FAA approves Boeing plan to fix 787 Dreamliners

Discussion in 'General Discussion | Travel' started by NYCUA1K, Mar 12, 2013.  |  Print Topic

  1. NYCUA1K

    NYCUA1K Gold Member

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    Passengers won't be allowed back on Dreamliners until the FAA is assured the new battery system works.

    WASHINGTON -- The Federal Aviation Administration approved Boeing's certification plan for the 787 Dreamliner's lithium-ion battery system Tuesday and gave the company the go-ahead to test it in the air.
    Boeing's plans call for redesigning the eight-cell batteries to minimize the risk of a short-circuit, which caused a fire in a Dreamliner parked in Boston on Jan. 7.

    The FAA approved limited test flights for two aircraft, which will have redesigned batteries and enclosures. Testing will cover each plane's two batteries and other systems.
    "This comprehensive series of tests will show us whether the proposed battery improvements will work as designed," Transportation Secretary Ray LaHood said. "We won't allow the plane to return to service unless we're satisfied that the new design ensures the safety of the aircraft and its passengers."

    READ MORE...
     
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  2. Flying Machine

    Flying Machine Silver Member

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    I am hoping that they get a fix for this aircraft soon. Sounds to me like they are formulating a plan. I was soo waiting to fly on it. Missed my planned flight due to the issue and cant wait. For those whom did fly, did you like the experience? Thanks and Safe Travels
     
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  3. NYCUA1K

    NYCUA1K Gold Member

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    With flights already reserved and upgraded to BF to do LAX->PVG and NRT->SFO on this bird, I am with you in hoping that this means that a fix is in sight...by the end of June! :)
     
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  4. anabolism
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    anabolism Gold Member

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    I flew NRT-BOS last spring just to be on the 787. It's a terrific plane -- I felt great after 14-15 hours in the air. I didn't have that usual "cloudy brain" effect. I assume it's because of the higher oxygen (due to higher air pressure) and humidity.
     
  5. jbcarioca
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    jbcarioca Gold Member

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    I want to do that too!
     
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  6. zphelj

    zphelj Gold Member

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    Me too. I'm going to go out of my way to give it a try when they are back in the air.
     
  7. Seacarl
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    Seacarl Gold Member

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    I'm not comfortable that they haven't be able to determine what caused the battery ignition. Had it been a battery manufacturing flaw, I think they would have found other batteries with the flaw. That makes me believe it is likely an intermittent problem in the charging system or some other part of the electrical system, and that the problem will recur. It's great that they have improved the thermal separation of the cells and the containment of fire (things they should have done in the initial design). But until they are able to reproduce the problem that cause ignition and correct it, I'm less likely to fly the aircraft. At a minimum it's got a greater likelihood to need to divert. And I don't know what other systems will provide power in the event that the main battery fails.
     
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  8. HaveMilesWillTravel
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    HaveMilesWillTravel Gold Member

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    I don't know either, but I always assumed the engines would provide the power when they are running. But you know what they say about assuming stuff.

    Has anyone asked Boeing why they didn't design the batteries with those extra separations and containments in the first place?
     
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  9. NYCUA1K

    NYCUA1K Gold Member

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    Boeing has some of the best engineers on the planet, so, therefore, I am quite confident that this is not a one-track thing. On one hand, they must be trying to eliminate the problem so that the bird can take to the skies again without further delays, for many obvious reasons. On the other, there must be a group that has been tasked with trying to find the source or cause of the battery problem. We hear more about the former because of its implications for the reputation and bottom line of Boeing and its customers, who have invested money and prestige in the 787-8, and very little about the latter because it is better to do as little taking about it as possible since the outcome is not known, and then to surprise the world when the culprit has been quietly identified and isolated. However, the two tracks are not mutually exclusive. Eliminating the problem even without knowing what caused it is an excellent way to dramatically decrease the number of possible causes. From there, it may just be a matter of comparing the system with and without each component of the "fix" until it is understood why the fix works, which would also likely point to the culprit.
     
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  10. autolycus

    autolycus Gold Member

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    No need to assume since Boeing has, thankfully, told us that you are exactly correct. See this page and the quoted text below.

     
  11. Seacarl
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    Seacarl Gold Member

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    My understanding is that the main battery is designed to be part of the system even when the engines are providing power - sort of a surge protector as well as perhaps providing peak power demands. Because in almost all normal operations beyond starting the engines, the engines are providing power. So I don't know what happens if the battery fails. I assume that there is some backup, but we don't really know. The JL Boston fire was on the ground, and in the NH issue the battery didn't fail before the plane was on the ground.
     
  12. Seacarl
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    Seacarl Gold Member

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    Boeing's best engineers agreed on a flawed battery design, and have designed an electrical system that has caused battery fires without being able to reproduce the problem.

    Of course they are trying their best. Does that mean we should have blind faith?

    They have not eliminated the problem. They don't even know what caused the problem. What they have done is contained the problem if it occurs.

    I'm not saying I would refuse to fly on the 787, but I'm wary and I'd like to see the aircraft get a million hours of service, unless they can reproduce the ignition scenario.
     
  13. autolycus

    autolycus Gold Member

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    I agree with this general sentiment... the road to hell and all that....

    Sort of. It is possible to eliminate a problem without knowing with certainty that it's the problem. If they identify 10 possible sources--it's actually a lot more than that, according to their latest releases--and eliminate all of those possible sources or at least eliminate the possibility that any of the sources can cause a problem, then they've eliminated the problem without knowing with any certainly what the problem was.
     
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  14. jbcarioca
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    jbcarioca Gold Member

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    Actually they didn't, that is part of the problem. They just accepted their suppliers choices without even an integrated test.
    Of course not. once bitten, twice shy. Further we have Boeing still adamant that there never was a serious problem. Not inspiring confidence. However...
    when you look over the solution in detail and read it all:
    http://www.aviationweek.com/Article.aspx?id=/article-xml/awx_03_14_2013_p0-559485.xml
    or Boeings own site, as well as the other threads here, it's looking very much as though this set of solutions will fly.
    They've eliminated all weight advantage and reduced battery capacity both by charging and discharging limits as well as charging speed limits, so it's hard to see what they see as an advantage now otehr than sheer stubbornness. Still, early indiocations are that they've licked the specific potential causes of the events.
     
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  15. autolycus

    autolycus Gold Member

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    It's a short-term solution. They've given up some of the advantages to Li-ion, but there are certainly still some benefits to it over Ni-Cad. I can almost guarantee they are already working on a better long-term solution to the battery packs. As they get more data from this fix, they'll be able to better understand the safe limits they can push for. My guess is that the current caps on charging and discharging are only temporary and will be adjusted later based on what they learn from additional hours of usage. Of course, if I were them, I'd be really tempted to start looking for a second battery supplier.
     
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  16. jbcarioca
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    jbcarioca Gold Member

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    They claim this is permanent but I'm with you!
     
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  17. autolycus

    autolycus Gold Member

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    It's permanent right up until they submit a certification request for a new design that eliminates all the problems without as many performance or weight sacrifices! :) I mean, we are talking about the future of airframes that will be around for decades, aren't we?
     
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  18. NYCUA1K

    NYCUA1K Gold Member

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    I am not even sure how to respond to something like this, which implicitly discounts the fact that even the smartest people can make mistakes. I am sure that if we here can think of potential issues after the fact, Boeing's engineers must have thought of them too, and more thoroughly... There was a design flaw and there is a lot more to be gained by trying to resolve the issue than to engage in Monday morning-quarterbacking...

    I do not know how you can be sure that "they have not eliminated the problem", when a potential solution has just been approved for testing this very week. It might be better to withhold judgement until after the testing has been completed and the results are made public. The notion that a problem cannot be eliminated without knowing the cause begs the question: how do you know?
     
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  19. anabolism
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    anabolism Gold Member

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    There is value in understanding the root cause of a problem, and more importantly, the process flaw that allowed the problem. Saying it's all in the past is not good. E.g., if the core problem is the outsourced design, it's better to realize this.
     
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  20. jbcarioca
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    jbcarioca Gold Member

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    Clearly that is true. There is an unmistakable difference between "Monday morning quarterbacking" and "root cause analysis" although they may often be confused. The NTSB exists primarily to allow learning from past mistakes. For that reason it has no enforcement authority. The FAA does need to understand what caused the problems in order to properly have a fix. So does Boeing. The very design Boeing is proposing, "kitchen sink" approach, is not optimal as everyone knows, whether it works or not. An optimal solution requires understanding root cause.
     
  21. milchap
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    milchap Gold Member

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    Here is an analogy taken from the world of oncology.

    The disease can be arrested by various fixes (radiology, chemotherapy) and the patient is said to be in remission not cured. Researchers all over the globe are working hard to discover the rooot causes of various forms of cancer.

    Applying the analogy to Boeing, I do hope that the fix is not only a remission for the battery system. I would feel much more comfortable if research found the root cause of those failures.
     
  22. anabolism
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    anabolism Gold Member

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    Here is an illustration:

    [​IMG]
     
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  23. jbcarioca
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    jbcarioca Gold Member

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    We have that posted in each thread now, I think. Among the open questions are:

    The process for cell construction. Other manufacturers speak of 60% pass rates while Yousa reported 90%. Presumably that is addressed.
    The process for physically ensuring that layers do not fold or move incorrectly within a cell. There's lots of comment about that on pprune, among other places.
    Measurement of individual cell performance. The schematic here shows nothing changed, but some text suggests it will. If so, how?
    How to protect against uneven activity within individual cells.

    And myriad other questions. From all I have read it seems likely that this will work well enough to fly.
    Most of the authorities on the subject I have read seem to think there will be a new solution forthcoming fairly soon, even though Boeing calls this one "permanent". It hardly is likely to be so when the entire setup now weighs as much as ni-cads.
     
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  24. Seacarl
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    Seacarl Gold Member

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    There are two statements in Boeing's Japan presentation which are discordant:

    One is slide 4, which it titled "Batteries Perform Limited Functions". The summary at the end says "Primarily Ground Operations, Not Flight Critical". It's discordant to say that the functions are limited and not flight critical, and then to put emphasis on the improved functionality of Li Ion technology, and to design the always-in-use-while-flying charging system. I suspect the battery system is in fact flight-critical, because otherwise one immediate solution would have been to stop charging the batteries in-flight and recharge them on the ground instead. I believe that the battery is always live in flight operation.

    The second is slide 8, which states "The only possible cause for thermal runaway at an airplane level is overcharging" and "Following detailed review no evidence of overcharging was found in either event". Either the first statement is false, or if it is true, then overcharging must have occurred even if they could not find evidence.

    These comments are in reference to the PDF here http://www.nycaviation.com/newspage.../Boeing-787-solution-presentation-English.pdf
     
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  25. jbcarioca
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    jbcarioca Gold Member

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    There are actually more. Rather than making my weak attempt to describe them I suggest reading here:
    http://www.pprune.org/tech-log/505695-787-batteries-chargers.html
    This thread has much discussion fro electrical engineers cognizant of battery chemistry, including li-ion and the specific B787 designs.

    in any event the APU battery, it seems, could be inoperative because the Minimum Equipment List (MEL) apparently allows operation of the B787 without an operational APU and the rear battery bank serves as the APU battery. The main battery most definitely is flight critical according to everything I have seen. Boeing is disingenuous, at best, in making an assertion that the batteries are unimportant. I think of stronger words, but I'm trying to be restrained.

    Slide 8 is heading to and through deception, IMHO. Boeing seems to have decided that overcharging was "...the only possible cause..." when it is transparently obvious that there are other causes. In any event there is not adequate information on which to judge whether or not overcharging did take place because they only measured charging at the aggregate level of a battery bank, not individual cell or position within a cell. therefore they only measured gross averages and nothing else.

    Several comments from Japan make it clear that Boeing has not been possessed of integrity ( http://www.merriam-webster.com/dictionary/integrity) because superficiality does not make the grade, nor does presenting only points that supports ones own position.

    In the linked thread is much more information to give anybody serious pause. Example:

    The battery charging mechanisms were only tested using phantom loads rather than an actual GS Yuasa B787 battery. Why? They did begin such testing but it caused a battery fire, so they stopped such testing ion the interests of safety.

    It's impossible to make such stuff up, I think.

    We should hope the FAA ensures they are not sold a false solution this time. It is hard to actually believe that all we are being shown is necessarily what is being delivered. Test and confirm.
     
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