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Aerotoxic in the news

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Aerotoxic in the news

Old 20th Apr 2015, 10:51
  #381 (permalink)  
 
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When else could I be exposed to Tricresyl Phosphate?
As others have said there's many places you could be exposed.
So, you do not KNOW you were exposed on an aircraft. You ASSUME you were exposed on an aircraft.
And when an air sample from one of my companies aircraft was tested, from a calibrated air testing machine, in a laboratory, by a professor, it tested positive.
As has been said ad-nauseam on here it matters not whether a sample tests positive or not, it matters how much of the 'bad stuff' there is in the sample.
For example, I have a geiger counter sitting next to me just now and it 'tests positive' for radiation. So what? Small doses of radiation aren't a problem.
Small doses of Tricresyl Phosphate may not be a problem. The point made by some here is that we do not know what the limiting exposure is before these things become harmful. It also seems that a small minority of people are extra-sensitive to these chemicals .

Also, dropping "he's a professor" into the topic isn't very helpful. I'm a professor (in a different field, not medicine), so are some others in here. Why do you trust his opinion but not ours? Professors are just as good at being wrong as anyone else.

So, in short: "tests positive" is meaningless.
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Old 20th Apr 2015, 11:54
  #382 (permalink)  
 
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OK, I shall have to bow to your superior knowledge. I shall contact the three professors who have either done tests on my blood, on my body, and on the air I have breathed while on an aircraft. I shall tell Professor About-Donia that the tests he has done on me, and hundreds of other airline crew, have been a waste of time, because some industry apologist says so. Have you actually checked this guys credentials? You must be aware of the denial for years of Gulf War Syndrome. This is the guy who uncovered that problem. So when he tells me that I have "Organophosphate Induced Neuropathy" (the clue is in the title), I think I am justified in believing him. And when another professor tells me that my physical symptoms "can only be down to nerve damage", then I believe him. And the tests done a very "scientific". I have also seen a massive amount of evidence which confirms that Organophosphates are getting into aircraft cabins, a lot of which is to be submitted to the courts so I am not able to publish it. Let's get real, it's happening.
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Old 20th Apr 2015, 12:07
  #383 (permalink)  
 
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ASG

And hers's something from Air Safety Group for the naysayers to pull apart.
UK Air Safety Group (ASG) Statement on Airliner ?Cabin Air Quality? | Air Safety Group
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Old 20th Apr 2015, 12:41
  #384 (permalink)  
 
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TD racer

Silvertate, they are "leaking" that oil, but not in the manner you're thinking. Look at the core exhaust of your CFM engine, and you'll see a couple inch diameter pipe coming out the middle. For lack of a better term, that is the 'breather' or 'vent' tube for the turbine (internal plug nozzle use that tube, external plug nozzles simply have a hole in the back of the plug).

You'll find for most engines, the oil consumption is highest at idle - as noted before differential pressure is used to help keep the oil from leaking, the (relatively) low differential pressures at idle don't do that as effectively as they do at power.
What tripe.

That pipe at the back of the engine is not an oil breather, is it for cooling. An oil breather must, by law, have a filtration system to return the oil to the oil system while allowing air to flow freely. The oil breather will be above the oil tank. It is unlikely the the shaft bearings or gearbox will need a breather, as the return line is always greater than the feed line. That pipe at the back of the engine may contain oil deposits, of course, but this will be from oil leaks from the center and rear bearings - but it is not a pressure equalising oil breather.

As this new technology review from the EUropean Commission says, the oil is leaking from the seals, not the breather. As I said before, jet engines cannot use rubber-type seals, because the temperatures and rpms would destroy them, so they use labyrinth seals. But these are not very secure seals, and jet engines do not use very many of them, because a little oil loss in a jet engine is not a big concern for an engine manufacturer. Unlike the comressor image I showed before, which has four very large labyrinth seals, because oil contamination when pumping industrial gasses can be a real problem. (Note that more concern is taken of industrial gasses, than the health of passengers.)

This EU technology innovation is said to cut oil seal losses by 60%, demonstrating that the greatest losses in aero engines is from the bearing seals and not from any breathers.

An innovative lubrication system for aircraft engines - European Commission


There seems to be a concerted effort by some people on this thread to deliberately distort information to try and demonstrate that jet engine bleed systems have no problems. Perhaps this time and effort would be better spent placing monotoring equipment on 100 aircraft, to see exactly what is coming through the air conditioning systems. It would not be expensive. Just place some simple temporaty filters in the duct for a week, and then test these filters to see what they had collected. $10 k per aircraft tested? Is that too much to ask for?

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Old 20th Apr 2015, 12:43
  #385 (permalink)  
 
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Wow! We've gone from "aerotoxic syndrome" (a medical condition whose existance is highly dubious) to a fantasy disorder called "Selective Reading Disorder (SRD)". I ask again, did you really read the article, or did you make assumptions about the content of the article? And if you read it, how did you come to the conclusion that it remotely supports aerotoxic syndrome, never mind "scientifically proves" it?

Now, on the subject of SRD, you did a fair job describing "what" was done, but you effectively ignored my question. I asked "why" it was done. Why did they build the compressor/bleed air simulator? Why were samples from that simulator "analyzed with gas chromatograph-mass spectrometry". Why were those samples compared against samples taken from cabin air filters that were installed on actual operating airaft?

And given those "whys", what was the result? It's right there in the report. Could the fantasy "SRD" be afflicting the same folks afflicted with the dubious "aerotoxic syndrome"?
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Old 20th Apr 2015, 12:55
  #386 (permalink)  
 
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silvertate

If you read the location of tdracer's whereabouts I'm sure you will get a hint of why he knows just a little bit about airplane design and construction.

The tone in the thread right now seems a bit hostile, folks. Remember that pilots are very carefully checked for all kinds of problems on a much more regular basis than the average population. Since Germanwings, there are voices that want to extend those checks even further. If there was an epidemic problem with aerotoxicity, I am sure the doctors would have found out a long time ago.

Even so, I am still open to the suggestion that a tiny minority of people working in aircrafts might have a sensitivity towards whatever substance you get from oil vapours, and thus react with adverse symptoms.

If you want it to be a world wide conspiracy I would like you to consider the amount of people working with pilot health care. There are waaaay too many that needs to be involved in that conspiracy, it's just not feasible.
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Old 20th Apr 2015, 12:56
  #387 (permalink)  
 
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And here is why MAN places four sets of seals on its axial-centrifugal compressors - they are creating pure oxygen. As you know, or should know, no oil contamination is allowed in such a process.

MAN supplies compressor to record air separation project in South Africa | Hydrocarbon Processing | March 2015

So yes, industrial compressors are made to much higher specification than those pumping air for human consumption. Anyone else thing this is the wrong priority??
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Old 20th Apr 2015, 13:01
  #388 (permalink)  
 
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Snuggles.


Silvertate.... If you read the location of tdracer's whereabouts I'm sure you will get a hint of why he knows just a little bit about airplane design and construction.

Quote: "If you read the location of tdtracer's whereabouts, I'm sure you will get a hint of why he would want to cover up the contamination of aircraft air conditioning systems."

There, fixed that for you.........


there was an epidemic problem with aerotoxicity, I am sure the doctors would have found out a long time ago.
What pilot is going to tell their medic they have lost their mind, and lose their career, house, wife, and kids? Do get real. Besides, when I complained about headaches, and enquired about working at high altitude every day, I was told I was a malingerer.
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Old 20th Apr 2015, 13:03
  #389 (permalink)  
 
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I shall tell Professor About-Donia that the tests he has done on me, and hundreds of other airline crew, have been a waste of time, because some industry apologist says so.
First, I am not (nor ever have been) employed by the industry.
Second, feel free to tell him. He'll tell you that you missed the point of what I said.
Have you actually checked this guys credentials?
Yes.
You must be aware of the denial for years of Gulf War Syndrome. This is the guy who uncovered that problem.
Not relevant.
I think I am justified in believing him. And when another professor tells me that my physical symptoms "can only be down to nerve damage", then I believe him.
Neither of which prove anything with respect to contaminated cabin air.
And the tests done a very "scientific".
I think you misunderstand scientific. It's a system for using measured data to construct a representation of how the world works. It's not a system for taking the laboratory measurements themselves. The tests you had done can be used as an input to "science" but they are not "science" by themselves.
I have also seen a massive amount of evidence which confirms that Organophosphates are getting into aircraft cabins, a lot of which is to be submitted to the courts so I am not able to publish it.
Did you even read what I wrote?
I never, at any point, said that these things were not in cabin air.

(edit) Also, please remember that just because someone isn't jumping onto the Aerotoxic bandwagon does not mean they are denying there could be a problem. Cabin air could be causing health problems, I simply don't know. Neither (based on peer-reviewed literature) does anyone else. Scientific analysis is a slow process. you seem to want all the answers right now but that is simply not possible. So far everything points to the problem being - if it exists at all - very limited in the number of people it affects but there is not enough evidence to say for sure. There are ongoing studies and those will provide more evidence. Until then: Tough luck.
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Old 20th Apr 2015, 13:20
  #390 (permalink)  
 
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silvertate

Please. Bleed air has been used for cabin pressure since the jet babies fumbled around in the skies. Do you really believe there was a massive conspiracy, including all and every pilot medical examiner, XAA, workplace health and security agency, pilot union and all of their relatives, since the day of the Comet?

This conspiracy need to include hundreds of thousands of people working in the business and especially those who deal with health issues. Now, we also know that the engines of yore were not as reliable as the engines now produced, so the instances of aerotoxicity would be much higher then. Do you sincerely believe that those hundreds of thousands of people wouldn't have recognised the problem by... a long time ago?

Besides. Chicklets pointed out that even the name of this syndrome is not very helpful. What would the diagnostic criteria be for "aerotoxic syndrome" in your opinion?
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Old 20th Apr 2015, 13:30
  #391 (permalink)  
 
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I ask again, did you really read the article, or did you make assumptions about the content of the article? And if you read it, how did you come to the conclusion that it remotely supports aerotoxic syndrome, never mind "scientifically proves" it?
Which article? What comment number?
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Old 20th Apr 2015, 13:53
  #392 (permalink)  
 
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Silvertate, despite your bluster you don't seem to know much the inner workings of a jet engine's lubrication system.

As tdracer said, the bearing sumps are pressurised by bleed air and vented to the atmosphere, either via the accessory gearbox or via the shaft to the tailcone. This, together with the breather, is the main path of oil loss.

Here is what you own link says:

"Inevitably however, some lubricant always escapes, for example through vent lines or other parts of the oil circulation system."
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Old 20th Apr 2015, 13:57
  #393 (permalink)  
 
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Snuggles

Please. Bleed air has been used for cabin pressure since the jet babies fumbled around in the skies. Do you really believe there was a massive conspiracy, including all and every pilot medical examiner, XAA, workplace health and security agency, pilot union and all of their relatives, since the day of the Comet?

It does not need to be a conspiracy, Snugs. There are many reasons why this problem is only being raised now.

    There may be other points that can be added to this list.

    As to 'conspiracies', yes, they can develop without direct control. The diagnosis of stomach ulcers was a classic case. Nobody wanting to go against the concensus of opinion in the medical profession meant that doctors wrongly diagnosed ulcers for 50 years or more. Likewise the many doctors in the 40s and 50s who went on record to say that smoking was good for you. Or the recent case where all the thinking on saturated and unsaturated fats has been overturned, and now it seems that butter is better for you than margerine. Yes, the medics do get things wrong sometimes, and it takes a real effort to turn the medical supertanker around once they have made a mistake and it gets into the literature.

    But 'conspiracy' is the wrong terminology here. A doctor who says that you should reduce your stress and spicy foods, is not a part if some grand conspiracy to make people with stomach ulcers suffer. He is just going on the data he has at the time, and cannot afford the time and trouble to set up his own analysis. Same with any possible aerotoxicity. If it is only 2 or 3 % of pilots being effected, who is going to worry? Much easier to pension the guy off -- except for the fact that there are no pensions any more, and so the unemployed pilots are now making a fuss. Do you think any of these guys would be making such a fuss, if they were given 50k a year and told to do some gardening?

    Last edited by silvertate; 20th Apr 2015 at 17:16.
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    Old 20th Apr 2015, 14:05
      #394 (permalink)  
     
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    Thanks, silvertate.

    That was an interesting list of factors. As I said before: there MAY be SOME persons that have some kind of sensitivity to whatever "aerotoxic syndrome" is and therefore may react easier and/or earlier to whatever comes through the cabin.

    But please. What would you include in the diagnose for this syndrome? Aerotoxicity just says that the air is toxic. That can very well be the case in your own garage or re-decorating your bedroom.

    In some cities the air is so polluted that elderly people die earlier. Aerotoxic syndrome?
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    Old 20th Apr 2015, 14:10
      #395 (permalink)  
     
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    Well actually the temperature of a jet engine is seen by the oil, because the blade disks are attached to the shaft and the shaft is attached to the bearings. And most jet turbines have bearings very close to the hot section. So there is a direct heat transfer route from the blade to the bearing - or are you trying to tell me that the blades are not attached to the bearings?!! Whereas an electric compressor has no hot section whatsoever.
    Yes, certainly there is a conductive path from the combustion section to the bearings. That is true of any engine. My point is that the oil is not directly exposed to the combustor enviroment. The oil does pick up lots of heat from the bearings and other pil paths near the combustor section, but those bearings are not operating at anywhere near the temperature of the combustor. Indeed, the oil acts as a coolant for those bearings to draw that heat away and release it in the oil cooler. But that does not even approximately mean that the oil is exposed to the temperatures present in the combustion section. There is a VAST difference between "heat" and "temperature".

    And regards the bearing complexity, you misunderstood my comment. A simple axial-centrifugal electric compressor, similar to the one shown, does not even need any bearings where the compressor is located.
    Let's take your word for it that such a compressor " does not even need any bearings where the compressor is located." The point is "the one shown" (by you) has such bearings. And FYI, the one used in the 787 also has such bearings.

    And yes, they work in many hazardous industrial sites, that are hot, cold, and may even be pumping noxious gasses. And no, they do not use aviation oils as a lubricant.
    Hmmm. How many "work in" an environment that goes go from +120 deg F to -60 deg F in a matter of minutes? And then may go from -60 deg F back to +120 deg F in even fewer minutes? And repeat that hot/cold/hot cycle multiple times per day? None you say?

    And how many operate in an environment that goes from sea level ambient pressure to 38,000 ft (or higher) ambient pressure in a matter of minutes, and then back to sea level in a matter of minutes? None you say?

    And how many operate in an enviroment where they may be exposed to -1G to +3G in fraction of a second? Perhaps repeatedly. And must be designed to handle even higher negative and positive G loads? None you say?

    Perhaps comparing a ground based HVAC air compressor to an aircraft cabin air compressor is rather pointless?

    And these electric compressor systems are indeed much safer than aviation compressor bleed systems.
    "are indeed much safer?" Really? Based on what standards? And what studies? Or even what definition of "safer"? You made a bold claim. How did you define your terms and what did you base you conclusion on?

    They have been supplying offices for decades, with no fumes, no smells, no blue smoke, and no office sickness (apart from bug contamination, which is still a problem in all air conditioning units)
    Really? No one has ever gotten sick in a modern office building? There is no such thing as "sick building syndrome" and the EPA does not now nor ever has recognized nor addressed the term "sick building syndrome"? I just made that up, huh? And the World Health Organizatoin has NEVER estimated that "up to 30% of new and remodeled buildings worldwide may be the subject of excessive complaints related to indoor air quality." No of course not. I just made up that quote, didn't I?

    And indoor office air is completely free of air contaminants (other than of course "bug contamination".) And you can produce studies that have shown that the typical indoor office environment is significantly "safer" or "better" than the typical aircraft cabin environment? And you have access to studies that have shown that office environments are all CERTAINLY free of all organophosphates. Really?
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    Old 20th Apr 2015, 14:10
      #396 (permalink)  
     
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    As tdracer said, the bearing sumps are pressurised by bleed air and vented to the atmosphere, either via the accessory gearbox or via the shaft to the tailcone. This, together with the breather, is the main path of oil loss.
    Err, you are not an engineer, are you.

    You never pressurise a crankcase, gearbox or bearing sump, because that will only induce more oil loss through the seals. Most (all?) car crankcases, for instance, are held under negative pressure to prevent oil leakage. You will have to give me chapter and verse from a manual, if you want us to believe that bearing sumps are pressurised with bleed air, otherwise I am calling bollo on that one.

    Besides, if new bearing seals on jet engines can reduce oil losses by 60% it is axiomatic that most of the oil loss is through the seals, and not via the breather. You do understand what axiomatic is, I presume?

    Last edited by silvertate; 20th Apr 2015 at 14:23.
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    Old 20th Apr 2015, 14:18
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    But while there is the possibility (and some of us know it's more than a possibility)....
    Aaahh yes "some of us know". Well "some know" the Apollo landings were a hoax and "some know" that immunizations cause autism, and "some know" that Elvis is still alive. In each of those cases the "some" are completely wrong. Which is pretty typical of such things.
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    Old 20th Apr 2015, 14:22
      #398 (permalink)  
     
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    KenV

    You seem to be swinging wildly here, Ken.

    Nobody said that aero oil was exposed to 1,000oc temps of the turbine. Only the stupid would think such a thing. But the point is, which you denied, is that aero oils have to cope with very high temperatures, especially as they are being used for bearing cooling, as you yourself admit. While the oil in an electric compressor does not - and so much simpler oils can be used in comparison to the hazardous aero oils.

    As to the temperatures that electric compressors have to deal with, how do you think that cryo-gasses are pumped? How do you think that 400oc petro chemical gasses and fluids are pumped? Do get real, Ken, electric pumps have been used in very hazardous environments long before jet aircraft were invented.

    As to 'sick building' syndrome, well, you are just being silly here. Sick building syndrome has always been linked to contamination in the air conditioning units (as I said) and not contamination by the compressors.
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    Old 20th Apr 2015, 14:23
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    There has been tons of tit for tat about the oil useage/leakage rates of modern turbine engines. Absent in that discussion is any indication of a leak path that leads to the inlet of the compression section of such engines. And absent such a leak path, the entire discussion is both meaningless and pointless in this context.
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    Old 20th Apr 2015, 14:26
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    Err, you are not an engineer, are you.

    You never pressurise a crankcase, gearbox or bearing sump, because that will only induce more oil loss through the seals. Most (all?) car crankcases, for instance, are held under negative pressure to prevent oil leakage. You will have to give me chapter and verse from a manual, if you want us to believe that bearing sumps are pressurised with bleed air, otherwise I am calling bollo on that one.
    Oh dear, we are getting picky and deflecting from the basis of this thread (is is it or isn't it )

    The bearing sump pressure varies with the pressure outside the sump leaking through the seals. How it all works might be interesting to some, but the fact remains that oil leaks and degrades into fumes in a hot environment. How these fumes make their way into the cabin and how much and how bad the effect is worth discussing.

    Of course I fell asleep more than a month ago when nothing new was said.
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