Boeing - Design Issues...

Discussion in 'Rules and Regulations / Flight Safety / Better Pil' started by TXFlyGuy, Apr 11, 2019.

  1. Apr 12, 2019 #21

    BJC

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    One of the side effects of a booming economy. Could be corrected by the owners, and probably will be, once they conclude that the high production rate will continue long enough to justify the additional cost.
    Is that driven by union rules or management rules?
    The safety record for commercial air transport in the USA, as previously noted by others, remains better than traveling in automobiles.


    BJC
     
  2. Apr 12, 2019 #22

    mcrae0104

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    I would love to help, but I quit watching when the star witness said, "Nobody cared about the safety aspect." I don't know about the validity of anything that followed, but it had the fearmongering tone of a Dateline story blowing up pickup trucks (with assistance from model rocket engines) and so I didn't bother to give them my time.
     
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  3. Apr 12, 2019 #23

    12notes

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    It works out to 0.0762mm. I'm not sure if 0.07 or 0.08mm are common tolerances, but I haven't seen either before. 0.05mm I've seen, but it's about 0.002" (.00197).

    EDIT: I goofed and calculated .003" instead of 1/3000th here. 0.003" = 0.0762mm.
    1/3000 of an inch is 0.00847mm.
     
    Last edited: Apr 12, 2019
  4. Apr 12, 2019 #24

    ScaleBirdsPaul

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    I'm pretty sure they mean 3/1000th of an inch or .003. I believe that what they reported may be factually true but I don’t trust that it paints an accurate picture.
     
    Last edited: Apr 12, 2019
  5. Apr 12, 2019 #25

    Himat

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    0,1mm and 0,05mm are common tolerance to see on a drawing. With SI units any step of 1 can and is probably used so 0,07mm or 0,08mm is not strange. 0,075mm is half of a 0,15mm tolerance and that one could be considered common.
     
  6. Apr 12, 2019 #26

    12notes

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    I just realized I had converted .003", 1/3000" is actually 0.00846mm. I corrected my previous post.

    But realistically, I'm pretty sure my original interpretation is correct. 1/3000th of an inch is just plain awkward and I've never heard anyone use fractions in inches like that, just powers of 2 in fractions (and usually no smaller than 1/64") or decimal.
     
  7. Apr 12, 2019 #27

    BBerson

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    3000 thousands is 3".
     
  8. Apr 13, 2019 #28

    TXFlyGuy

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    Yes, the old Firestone / Ford tire controversy. Car & Driver pretty much put that to rest, after they did just what you said...placed a charge in the wheel well, and blew up the tire at highway speed. The Ford Explorer did not flip over. And it was controllable throughout the deceleration.
     
  9. Apr 13, 2019 #29

    mcrae0104

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  10. Apr 13, 2019 #30

    gtae07

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    If it's anything like my employer, probably neither one. It's just a consequence of the hours. Even with a nice shift differential it's often hard to find people for second, third, and weekend shifts; typically all you find are single people, guys with very young children and stay-at-home wives, or old guys whose kids have moved out. It's even worse when you get to engineering; very few engineers are willing to regularly work an off-shift and it's nearly impossible to fill those slots if you're only allowed to hire internally.

    Then again, we don't rotate people on and off of different shifts. You hire in for an off-shift and you typically stay there for a while.

    I'm coming up on two years of weekend shift and I probably have about two more to go before I go back to regular dayshift as my son starts kindergarten.
     
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  11. Apr 13, 2019 #31

    markaeric

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    Sure, but expansion takes time even if it is to happen, though what might happen in the future can't really affect what might happen in the meantime.

    gtae07 elucidated on the reality of the nature. First off, I'd just like to mention that there certainly are some very skilled employees on the off-shifts (these tend to be people who actually want those particular hours), but the proportions are worse compared to the primary shift. Whatever the rules are, they're ones that have been agreed upon by both union and management, assuming it's a union shop, and at least around here the union isn't all powerful. I suspect that if management wanted to throw in some way of incentivizing senior employees to work off shifts, they probably could get it in the contract, but they'd rather just bellyache about the higher proportion of quality issues coming out of those shifts. Now what if you could force them to do it? Well, either they'd jump ship or you'd ruin morale. Not a good way to treat your good employees, is it?

    As for the lowest level managers, most of them give no consideration to someone's ability when assigning them to a task. Job X needs to be assigned to someone? Whoever the next warm body in line is will fill the vacancy. It seems like common sense, but over and over I see people assigned to a task they're ill fitted for, and the foreman doesn't even think twice about it. I wish I had the opportunity to see how our non-union shop operated. I bet it wasn't significantly different.

    No argument here. What I was getting at is luckily airplanes aren't generally built with razor-thin margins, so that common unaccounted for manufacturing/maintenance defects such as material gouges, dents, out of tolerance holes, fastener installations not to spec, mislocated parts, etc - all issues that I imagine most production planes have to varying degrees, doesn't automatically bring a plane down in its lifetime.
     
  12. Apr 13, 2019 #32

    TFF

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    Those ill suited workers in a union shop become shop stewards and do even less. Good foreman will make those bad workers work, the bad foreman hide those workers and over work the good ones. The bad workers knew how much to screw up so they would get put back on checking tire pressure but not enough to get fired. I worked with some professional bad mechanics.
     
  13. Apr 14, 2019 #33

    markaeric

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    I meant more along the lines of some people being tasked with performing functional tests who have no business doing that because they can't troubleshoot worth a sh_t, while some other technically savvy person is tasked with mindlessly installing cabin insulation and baggage panels. A good foreman utilizes his resources effectively. Unfortunately, most foreman are not particularly good.
     
  14. Apr 14, 2019 #34

    BJC

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    A frequent mistake is to select a group leader based on either seniority or technical skills. Neither is an indication of the leadership skills required for the job. Would also note that neither is a disqualifier, and the technical skills are a big plus IFF complemented with the leadership skills.


    BJC
     
    Last edited: Apr 14, 2019
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  15. Apr 14, 2019 #35

    gtae07

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    Well, it wasn't actually me you quoted but agree 100% with your statement.
     
  16. Apr 14, 2019 #36

    BJC

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    Sorry about that. I had started to reply to two quotes, but got distracted and screwed up. I deleted the quote box.


    BJC
     
  17. Apr 15, 2019 at 4:44 AM #37

    bmcj

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    I heard something the other day from a friend who has connections with many 737 pilots. Perhaps someone here can confirm or refute this.

    According to his resources, the MCAS was originally designed with 0.8 degree max stab change to avoid excess overtrim, but that was found insufficient and later changed to a maximum of 2.x degree degree max stab movement (I think he might have said 2.4 degrees). However, after the MCAS stab limit is reached and if the pilots shuts the system off, then back on, the system resets to zero and then allows another 2.4 degree stab movement.

    I’m not one to take heresay as gospel, but at least this one sounds feasible.
     
  18. Apr 15, 2019 at 1:30 PM #38

    TXFlyGuy

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    I only had three career goals...one of them being to never fly the B-737.
     
  19. Apr 17, 2019 at 10:47 PM #39

    SVSUSteve

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    That's absolutely not what happened. It was a fatigue failure, poor oversight, etc. https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243

    It is worth noting that the minority opinion of at least one NTSB member laid part of the blame on Boeing for failures to maintain exercise due caution for aircraft operating in environments where high cycles and increased corrosion risk line up (read as: closely interspersed islands like Hawaii).
     
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  20. Apr 18, 2019 at 2:23 AM #40

    TXFlyGuy

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    You are correct, in the fatigue statement. But the primary contributing factor to the accident was the crews improper manipulation of the manual pressurization controls. In conjunction with the failure of the relief valves to function as designed, causing the ultimate "convertible 737". Due to PC issues, much of this was swept under the rug. Or so I'm told.

    Perhaps this was just made up? Don't know. But I could not find any info on MEL's the plane might have had at the time of the flight.

    If the auto pressurization system was fully functional at the time of the flight, then the above is just another bad rumor. Started by a male pilot, no doubt.
     

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