Comment by fshbbdssbbgdd | Hacker News Reader

Comment by fshbbdssbbgdd | Hacker News Reader

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More rampant speculation!

Some quotes from this article: https://www.reuters.com/business/aerospace-defense/spirit-ae...

> As part of the production process, Spirit builds fuselages for 737s and sends them by train with the special door assembly “semi-rigged,” one of the people said.

> “They are fitted but not completed," the person said.

> At its Renton, Washington, plant, Boeing typically removes the pop-out, or non-functioning, door and uses the gap to load interiors. Then, the part is put back and the installation in completed. Finally, the hull is pressurized to 150% to make sure everything is working correctly, the person said.

I can imagine a diffusion of responsibility as to whose job it is supposed to be to tighten those hinge bolts. Spirit is installing the plug in a “semi-rigged” state. Boeing is removing the plug to load the interior, then reinstalling it. I’d hazard a guess that Boeing is not removing the hinges, because the plug can be removed without doing so. What if, when reinstalling the plug, Boeing workers just redo the stuff they removed? They tighten the vertical movement arrestor bolt, put the pin through it, and believe they have done their job? If they never messed with those other hinge bolts, they don’t bother tightening them?

I’m no MBA or aerospace engineer, but why sub-contract the fuselage? I get subbing engines, since engine designs can be used on/adapted to other (possibly non-Boeing) airframes, hence opening up economies of scale, etc. But the fuselage is most of the plane by mass and integral to the design of everything else. If you don’t like making fuselages, maybe you should get out of the aircraft business. Was this just a union-busting thing?

Spirit was spun out of Boeing

I don't always love the video format but Mentour talked about Spirit, Boeing, and the 737 MAX a few months ago: https://youtu.be/SmJgweFmoxs

The discussion about snowman hole issues and other problems is really alarming.

Engines are weirder. My understanding is that the airline specs out what the engine requirements are, and any engine manufacturer is allowed to try to meet that requirement.

Customers get to decide which engine to fit and negotiate for them separately from the aircraft.

Sometimes there's only one choice, but other times gives you a chance to have the same (or similar) engine to maintain across your fleet (or avoid that to avoid a total grounding) and whatever other reasons to choose one over the other.

At least that's what the A380 tour in Toulouse said. Kinda makes sense to at least keep the big aircraft builders from throwing too much of their weight around.

>Was this just a union-busting thing?

Yes, and to lower compensation because Boeing’s benefits are probably better than Spirits, and so if Boeing wants to pay the people that make the fuselage less, then having them be employed by someone else helps them pass non discrimination testing for pre tax benefits offered to Boeing’s higher compensated employees.

Also, lower unemployment insurance premiums if they want to reduce the amount of labor they buy, since Spirit would be the one laying people off.

Boeing sold the division that makes the fuselages. Could have been for any number of reasons.

There’s no way that this is what happened. They’re not building IKEA furniture, everything is tightly check-listed.

Evidently not though....

> Evidently not though

Bolts can be loosened by the physical and thermal stresses of use if there is a design flaw. So it’s not evidently an assembly QA problem.

The plane that lost a plug mid-flight was only two months old though. A design problem probably would have shown up in an older one.

> A design problem probably would have shown up in an older one.

Maybe, unless it required really specific conditions that have only occurred for this one or also required some maintenance snafu that also had nothing to do with Boeing assembly QA. We don’t have enough data to establish anything as the most probable explanation yet.

According to the linked article: at least five aircraft. So, not unique to this one. Or the one that blew the door out.

Surely you've heard of reliability bath-tub curve.

Uh, first part of the bath tub curve is driven by manufacturing defects... That's not a counter point at all.

That curve applies to design issues as well, they are more likely to be found in the very beginning (teething problems) as well.

You're talking out of your ass. Watch this documentary about whistleblower complaints as far back as the 737 NG line as they observed workers beating structural parts into place with hammers. Clearly, things haven't improved since then. https://youtu.be/IaWdEtANi-0

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