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  • Toxic fumes in cabins and cockpits

    Recent events here in Germany have prompted me to open this thread. The German Federal Office for Air Accident Investigation (Bundesstelle für Flugunfalluntersuchung - BFU) has published an interim report (so far only available in German: http://www.bfu-web.de/cln_030/nn_223...tml?__nnn=true) about an incident involving a Germanwings Airbus A319-132 on approach to Cologne airport (CGN/EDDK). Toxic fumes entered the cockpit and nearly incapacitated the flightcrew. However, they managed to land the aircraft without any damage. The incident is currently a hot topic in the German press.

    I would like to hear any thoughts and ideas about the topic of fumes in the cabin and cockpit in general. Any theories to the causes and to how to address the problem? Which aircraft and/or engine types are affected?

  • #2
    the whole concept of bleed air is horribly mis-conceived, just run an external compressor as the 787 does
    moving quickly in air

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    • #3
      Originally posted by Peter Kesternich View Post
      Toxic fumes entered the cockpit and nearly incapacitated the flightcrew. However, they barely managed to miraculosuly land the aircraft luckily without any damage with the help of God.
      Fixed, but really, they were like drunk and fainting, with O2 levels in blood well below 80% (normal: above 95%)

      For those who (like me) don't speack german, good information in English in Avherlad:
      Aviation Herald - News, Incidents and Accidents in Aviation

      --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
      --- Defend what you say with arguments, not by imposing your credentials ---

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      • #4
        Well, I have to say this is pretty frightening. There has to be a reason this happened and I'm amazed it isn't being thoroughly investigated. As to solutions? I don't play at that level but I guess you could have a rule that one of the pilots is always on O2, but if there is a fire I'd hate to have my face blown off.

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        • #5
          Originally posted by Peter Kesternich View Post

          I would like to hear any thoughts and ideas about the topic of fumes in the cabin and cockpit in general. Any theories to the causes and to how to address the problem? Which aircraft and/or engine types are affected?
          Fumes in the cabin can come from different sources from componets in the cabin/fuselage(Air conditioning, galley equipment, avionics, etc), Engine systems (oil, hydraulic) and sometimes from outside sources like de-icing fluid or ash from a volcano. I really think there is no way to prevent all smoke events but there are some that can be prevented.

          As for emergency procedures for flight crew, oxygen masks must be worn at the first sight/smell of smoke and emergency procedures must be executed in a timely fashion. It all depends on the airline's emergency procedures, but with this Germanwings incindent, I was wondering how long from the time the crew noticed the smell to when they donned the oxygen masks(It is almost similar to cabin pressurization issues and how it affects the body-time is a factor).

          You can check avherald and see other smoke events to see what I am talking about.

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          • #6
            What I find amazing about this incident is how quickly the O2 in the blood went down so much.

            I very much doubt that the air in the cockpit, other than contaminated by some gas and smoke, was so much depleted of O2.

            The air being "pumped" all the time into the cockpit and it is the same air that goes into the cabin, and in the cabin nobody noted anything, so I don't think that the exterior air sucked by the engines or the bleed system or air conditioning are the culprit here, or it would have affected both the cabin and the cockpit.

            On the other hand, for a problem in the cabin to "consume" a lot of O2 from the air it would take a huge chemical reaction, and an exothermic one, since oxidation releases heat. That means, a big fire. But apparently there was nothing of that.

            Finally, if lack of O2 was the problem, the masks, that are airtight and supply 100% O2, would have solved the problem quickly, but the pilots felt bad even after several minutes (or even hours) after deplaning and being treated (probably with supplementary O2 as part of such treatment).

            My knowledge of medical sciences and physiology are poor at best, so I ask this question to our resident doctors/paramedics. Is it possible that there was enough O2 in the air but the lungs were quickly and persistently affected in some way as to prevent them from "capturing" the available O2. How?

            --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
            --- Defend what you say with arguments, not by imposing your credentials ---

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            • #7
              Originally posted by Gabriel View Post
              of such treatment).

              My knowledge of medical sciences and physiology are poor at best, so I ask this question to our resident doctors/paramedics. Is it possible that there was enough O2 in the air but the lungs were quickly and persistently affected in some way as to prevent them from "capturing" the available O2. How?
              Doesn't carbon monoxide displace the oxygen in the haemoglobin in the bloodstream? Maybe if not CO poisoning then something similar in the cockpit.

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              • #8
                Originally posted by SYDCBRWOD View Post
                Doesn't carbon monoxide displace the oxygen in the haemoglobin in the bloodstream? Maybe if not CO poisoning then something similar in the cockpit.
                And would this condition develop quikly but remain for a long time even when a contamination-free, O2-rich air is being supplied?

                For example in altitude related hypoxia, the condition reverts very quickly as soon as O2 is supplied (if there is not brain damage, of course).

                The same in G-LOC. You can see videos on you-tube with passengers literally passing out during a hig-G maneuver, and becoming "alive and well" again, as if nothing had ever happened, immediatelly when the-high G stops (In this case I understand it: the blood IS full of O2, it's just not reaching the brain. As soon as it does, up you are again)

                --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                --- Defend what you say with arguments, not by imposing your credentials ---

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                • #9
                  oil, fuel, de-icing fluid etc is burned in the engines and releases toxic fumes. a fault in the system sees these fumes enter the aircraft through the bleed air used in the air conditioning. sometimes the cabin and cockpit are fed by different engines. solutions? inspect the systems, check the air for any signs of contamination, design aircraft with external compressors. if its an electrical or galley fire that is obviously a separate issue. in this case the delay in going on oxygen contributed to the severity
                  moving quickly in air

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                  • #10
                    Originally posted by orangehuggy View Post
                    oil, fuel, de-icing fluid etc is burned in the engines and releases toxic fumes. a fault in the system sees these fumes enter the aircraft through the bleed air used in the air conditioning.
                    At what stage is bleed air taken from the engine? I guess at some stage of the compression, well before the combustion chamber.
                    How do combusiton gasses get there flowing upstream agaisnt the pressure gradinet?

                    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                    --- Defend what you say with arguments, not by imposing your credentials ---

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                    • #11
                      The bleed air does indeed come from the compressor - the stage depends on the engine and the thrust setting at the time. The air is bloody hot when it comes out though!

                      The chemicals that have been involved in these incidents in the past are bloody nasty. I know of pilots who have been off work for many months following an inflight exposure... and others who have been completely incapacitated with vomiting and headaches immediately, and have been very sick puppies for a few days. Fortunately that was on the ground.

                      It does sound suspiciously like toxic chemical poisoning to me. Not something like CO2 which, as you suggest, would be rectified quickly by the use of O2.

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                      • #12
                        Originally posted by Gabriel View Post
                        At what stage is bleed air taken from the engine? I guess at some stage of the compression, well before the combustion chamber.
                        How do combusiton gasses get there flowing upstream agaisnt the pressure gradinet?
                        Here's an excerpt from a 737 manual--this is the bleed air description of the CFM-56. If I recall correctly, there are 13 stages in the engine so the bleed air is taken at least 4 stages forward of the combustion chamber:
                        ENGINE BLEED SYSTEM SUPPLY
                        Bleed air is obtained from the 5th and 9th stages of the compressor section of
                        the engine. When 5th low-stage pressure is insufficient, the 9th high-stage
                        valve modulates open to maintain proper pressure. During takeoff, climb, and
                        most cruise conditions, the pressure available from the low-stage port is
                        adequate. The high-stage valve remains closed when 5th stage pressure is
                        adequate
                        .

                        The 757/767 is similar, though they just tell us "Low stage" and "High stage" bleed air. I want to say the old JT8's (727, 737-100/200) used 9th and 13th stage bleed air. Anyway...you get the picture.
                        The "keep my tail out of trouble" disclaimer: Though I work in the airline industry, anything I post on here is my own speculation or opinion. Nothing I post is to be construed as "official" information from any air carrier or any other entity.

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                        • #13
                          Originally posted by Gabriel View Post
                          At what stage is bleed air taken from the engine? I guess at some stage of the compression, well before the combustion chamber.
                          How do combusiton gasses get there flowing upstream agaisnt the pressure gradinet?
                          Not trying to be an ass, but it would be flowing with the pressure gradient. If you have 2 leaks, on in the high pressure turbine stage and one in the low pressure compressor, the combustion gas could flow around the outside of the case and back into the compressor, because that's the way the pressure gradient points.
                          The compressor makes the air flow into high pressure, that's why flow separation is an issue in the compressor, but (usually) not in the turbine

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                          • #14
                            Originally posted by MCM View Post
                            It does sound suspiciously like toxic chemical poisoning to me. Not something like CO2 which, as you suggest, would be rectified quickly by the use of O2.
                            I know wiring has been an issue in the past--I don't remember the exact details, but there was a type of wiring that they discovered would produce toxic fumes if it got hot or burned. Could that be the cause here?

                            I'm wondering if it was a subtle incapacitation that began much earlier and was just noticed prior to landing. They went on oxygen but I'm thinking they had their masks set to "normal" (which mixes O2 with ambient air) instead of "100%". As badly as they were feeling, a better setting would be "Emergency" which provides oxygen at positive pressure and forces it into the lungs. Of course, I'm analyzing this while sitting here in my hotel room with fully-oxygenated blood, not in the heat of battle trying to fly the airplane while not passing out...

                            In the US, flightcrew incapacitation is an NTSB reportable event. If the same thing happened here, the company would be required to report the incident to the National Transportation Safety Board and there would be a full investigation. The airplane would probably be taken off line until they could find the cause. I'm surprised they didn't do a full toxicology screen in the hospital to see what was affecting these guys.

                            One other thing...since the FO seemed to be more seriously affected than the captain, I'm thinking they should have started searching for a cause on his side of the airplane first.
                            The "keep my tail out of trouble" disclaimer: Though I work in the airline industry, anything I post on here is my own speculation or opinion. Nothing I post is to be construed as "official" information from any air carrier or any other entity.

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                            • #15
                              Originally posted by Taliesin View Post
                              Not trying to be an ass, but it would be flowing with the pressure gradient. If you have 2 leaks, on in the high pressure turbine stage and one in the low pressure compressor, the combustion gas could flow around the outside of the case and back into the compressor, because that's the way the pressure gradient points.
                              I see.
                              The compressor makes the air flow into high pressure
                              That's an odd way to put it. I'd rather say that the compressor increases the pressure of the air and then the air flows to a zone of lower pressure (but higher than before the compressor).

                              Saying that in a compressor the air flows into high pressure is like saying so in a bike pump (from the atmosphere to inside the tyre). In fact, you mechanically compress the atmospheric air to a higher pressure than inside the tyre and then it flows from a higher pressure (pump chamber) to a lower pressure (inside the tire).

                              Or than an air conditioner makes the heat flow from a cool zone (room) to a hot zone (exterior). What it does is cool a gas below room temperature to make it absorb heat from the room, then heat it above the exterior temperature to make it release heat outside.[/quote]

                              --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                              --- Defend what you say with arguments, not by imposing your credentials ---

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