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Another 787 Fire this time at LHR

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  • #46
    The AAIB have recommended turning off the ELT until appropriate airworthiness has been completed.

    Source: AAIB Bulletin (PDF file)

    They seem to be concerned because there is no fire detection system in that area of the aircraft.

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    • #47
      Originally posted by ClarkF1 View Post
      The AAIB have recommended turning off the ELT until appropriate airworthiness has been completed.

      Source: AAIB Bulletin (PDF file)

      They seem to be concerned because there is no fire detection system in that area of the aircraft.
      I'm confused about this. The ELT normally turned off anyway. The actual recommendation instructs operators to 'make inert' the ELT. I'm thinking—I'm hoping—that this means removal of the battery, because the battery was the only source of power that could have caused this fire (ground power was disconnected and the aircraft was secured). But I can only guess as to what 'make inert' means. From the description of the smoke, this would have been disastrous in the air, and halon extinguishers were ineffective in putting the fire out.

      At any rate, if a 787 catches fire in flight and disappears from radar anytime soon, now we won't have an ELT to find it.

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      • #48
        Originally posted by Evan View Post
        I'm confused about this. The ELT normally turned off anyway. The actual recommendation instructs operators to 'make inert' the ELT. I'm thinking—I'm hoping—that this means removal of the battery, because the battery was the only source of power that could have caused this fire (ground power was disconnected and the aircraft was secured). But I can only guess as to what 'make inert' means. From the description of the smoke, this would have been disastrous in the air, and halon extinguishers were ineffective in putting the fire out.

        At any rate, if a 787 catches fire in flight and disappears from radar anytime soon, now we won't have an ELT to find it.
        Yeah, I read about this in the LA Times, and I also question the safety of doing this.

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        • #49
          From the July 16 AIAA Newsletter:

          Incident A Test Case For Cost, Ease Of Extensive Composite Repairs. According to Reuters (7/16, Scott, Hepher), the fire is a test of Boeing’s use of composite materials because it will show how easily the damage can be repaired. The article notes this is the first time extensive composite repairs have been needed on a commercial plane so this will be a benchmark for the costs airlines could face.


          Also there are 6,000 ELTs of this type on a variety of aircraft http://www.aaib.gov.uk/cms_resources...3%20ET-AOP.pdf

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          • #50
            Originally posted by Evan View Post
            I'm confused about this. The ELT normally turned off anyway. The actual recommendation instructs operators to 'make inert' the ELT. I'm thinking—I'm hoping—that this means removal of the battery, because the battery was the only source of power that could have caused this fire (ground power was disconnected and the aircraft was secured). But I can only guess as to what 'make inert' means. From the description of the smoke, this would have been disastrous in the air, and halon extinguishers were ineffective in putting the fire out.

            At any rate, if a 787 catches fire in flight and disappears from radar anytime soon, now we won't have an ELT to find it.
            Too much on stake to let a 787 disappear, things can be found without a beacon.
            "The real CEO of the 787 project is named Potemkin"

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            • #51
              Originally posted by Alessandro View Post
              Too much on stake to let a 787 disappear, things can be found without a beacon.
              AF447 was found - eventually - with no help from the ELT.

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              • #52
                They (AAIB) are NOT saying this was the fault - the ELT !
                It is VERY interesting that the unbilical was connected at the time, but 'unpowered' ....
                Ground potential differential issues are a possibility.

                Composite designs are problematic in circuit grounding issues.

                Time will tell. I personally believe it was highly unlikely that the ELT was to blame. but.. ? we shall see, at least the best in the world (AAIB) are on the case. So, confidence is high as to a resolution. If I had shares in Boeing, I think I might be selling - quickly....

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                • #53
                  Originally posted by HalcyonDays View Post
                  AF447 was found - eventually - with no help from the ELT.
                  Good point! As far as looking at the composite design; I honestly don't see the point. I mean, even if composites are worse in fires and harder to repair, it's not like Boeing's going to re-engineer the 787 with less composites-that would cost a TON of money (I would think), and probably isn't even on the table for Boeing. Or Airbus, with the A350, or any other aircraft manufacturer that makes extensive use of composite materials in their airplanes.

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                  • #54
                    Originally posted by UALdave View Post
                    Good point! As far as looking at the composite design; I honestly don't see the point. I mean, evn if composites are worse in fires and harder to repair, it's not like Boeing's going to re-engineer the 787 with less composites-that would cost a TON of money (I would think), and probably isn't even on the table for Boeing. Or Airbus, with the A350, or any other aircraft manufacturer that makes extensive use of composite materials in their airplanes.
                    Question is if the ELT needs to be grounded, harder to ground something to carbonfiber than metal I presume?
                    "The real CEO of the 787 project is named Potemkin"

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                    • #55
                      I haven't had the chance to check the latest, but here is an interesting possibility from earlier today: The 787 is different in several ways, one being the higher cabin humidity. There was a suggestion that maybe that interacts with the wiring and that maybe its insulation needs to be revisited.

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                      • #56
                        We have now like 20 or 30 years of high performance civilian twin jets with composite fuselages certified under the same FAR 25, and I haven't heard of any strange trend on them due to the extensive use of composites, even when they were fitted with ELTs.

                        Design problems? Maybe.
                        Intrinsic problems with the nature of fiber-reinforced plastics? Forget it.

                        --- 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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                        • #57
                          Originally posted by HalcyonDays View Post
                          AF447 was found - eventually - with no help from the ELT.
                          There was a previous case where it took 14 years. Is luck a major factor in finding the AF447 black boxes? Or is all the other technology surrounding flight just evolving and improving over time, too.

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                          • #58
                            Originally posted by Gabriel View Post
                            We have now like 20 or 30 years of high performance civilian twin jets with composite fuselages certified under the same FAR 25, and I haven't heard of any strange trend on them due to the extensive use of composites, even when they were fitted with ELTs.

                            Design problems? Maybe.
                            Intrinsic problems with the nature of fiber-reinforced plastics? Forget it.
                            I fully agree.
                            One problem when using composites has always been electrical circuit design. (Not at all an issue of the composite itself, purely an electrical design issue.)
                            It is also very interesting to note that the AAIB has NOT recommended making inert (removing batteries and connections) of the ELT in any other design apart from the 787...... why ? ... imho, simply because they do not think it IS the cause of the issue, the cause of the fire, possibly, but not the cause of the issue.. in other words, heat from wiring etc outside the elt caused a battery chemical breakdown.
                            Heat in wiring is caused by current flow and resistance, poor grounding can lead to high resistance. A very interesting case that I will be pleased to see an outcome to, and NOT a botch solution as in 'put in in a box' as per the batteries.
                            I hope to whatever god one may believe in that one of these designs does not fall from the sky, they are playing with fire, literally..

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                            • #59
                              Here's the latest article on this:

                              http://www.nytimes.com/2013/07/20/bu...wire.html?_r=0

                              An interesting quote from this article: "But battery experts said that barring a flaw in the battery's construction, the transmitter is sealed so tightly that neither moisture nor heat was likely to cause a short circuit."

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                              • #60
                                Next Monday's Aviation Week has a two page story on this failure. Highlights are:

                                The fire did not burn through the skin but was hot enough to char the exterior painted surface.

                                The composite is more resistant to fire than aluminum.

                                Boeing plans to repair the aircraft (patch or new tail section) but write off is still possible. Boeing has developed repair procedures but did not expect to use them so soon.

                                The 787 has two ELTs (one fed and one aft) plus more in life rafts.

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