them down and all you can test for is the metabolized remnants of TCP.

But you can sample the air in both aircraft and test for TCP levels (which, contrary to what the scaremongers claim, is being done right now by various agencies.) Thus far numerous tests have already shown that TCP levels in aircraft are already thousands of times lower than required thresholds. What if the 787 TCP levels turn out to be tens of thousands times lower (or only hundreds of times lower) than the threshold? What does that prove?

And BTW, the electrically driven compressor on the 787 uses the same lubricating oil as the engine. So I don't understand the whole fixation on the alleged superiority of the 787 in the first place.
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Old 25th Mar 2015, 21:41
  #267 (permalink)  
 
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I am a passenger who suffered cognitive impairment, nausea, dizziness for 5 days after smelling variety of strange odors in the cabin. And many people around me at the flight suffered the same with heavy vomiting and loosing consciousness. I complained to the company but they completely ignored me.
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Old 25th Mar 2015, 21:55
  #268 (permalink)  
 
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Anyway, what are the impediments of putting sensors in the cockpit? apart from TCP it could be de-icing liquid or other things
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Old 26th Mar 2015, 12:29
  #269 (permalink)  
 
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Denial

Please wake up Ppruners.

Some of you are remaining deep in denial, fueled, it seems by basic industry supported smoke and mirrors research.

Images pasted below of an open letter by Dr. Jean-Christophe Balouet. He is not happy about the "Smoke and Mirrors" research as mentioned above.

I have highlighted some really simple stuff on page 3, one company sponsored research project used water based wipes to collect samples from cabin walls. We all know that these chemicals dissolve very badly in water, you need alcohol wipes to take a swab for test.

Why would the company do this?

http://imgur.com/NbfI5C7
http://imgur.com/NwQ4cHs
http://imgur.com/Dg8hNEH
http://imgur.com/r6Jxpn8

This stuff is so utterly simple, you have 10 chemicals to test for and only test 5 that you know will give low results. You know you need to use an alcohol swab and so you use a water based one, you have a fleet of smelly Aircraft and test another type etc etc.

I am simply not gullible enough to fall for this stuff, I never was. This is what made me a "safe" Airline Captain. Unfortunately I am no longer a "safe" Airline Captain, if I had tried to continue with the cognitive impairments I suffered I believe this would have led to an accident.

For Iron Lady, welcome to PPRuNe, get tested, links above in my posts, if any positives, contact a Lawyer, Frank Cannon named in my posts above. You may well have long term health problems from your single exposure.

Another Ppruner above asked, "how will we put this genie back in the bottle"? Very simple, fit filters (one UK based freight company allegedly has already), pay off the wrecked Pilots and Crew, carry on designing Aircraft without connecting potentially dirty bleed supplies to the cabin.

It may cost a billion to pay off the victims, this is only the cost of four large long range Aircraft. It may add $5 to the cost of every flight.

Lastly, in another post above, one poster is suggesting that B787 Pilots feel better due to the cabin altitude being kept to 5,000ft not 8,000ft. This is really clutching at straws. Please note my post above about spending a week at a 10,000ft ski resort with no ill effects. Please all take the time to find yourself a B787 Pilot and ask them how they feel after a long flight.
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Old 26th Mar 2015, 15:25
  #270 (permalink)  
 
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Beyond help, methinks.
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Old 26th Mar 2015, 16:20
  #271 (permalink)  
 
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KenV, I don't know where you've gleaned your information from, but Trent 1000's that are used on the 787 most definitely have one engine driven hydraulic pump (per engine).
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Old 26th Mar 2015, 16:51
  #272 (permalink)  
 
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787 Engine Hydraulics

Look at - http://www.ata-divisions.org/S_TD/pd...ngtheB-787.pdf

Page 28 shows engine driven pumps, surprised as I thought it was all elect power takeoff.
As a retired avionics mech at BA LHR I like to keep my eye on things. I would get out more but there there are too many planes flying over................
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Old 26th Mar 2015, 18:04
  #273 (permalink)  
 
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Some of you are remaining deep in denial, fueled, it seems by basic industry supported smoke and mirrors research.
As I have said before, if you remove your tin-foil had and present reasonable, scientifically valid, arguments then you will probably gain a lot more support than your current swivel-eyed method of communication.
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Old 26th Mar 2015, 18:42
  #274 (permalink)  
 
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Please note my post above about spending a week at a 10,000ft ski resort with no ill effects.
Perhaps it depends on how you define "ill effects", but I spend a couple weeks at a 10,000 altitude ski resort every year. These are some of the effects that myself and my family/friends commonly experience at 10k (usually worse for the first day or two, gradually improving as the body starts to adapt):
Shortness of breath
Accelerated heart rate (my normal 55-60 resting pulse goes to 85-90, and the slightest physical activity pushes it over 100).
Chronic headaches
Difficulty sleeping
Dramatic changes in appetite
"Altitude Sickness" (my wife once ended up in the emergency room, and a relative in the hospital, due to altitude sickness).

Sorry, but comments like what I quoted above are not helping your credibility.
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Old 28th Mar 2015, 21:01
  #275 (permalink)  
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The BA flight from Antigua to Gatwick diverted to Shannon this morning due to fumes on board:

http://clareherald.com/2015/03/28/jet-diverts-with-burning-smell-on-board-96312/
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Old 28th Mar 2015, 21:45
  #276 (permalink)  
 
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Boeing publications

Since I have now been told I am beyond help, swivel eyed etc.

Can one of the scientists above please tell me where the blue smoke that my Aircraft periodically filled with came from?

Also text pasted below from Boeing memorandum submitted to The UK House of lords in 2007. It clearly makes the initial statement that the bleed free architecture of the B787 was designed to eliminate fume events.

"The Boeing 787 will have a no-bleed architecture for the outside air supply to the cabin. This architecture eliminates the risk of engine oil decomposition products from being introduced in the cabin supply air in the rare event of a failed engine compressor seal. In addition, this architecture improves fuel efficiency, thus reducing fuel burn and associated engine emissions".

Full article link inserted below.

House of Lords - Science and Technology - Written Evidence

I must again reiterate my statement in the posts above, many of the AS deniers seem to have trouble reading technical documents and subsequently being able to understand the content.

There is also some question in regard to comprehension of my statement about feeling fine whilst spending a week at 10,000 feet at ski resorts, I personally do feel fine at these heights. I felt ill very quickly at less than 8000 feet in my Aircraft.

I also know a few former colleagues that get Eczema after every flight on their "dirty air" types. One has just converted to B787, guess what? No Eczema.

Please don't forget to try and debunk where my "blue smoke" came from and PLEASE read the House of Lords memorandum.
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Old 29th Mar 2015, 03:33
  #277 (permalink)  
 
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2 pesos from an epidemiologist

I am not a pilot but an epidemiologist. When I first caught sight of this discussion, it piqued my interest, though I was, and remain, skeptical. The epidemiological challenges regarding aerotoxic syndrome are, in my opinion, many and varied.


First, there does not appear to be a solid description of the endpoint itself. What is aerotoxic syndrome? What are the diagnostic criteria? Until these are defined and accepted, there is no chance whatsoever of doing any kind of meaningful or legitimate study of this phenomenon, if indeed it exists. I would use the highly technical term "squishy" to describe the cluster of symptoms that have been put forth as aerotoxic syndrome.


The second major issue in my opinion would be to ascertain if pilots as a group overall are suffering from an elevated risk of any disease at all. The answer from myriad scientific studies appears to be no--with one exception. As a whole, and despite what might arguably be called a high-stress work environment, airline pilots tend to have healthier hearts, fewer cancers, etc. as compared to the general population (links to peer-reviewed studies below). The only consistent finding of increased risk is for melanoma, which many of my colleagues have attributed to your ability to travel in patterns such as, say, the UK to Spain for Florida in the winter, during which time you may opt to fry yourselves on the beach or golf course. Others have hypothesized that it is cosmic radiation that it is the culprit.


Regardless, for the purposes of this discussion, you as pilots have been studied in fairly vigorous detail and don't appear to have higher rates of adverse health outcomes. This is key because it would seem that for some of the exposures being described in this thread, you might expect to see other adverse conditions popping up as well in response to those exposures.


I want to conclude by stating that my heart goes out to anyone who suffers from any health challenge, especially those that have been described herein, and some of which are devastating. It is especially awful when there may be no known cause, which is true for a staggering number of complex diseases even today. It is human nature to want to pinpoint the cause of one's illness, and it is also human nature to try to organize thoughts and experiences into patterns. A side effect of this tendency is that we sometimes see patterns where they don't exist. As of now, in my opinion, there appears to be very little compelling evidence for aerotoxic syndrome.


Cosmic radiation and cancer: is there a link? - PubMed - NCBI
Mortality among a cohort of U.S. commercial airline cockpit crew. - PubMed - NCBI
A study of airline pilot morbidity. - PubMed - NCBI
The risk of melanoma in airline pilots and cabin crew: a meta-analysis. - PubMed - NCBI
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Old 29th Mar 2015, 10:45
  #278 (permalink)  
 
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Since I have now been told I am beyond help, swivel eyed etc.
You see, this is the problem. You take everything on a personal level and fill it with your experiences, anecdotes, etc. That is not how a proper investigation can or should be done. It must be conducted dispassionately and with no external agendas.

While you obviously have strong feelings on the subject you are not doing yourself or the theory of aerotoxic poisoning any good with your posts on here. Posting a variety of completely unrelated points is also unhelpful. The point I am making is that all your posts on here seem very unconstructive and unhelpful. You also still fail to offer anything like proper evidence (how many times have you been asked for peer-reviewed evidence?)

Can one of the scientists above please tell me where the blue smoke that my Aircraft periodically filled with came from?
Why not ask an engineer?
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Old 29th Mar 2015, 14:21
  #279 (permalink)  

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"The Boeing 787 will have a no-bleed architecture for the outside air supply to the cabin. This architecture eliminates the risk of engine oil decomposition products from being introduced in the cabin supply air in the rare event of a failed engine compressor seal. In addition, this architecture improves fuel efficiency, thus reducing fuel burn and associated engine emissions".
Actually it doesn't
......clearly makes the initial statement that the bleed free architecture of the B787 was designed to eliminate fume events.
It clearly states that it is a product of the design not the clear purpose of the design.

Buy hey, what's a little mis-interpretation between friends?
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Old 29th Mar 2015, 14:56
  #280 (permalink)  
 
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Close this thread.

Close this thread.

It is quite simply a waste of typing and reading time.

Unless and until some real science is brought to bear by airframe manuf and Operators, the true TLV for many chemicals in planes will not be established.

Individuals who are suffering, and writing on here need to pursue personal sensitivity tests, and then the science route. Nothing will move by writing on here!!
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