Boeing - Design Issues...

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

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  1. Apr 11, 2019 #1

    TXFlyGuy

    TXFlyGuy

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    Last edited: Apr 11, 2019
  2. Apr 11, 2019 #2

    Vigilant1

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    Al Jazeera--noted.
     
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  3. Apr 11, 2019 #3

    TXFlyGuy

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    Don’t let the messenger cloud or bias you from the message.

    I’m as big a fan of Boeing as anyone.

    Feel free to show us why or where the video information is flawed, or non factual. That would help me, and everyone else here.

    edit - A good friend and 737 pilot said that no main stream media outlet is going to go after Boeing. They are soft pedaling the current problems with the company.
     
    Last edited: Apr 11, 2019
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  4. Apr 11, 2019 #4

    12notes

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    I don't doubt the individuals believed there were problems, but it would only really be disturbing if there were any catastrophic failures of the hull of a 737NG that actually happened to one of the 6,500 aircraft flying over the last 20 years. The people in procurement (the only ones actually involved in the article) usually don't get to make engineering decisions for a reason.
     
  5. Apr 11, 2019 #5

    TXFlyGuy

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    Just like they normally don’t let the engineers test fly the airplane. But it was not an engineering problem. It was a manufacture problem. With the evidence on the faulty parts plain to see.

    But hey...thousands of those flufs flying, with only one blow up that I’m aware of. So the odds are in our favor.
     
  6. Apr 11, 2019 #6

    12notes

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    The decision to use those parts and how they could be adjusted were an engineering problem. The procurement woman was horrified by adjustment shims being used. Not exactly her call.

    Which "blow up" are you talking about? I didn't find any looking up the 737NG models.
     
  7. Apr 11, 2019 #7

    Himat

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    I would not dismiss that news source straight away. Entering Boeing part quality issue in the Google search field did give these among the top five:
    https://www.bloomberg.com/news/arti...ntagon-over-quality-concerns-going-back-years
    https://www.seattletimes.com/busine...s-questioned-following-quality-control-audit/
    https://www.seattletimes.com/busine...halts-delivery-of-boeings-tanker-over-debris/

    Note that Al Jazeera is not tied tight into the US financial system, nor outside the US known as especially anti-American
     
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  8. Apr 11, 2019 #8

    TXFlyGuy

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    It was an older 737, Aloha. Blew it's top. I heard the inside story on this...the auto pressurization system was inop, so the crew had to run it in manual. They accidentally over pressurized the cabin, and the relief valves failed.

    Not really a fault of the airplane.
     
  9. Apr 11, 2019 #9

    Vigilant1

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    Does your friend think the news media is "soft pedalling" the 737 MAX/MCAS issue? Because my perception is exactly the opposite--where there has been an opportunity to paint Boeing as an irresponsible corporation, that's the way the story has been presented.
    Here's Al Jazeera's coverage, which is typical of US and foreign media coverage: ""The crew performed all the procedures repeatedly provided by the manufacturer but was not able to control the aircraft," Dagmawit said, citing data from the Boeing 737 MAX 8's recorders." This claim by Ethiopian officials has routinely been reported just this way without any context or additional information. The released flight data information reveals that the crew fought the trim for 2-3 minutes before turning off the two switches for the stab trim (autopilot and electric trim). Now, perhaps by that point the airspeed and out-of-trim control pressures on the stab jackscrew were too much to be overcome by the trim motors or use of the manual trim wheels. Look through the press coverage for that nugget, let me know if you find it.
    An analogy: A crew watches an engine fire light blink for 2-3 minutes, then cuts off the throttle and discharges the fire bottle after the fire has spread to the wing tank and is burning through the wing spar. Would we think it fair to characterize the situation as "the crew followed the prescribed procedure but still the wing burned off?"

    I am absolutely not saying that Boeing shouldn't improve the 737 MAX, and that crews shouldn't receive better training and info on the operation of the MCAS and other flight control systems. I'm saying that there are no signs that Boeing is receiving favorable treatment by the media. Quite the opposite.
     
    Last edited: Apr 12, 2019
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  10. Apr 12, 2019 #10

    TXFlyGuy

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    ""The crew performed all the procedures repeatedly provided by the manufacturer but was not able to control the aircraft," Dagmawit said, citing data from the Boeing 737 MAX 8's recorders."

    This is deeply disturbing, as a professional pilot, and as an individual who commutes to work every week, many times on the 737.
     
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  11. Apr 12, 2019 #11

    ScaleBirdsPaul

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    As long as the parts went through the proper Material Review Board process then I don't see an issue installing the parts on airplanes. I'm not familiar enough with the specific parts or defects, but I can imagine on something that large there are going to be lots critical and non-critical dimensions or features. I don't know what kind of edge margin was used, and I'm just speculating here, but I could see a situation where a 2D edge margin was called out based on a standard practice or Boeing spec, and if it comes in at 1.95D then it goes into MRB who will look at the actual stresses and as-built dimensions and determine that an appropriate safety factor still exists. This type of thing is very common in many industries I've worked in.

    The manufacturer falsifying data is absolutely unforgivable though, and I hope Boeing took proper action against them.
     
  12. Apr 12, 2019 #12

    Vigilant1

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    The allegation is that 737NGs are built with faulty parts that pose a serious risk to safe flight. These alleged inclusions of unsafe parts occurred more than 10 years ago, enough time to be showing up in accident stats we would think. So, are these planes unsafe? Falling from the sky in huge numbers?
    The actual flight safety data says the 737NG fleet is quite safe and has reliability comparable to other commercial aircraft. In particular: Over 6,900 of these 737NGs have been delivered to commercial customers over more than 20 years. There have been only 15 hull losses from all causes. The hull loss rate is .17 per million departures and just .08 per million departures for hull loss with fatalities (through 2017). The 737 NG has a lower hull loss rate and hull loss with fatalities rates than any Airbus type or model and any Boeing type or model (except the 717) that had accumulated at least a million departures. The 737NG has a fatal hull loss rate about 1/3rd the rate of the 737 variants it replaced (which were already good for their day). In short: The 737NG is one of the safest planes in airline service. Facts here (P 19): more enlightening than a shoddy Al Jazeera hit piece.
     
    Last edited: Apr 12, 2019
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  13. Apr 12, 2019 #13

    pwood66889

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    Whether from Al Jeezera or not, the build-vs-buy is hard in airplanes. First off, itt can be much cheaper to buy. And it is much cheaper to hand-stroke parts together (no 1-in-3000ths of an inch) than to buy computerized equipment that perform to that standare {You can let people go without having to sink the bank loan there on}. So a company will "outsource" so long as the supplier says they are doing it right.
    Now, in Japan, the company will visit the sub's shop to see what is going on. And the Japanese will reject (read: not pay for) parts that do not fit.
    Finally <rant> there are two ways to quality: Inspected in and process control. The former involves many (not cheap) eyes on the piece. The latter involves having enough parts being made for the statistics to work out.</rant>
    And lastly: each job is a stepping stone. Do not leave the stone you are on unless you have another one. I'm retired, of course.
     
  14. Apr 12, 2019 #14

    Wanttaja

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    As a Systems Engineer with 40 year's experience in the Air Force and Boeing, I place the blame for this on Systems Engineering. The failure mode for these accidents should have been identified, the potential for occurrence computed, and appropriate mitigation implemented.

    Mind you, I never worked on an aircraft program. But launched 17 satellites without a failure.

    Ron Wanttaja
     
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  15. Apr 12, 2019 #15

    12notes

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    I'm fairly sure that the tolerances are 0.003", the reporter heard "three thousandths of an inch tolerance" and came up with a 3000th of an inch.

    Unless 0.0003333.... is a common tolerance I've never heard of.
     
  16. Apr 12, 2019 #16

    Doggzilla

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    What surprises me the most is that the 737 MAX even exists. The 787 is not that much more expensive and saves fuel.

    I assume it was mostly because it did not require additional training for their existing 737 pilots.

    But from a financial point of view... the 787 looks vastly better. Unless Im missing something important.
     
  17. Apr 12, 2019 #17

    MadRocketScientist

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    I think the reason is that the 787 is only more efficient on long haul flights and not so good at short haul hops. The 787 would also need a different rating for the crew that flies it. If the airline doesn't have any 787's, I am guessing it would cost a lot more than using another 737 with a common type rating.

    Air New Zealand has some 787's sitting on the ground due to not having a long enough ETOPS rating due to the Rolls Royce engine debacle. They still fly the A340's on our domestic routes rather than using the 787's.
     
  18. Apr 12, 2019 #18

    Himat

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    0,0003333... could be a common tolerance. Check SI measurement units and tolerance, round to nearest US measurement. To be able to procure parts internationally, Boeing must have the drawings in SI units. Note that most CNC machines default to SI units.
     
  19. Apr 12, 2019 #19

    davidb

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    I find the quote disturbing because the crew actually did not adhere to the procedure. We have some insight into why they might have done the wrong things so I don’t think it’s fair to place all blame on the crew either.
     
  20. Apr 12, 2019 #20

    markaeric

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    The parts in that article not being made to spec would be but a fraction of the total quality issues each plane has, with some being identified and corrected in a way deemed acceptable by engineering, while plenty others go unnoticed/unreported unwittingly or otherwise. By what I've heard from friends that work at Boeing's old Wichita plant now owned by a supplier producing the 737 fuselage, it's a mad house which is not surprising considering how short of a time they've been given to ramp up production to 50+(!) units a month. People are overworked, there's not enough inspectors (an effective way to have worksmanship issues overlooked), along with deadlines that have significant financial repercussions if not met which further fosters a culture of letting problems slide. It also doesn't help when the off-shifts tend to be primarily staffed by people with the least amount of experience, so you have huge skills and knowledge gaps between the shifts which creates issues some companies seem to underestimate. The only thing that gives me comfort when flying is the hope that the plane had been over-engineered.
     
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