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United finds loose bolts on plug doors during 737 Max 9 inspections

theaircurrent.com

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Re: United finds loose bolts on plug doors during 737 Max 9 inspections

#291

Post by hef19898 »

AnthonyMouse wrote: post #271
jerlam wrote: post #200

Earlier quoted context omitted.

Not sure that would help - the Boeing subcontractor that likely played a role in the defective parts, Spirit Aero, was previously part of Boeing and spun off in 2005.

If Boeing has insufficient competition, they don't have to care because their customers have limited alternatives. If they don't have to care then they don't have to care if their subcontractors care. They also have limited fear of regulators because the US government will be wary about damaging the country's sole supplier in an important industry. Break them up and it's easier for both the market and the government…

And how would you break up Boeing to create more competition for civil airliners exactly?

Re: United finds loose bolts on plug doors during 737 Max 9 inspections

#292

Post by masklinn »

0cf8612b2e1e wrote: post #202
rconti wrote: post #160

So, about that Max 10 on which you were hoping to get fast-track approval...

Airbus must be having a fantastic week.

Probably gives them some succor given the engine issues they’ve been having.

Re: United finds loose bolts on plug doors during 737 Max 9 inspections

#293

Post by Rapzid »

stefan_ wrote: post #221
Scoundreller wrote: post #34

Earlier quoted context omitted.

Or it means the torque specs were a little too low, or too high and stripped, or the bolt threading was defective/spec’d wrong. Or bad metallurgy. Or the spec didn’t specify which order to tighten the bolts, so which direction you go causes different outcomes. Lots of stuff is assembled consistently and carefully “wrong”, but as specified.

To be fair it seems there is an image of some of the loose bolts: https://nitter.net/ByERussell/status/1744460136855294106 I think this should stick out to an assembly person as not quite right.

That lock nut may not have lined up correctly for some reason and was backed off a bit to get the pin in? That could make it torqued under spec. But also, it doesn't look like that bolt clamps anything so it may not matter if it was a little "loose"..

Re: United finds loose bolts on plug doors during 737 Max 9 inspections

#294

Post by Scoundreller »

KptMarchewa wrote: post #186
outside1234 wrote: post #153

Such a crappy aircraft - can we just get rid of these already?

Force it to develop actually new airplane, not rely on grandfathered type license from 60 years ago.

I wonder what automotive designs would look like if we allowed that kind of grandfathering. Or maybe we do but people keep wanting new car designs?

Re: United finds loose bolts on plug doors during 737 Max 9 inspections

#295

Post by Rapzid »

CobaltFire wrote: post #234
stefan_ wrote: post #221

Earlier quoted context omitted.

To be fair it seems there is an image of some of the loose bolts: https://nitter.net/ByERussell/status/1744460136855294106 I think this should stick out to an assembly person as not quite right.

Note that, as a comment there states, there are tool marks indicating the bolts were both tightened and loosened at various points. Complicates the issue of who is at fault; where/when were they loosened?

Maybe it was opened for maintenance reasons after it was initially installed. Maybe it was torqued twice to get the lock pin through.

Re: United finds loose bolts on plug doors during 737 Max 9 inspections

#296

Post by bastardoperator »

infotainment wrote: post #169
outside1234 wrote: post #153

Such a crappy aircraft - can we just get rid of these already?

Agreed — while we’re at it, let’s break Boeing up into multiple firms. It has been “too big to fail” for too long.

I've said it here before, but working with Boeing, every project might as well be a different company.

Re: United finds loose bolts on plug doors during 737 Max 9 inspections

#297

Post by plagiarist »

consumer451 wrote: post #164
ChatGTP wrote: post #136

Earlier quoted context omitted.

Because those things are a joke ?

Please refresh and look at my edit. If a missing some major required component aside from finetuning and frames per sec, which will require a few years for everything to be fast enough... please let me know what it is. Wait, oh it will be understanding of time... the sequencing of the frames. That is missing for now, right?

I think you're giving it too much credit for solving examples that are obviously wrong. Not only a non-expert but even most children know those pairings don't go together.

Given that the discussion in this post is around torquing to the right specifications, I don't know if just fine tuning is enough. It might need more serious training on videos of assembly. Even then, can it distinguish between the right torque or not from video?

I think it's interesting, but you should deliberately try to make it fail to see where the edges are. Like hold a wrench of the obviously wrong size next to a nut and ask if that will work. Force perspective so they look the same size. See if it will prevent you from mixing potentially dangerous chemical combinations. Will it warn you to wear protective eyewear when using a circular saw?

Re: United finds loose bolts on plug doors during 737 Max 9 inspections

#298

Post by kube-system »

adrian_b wrote: post #253
kube-system wrote: post #166

Earlier quoted context omitted.

Bolts can be loosened, or fail to be tightened on any aircraft. I suspect this may be a problem with people and/or procedure.

Since the aircraft with the incident was extremely new, it is pretty certain that the bolts have not been properly assembled at Boeing, so the problem is with their assembly procedures.

The fuselage of this plane is not built by Boeing. It could be an issue with the contractor, Spirit AeroSystems, who builds it. It could be an issue with some other final configuration procedure. We'll need to wait for the investigation to conclude.

Re: United finds loose bolts on plug doors during 737 Max 9 inspections

#299

Post by quickthrowman »

queuebert wrote: post #58

I've seen on Toyotas and also at Universal Studios bolts on rides are marked with paint presumably to indicate that the nut hasn't backed out. Are airliners marked in this way? Is checking the bolts simply a visual inspection, or do the inspectors need to get out a torque wrench?

> I've seen on Toyotas and also at Universal Studios bolts on rides are marked with paint presumably to indicate that the nut hasn't backed out.

This is also standard procedure for electrical maintenance inside distribution equipment. Every lug/termination is torqued to spec and then marked to indicate it has been torqued down. This should be done regularly to prevent any loose terminations from causing an arc flash.

Re: United finds loose bolts on plug doors during 737 Max 9 inspections

#300

Post by ajb257 »

bobsomers wrote: post #284
Aqueous wrote: post #247

Literally just flew on a United Airlines 737 MAX 9 one week ago. It seems like the craft I flew on has probably been grounded in the week since. I noticed that we were flying on a MAX before boarding and nearly asked to switch flights, but consoled myself that I was being irrational and that the planes were almost certainly fine now. Guess my confidence was misplaced.

FWIW, it's only the Max 9s which have this issue. The Max 7s and 8s don't have an exit in that location (too few seats) and the Max 10s require an exit door to be installed in that location, not the door plug. It's only the Max 9s that have the option of the door plug, if the installed seat count is below the threshold where an additional exit is required.

I think the concern is more the attitude that allowed this to happen, despite all the issues Boeing has had.
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