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

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

#231

Post by plagiarist »

fulladder wrote: post #165
CaptainMarvel wrote: post #116

Earlier quoted context omitted.

Do you mean that the train is _as cheap_ as taking a plane? In my experience, in the UK, taking a train is more expensive than taking a flight (or driving, for that matter).

Why do people pay more for slower transportation?

I'd pay extra to take the train for shorter trips. The entire experience is better, from not passing through a security theater production to the larger seats. I've never had a train sitting on the tarmac for hours, either, my plane trips frequently involve waits and delays.

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

#232

Post by tavavex »

consumer451 wrote: post #187
tavavex wrote: post #171

Earlier quoted context omitted.

The reason why it's bad is that this is an overcomplicated process that introduces potentially unreliable bells and whistles for little upside. At the end of the day, there aren't fundamental issues with a trained employee following a checklist. Machine learning is extremely powerful but tons of issues can be solved in a straightforward algorithmic fashion, so we should really be using it where it could make a big di…

Thanks. I get it, and generally agree with your point here. Paying for good people and giving them enough time to get the job done is generally enough. I was just trying to be fair to op's question as devil's advocate. I don't think it should just be dismissed as a joke. I have always been a huge cryptocurrency skeptic, and I just don't see the same trajectory for ML. So back in the day, Expert Systems were a big thi…

Yeah, I understand your sentiment. I hope I didn't appear to technologically conservative in my comment, it is kind of a minor pushback to people promoting generative AI as a panacea that makes every problem ever easier.

I can't tell you about what Boeing does with expert systems. I've never been employed by them and I never really looked into it or where they use them. It's especially unclear because Boeing does a lot more than just pure manufacturing.

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

#233

Post by intrasight »

hunterjrj wrote: post #124
psunavy03 wrote: post #104

Earlier quoted context omitted.

. . . and the US airline industry has still not had a fatal crash in just under 25 years.

Unfortunately there was one in the Buffalo area in 2009: https://en.m.wikipedia.org/wiki/Colgan_Air_Flight_3407

Beverly Eckert, Sept. 11 Widow and neighbor of a friend, died on that flight. Still makes me sad for their family.

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

#234

Post by CobaltFire »

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.

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?

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

#235

Post by notahacker »

bad_alloc wrote: post #157

How is Airbus doing meanwhile? I didn't hear about any production quality issues in their aircraft.

Half the A320neo fleet needs to be grounded for 250-300 days over the next year due to engine manufacturing issues affecting their wear (which tbf is entirely Pratt & Whitney's fault). Airbus settled a $2bn suit last year with Qatar Airways over A350 paint jobs so bad they grounded them and refused to take scheduled deliveries. You'll hear more about Boeing than the rest of the industry put together because this is HN...

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

#236

Post by phkahler »

chippiewill wrote: post #129
blindriver wrote: post #101

Doesn’t this call into question the manufacturing of ALL 737 MAX’s including the 7 and 8 since they must use the same manufacturing process?

Only the max-9 has the door plug, the smaller airframes don't have that door, and the larger airframes always have the door fitted

Maybe Boeing will rethink their plan to claim all variants of the 737 are basically equal.

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

#239

Post by adrian_b »

zokier wrote: post #105
adrian_b wrote: post #50

There were only 2 possible causes of the incident, either the bolts had been replaced with bolts made from an inappropriate material, so they broke, or the bolts had not been assembled correctly, and they became loose. It appears that the latter is what happened. Perhaps those who did the assembly of the doors at Boeing did not use the right kind of washers that are needed to prevent the unscrewing of the bolts, or t…

You are assuming this is problem in the assembly and not in the design?

For loose bolts, incorrect assembly is by far the most likely cause.

It can be a design problem if the bolts and associated parts like washers have been substituted recently or if the assembly instructions have been changed recently, e.g. by specifying a different torque. If any such engineering change has happened recently, then that would be the likely culprit.

A resonance problem of the aircraft body as supposed by another poster seems extremely unlikely as that would have required significant recent changes to the aircraft body, which did not happen.

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

#240

Post by exabrial »

I have a dumb question: why "plug" the doors at all? Why not burn a row of seats and have an extra safety door? Was this at request of the airlines to "meet" minimum safety standards or was there a reason why it's "better" to have less exit doors?
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