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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

#221

Post by stefan_ »

Scoundreller wrote: post #34
Syonyk wrote: post #20

Earlier quoted context omitted.

No, it's as insane as it reads. It means people were careless and sloppy during assembly. Think of it like seeing "one cockroach in your kitchen." It's not one cockroach. You just haven't opened up the rest of the walls.

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.

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

#222

Post by phkahler »

gruez wrote: post #121
intunderflow wrote: post #6

At what point do consumers en-masse refuse to fly on these aircraft, if ever? When there's a few more fatal crashes?

Statistically speaking it's not worth worrying about. In 2021 there were less than 0.001 deaths per 100M passenger miles. Assuming these aircraft are 10x more dangerous than the alternative, that works out to 0.01 deaths per 100M passenger miles, or 0.00000026 deaths NY to SF flight. For an average american aged 38.9 years[2] with 40 years of life left[3], that works out to a loss of life of 5.4 minutes. I don't thin…

A better metric IMHO is "crashes involving at least one fatality" per flight. For large aircraft the fatalities are often everyone on board or nearly so. So people care about "what is the probability that the flight I'm getting on has a fatal accident?" This is largely independent of number of passengers or miles flown.

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

#223

Post by jupp0r »

Kluggy wrote: post #205
dataflow wrote: post #163

How were these not noticed in proper inspections? Is this the first time these planes have been inspected?

They generally don't disassemble the entire plane every time they get inspected...

IIRC every bolt's torque value needs to be logged any time it's (re)fastened. At least that's true for aircraft engine maintenance, not sure if it applies to the assembly process of the airframe, I'd sure hope so!

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

#224

Post by gostsamo »

vidanay wrote: post #55
gostsamo wrote: post #47

Earlier quoted context omitted.

There are mutual recognition agreements between the regulators and if the europeans try something like that, the americans can create counter measures to even the field in a mutually undesired spiral. At this moment, the biggest enemy of Boeing is Boeing itself.

We don't care if people die, just so long as your enforcement is not any more rigorous than ours!

It is more like "our cooperation is more valuable than temporary monetary advantages which could be negated and which could leave everyone worse overall". I'm not sure why deliberately misinterpret my comment, but you are quite wrong. The first 737max precedent is quite instructive for the relationship between the two regulators.

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

#225

Post by aledalgrande »

croisillon wrote: post #61
hmottestad wrote: post #32

Earlier quoted context omitted.

Maybe when airlines start advertising that they don’t use the new 737s. The more likely scenario is that the Chinese or Europeans will ground the new 737s until some very expensive fix is put into place and not accept any workarounds. That would probably make a difference. FYI: https://qz.com/1569865/china-grounds-737-max-8-after-ethiopi...

from a cursory check https://en.wikipedia.org/wiki/List_of_Boeing_737_MAX_orders_... there are not that many 737 MAX in Europe: * Ryanair (124 planes out of 575) * TUI (40 planes out of 134) * Turkish (25 planes out of 400) * Norwegian (18 planes out of 81) * Icelandair (3 planes out of 47)

Went to check on Air Canada and I thought they had way more, but they only have 40: https://en.wikipedia.org/wiki/Air_Canada_fleet

and aside 787s, they haven't ordered any more Boeings

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

#226

Post by jacquesm »

dralley wrote: post #181
zokier wrote: post #105

Earlier quoted context omitted.

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

And you seem to be assuming that the problem is in the design and not the assembly... The latter seems more likely.

You are both missing the 'faulty process' and 'faulty communications' options.

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

#228

Post by fulladder »

baq wrote: post #21
napoleoncomplex wrote: post #7

On at least 5 airplanes? Of one airline? Are loose bolts a minor issue, or is it as insane as it reads?

It's a cliche thing to say, but if it was a known issue and management papered over it - as the alternative is incompetent engineering instead of just cost-center-managed engineering - someone should go jail?

Nah. When you have an engineering culture problem, putting people in jail is not going to solve anything. It will scare employees, sure, but it won't fix your culture.

I believe someone at Boeing actually was criminally prosecuted in connection with the earlier MAX 8 problems, but, as in all these situations, it is seriously unlikely that that fixed any actual problems. Most likely, somebody felt they needed a neck to wring and found a convenient scapegoat.

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

#229

Post by epicureanideal »

ramesh31 wrote: post #218
outside1234 wrote: post #153

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

>Such a crappy aircraft - can we just get rid of these already? It was a beautiful aircraft, destroyed by years of management comittees. Boeing needs to be broken up and reorganized, full stop. Congress has to act. It is simply too important and vital of a company to US strategic interests to be left in this state.

Maybe Apple, or Elon Musk, or some other person or company with a spare hundred billion could spin up a decent aircraft company?

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

#230

Post by jacquesm »

myself248 wrote: post #219
pluc wrote: post #119

Earlier quoted context omitted.

Yeah this isn't a plane issue, it's a guy holding the drill issue as far as I understand it

If a guy holding the drill CAN cause this issue, that means there's ALSO a drill calibration issue, a bolt inspection issue, an inspection recordkeeping and doublechecking issue, etc. Humans make mistakes. The whole point of modern manufacturing is to make products better than any human can make them, by layering processes and procedures to catch those mistakes before they get out the door, and continually improve th…

Spot on, this is exactly the problem: you can't have 'just loose bolts', it's a whole raft of other issues.
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