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American Capital Agency Corp. Message Board

  • yourbestfriendintheworld yourbestfriendintheworld Apr 19, 2013 7:52 PM Flag

    OT: BA and batteries

    Did I call this or did I call this? This wasn't a drop-in replacement, not in the slightest. They spent 300,000 man-hours redesigning and retesting this thing (figure $50 million with overtime). The manual just for this fix is 500 pages long, and it takes 5 solid days to install it in each existing plane. No word on how much more effort it will take to redo the manufacturing line and work-in-progress; that's a whole nother engineering process itself. Here's the deets on the design change:

    "Boeing's new battery design involved encasing the redesigned power pack in a steel box, packing it with different insulation, heat-resistant material and spacers, adding drainage holes to remove moisture and venting any gases from overheating directly to the atmosphere outside the aircraft."

    That last bit is a riot. They punched a hole in all the structure between the existing mounting location and the _side of the aircraft_ to let it spit fumes into the slipstream. Probably had to beef up some of those walls as well. Now, some of this is no doubt overkill that is done to satisfy the "what ifs" brought up by the regulators during spitballing. When you're behind this 8-ball, it doesn't look good to try to argue them out of things, it's best to allay their imaginary worries by installing the alligator repellent. But it ain't cheap either way.

    Moral of this story: Don't slack on the verification process. Inspect your suppliers (Boeing was touting the cost savings of its parting-out of the design and fabrication to others) and test the hell out of your hazardous components. Because if you leave the inevitable to chance, then when the inevitable happens you will be chained to your desk until it's fixed. Luckily, this only inconvenienced a few passengers and firemen, and made a few rich people poorer. If only we did the same diligence for fertilizer plants as we do for airliners...

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    • Boeing already admitted several years ago that the outsourcing that it did on the 787 was a mistake, one they plan to correct in the future. So I don’t think that future redesigns or new designs will include as much outsourcing. However I doubt that Boeing will ever make its own batteries or fabricate its own piece parts as they are a systems house. But they seem to be willing to do more in house final assembly down to a lower level than they did on the 787, more like they are doing on older designs. And besides, why teach your competitors how to do these kinds of things.

      I'm pretty impressed with the amount of resources that Boeing threw at the battery issue. But what choice did they have? The plane was grounded and this was making customers unhappy. So it appears that they threw an army of engineers at it and got it done ASAP.

      From what I read they basically made it so that the battery can essentially self destruct and no harm will come to the plane. This approach is kind of brute force but then it makes it hard to challenge the solution as not being adequate. My guess is that eventually they will come up with something more elegant.

      The problem is that these lithium batteries are prone to overheating if you don't control them precisely. I suspect that it was a tradeoff between efficiency and safety meaning that they can run the generators more often and rely on the batteries less. However such a solution may not have assuaged the people who wanted to see something more dramatic so they encased it in a fire proof container to prevent a fire even if one never occurs in the future. It was probably over kill but certainly no harm in doing this other than the extra expense of implementing it. At this point getting the 787s back in the air is priority number one.

      CREE is having another good day. I’m researching 3D printers right now but haven’t decided that I like anything yet. DDD, SSYS and XONE are what I have been looking at.

      • 1 Reply to raybans2
      • yourbestfriendintheworld yourbestfriendintheworld Apr 22, 2013 3:40 PM Flag

        i think someone pointed out to them that a lithium battery is essentially a firebomb, if not an explosive device, and they were nuts to have created a system requirement (something about backup power for control or navigation systems) that only a lithium battery could fill without weighing a literal ton. and there's the problem of mechanical stress as the pressure and temperature change in the aircraft. not so noticeable in a rigid package in a small form factor in your pocket, despite sitting on it and leaving it on your dashboard and whatnot, but when packaged in layers in a cubic-foot box, it's amplified greatly. so they created a box for it that will take whatever worst-case scenario a lithium battery can throw at them.

        and it was clearly a showstopper, because if they couldn't get 787 back online, they were going to go belly-up. you don't lose a half-trillion dollar product line in a couple of months following a ten-year design effort and chalk it up to experience. so that's why the focus went on it.

        the question now is, have they done anything to keep the batteries from melting down inside the meltdown containment box? because it can't be cheap to have to swap them out every few flights. cheaper than losing loaded aircraft, but more expensive than crew time.

    • yourbestfriendintheworld yourbestfriendintheworld Apr 21, 2013 12:42 AM Flag

      in reply to myself: "If only we did the same diligence for fertilizer plants as we do for airliners."

      it turns out, we do quite a bit of diligence for fertilizer plants. any plant storing over 400 lbs of AN has to self-report to the feds to be inspected and tracked. for the security of the homeland. see.

      but this plant, just about dead-center in the heart of texas, decided it was above the law. so it was storing 540,000 lbs and not bothering to tell anyone. which creates two problems; 1. nobody was there to tell them that their town's fire department didn't have a chance of stopping an explosion if a fire started; 2. they would probably never notice if terrorists were carting off half a ton at a time and stockpiling it elsewhere, then setting a fire to make sure nobody could verify lossage in an eventual audit.

      100% liability for the plant owners for dozens of lives and hundreds of injuries and homes.

      and hopefully the state of texas gets the federal #$%$-whupping it's been begging for ever since the messkins conned us into taking it.

    • and they whacked every gram of saved weight in the process. just like autos.

    • They fired the guy who suggested more reliability.
      In a business that size, the extra labor is cheap insurance against catastrophe.
      Just think, two more guys on the job in West, TX, would have given them the freedom to run a safe facility and save them 25million dollars. Nitrogen compounds man,....
      they gave their lives for the periodic wake-up call that the industry needs every 12 years.

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