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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

#591

Post by pests »

Rapzid wrote: post #246
fshbbdssbbgdd wrote: post #145

Check out this video showing how the plug is supposed to be installed: https://youtu.be/maLBGFYl9_o?t=540 Some of the bolts that would be loosened when the plug is opened during maintenance have a pin to prevent them from turning. That pin is present in this photo: https://x.com/byerussell/status/1744460136855294106?s=46&t=s... However, the same photo shows other critical bolts that hold the whole hinge on the door a…

"Loose bolts" is not a ton of detail. It could have nothing to do with any of the bolts discussed in that video. I'm having a hard time imagining how this failure could occur from just those bolts "needing tightening". They are lock bolts with pins and appear to take shear forces and provide no clamping functionality. Even if the bolts were "loose", or not torqued to spec, how would they come all the way undone? Then…

The bolts themselves don't take the entirety of the shear forces. They provide tension and therefore friction between the mounting surfaces which is where the shear is handled. By being loose, there is no friction to handle shear and also the item can gain additional momentum (more distance to travel) during shakes and impacts which might increase the impact force above the rated strengths strength.

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

#592

Post by kakwa_ »

markdown wrote: post #589
RF_Savage wrote: post #576

Earlier quoted context omitted.

The management imported from McDonnel-Douglas? The same management that drove it to ground? The fish rots from the head. And these constant problems sure do sound like a new company culture of cutting corners instead engineering first.

> The management imported from McDonnel-Douglas? I've heard this since they killed hundreds of people in the two crashes. Why are they being protected? They have names.

It's not necessarily a question of persons (and the CEO did a resigned after the Max crashes).

It's more a question of culture (oversimplifying, sales vs engineering) and this is harder to change most of the time. Apparently, even the Max debacle was not enough.

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

#593

Post by mihaaly »

consumer451 wrote: post #400

This is the the best update I have seen so far on the incident Alaska Max 9. The presenter is a 777 pilot and A&P mechanic. Released 2hrs ago. https://www.youtube.com/watch?v=WhfK9jlZK1o [13:43]

A scary comment from the video:

"I’ve been an aircraft technician for 23 years and we operate the Max9. I’ve opened and closed one of these plugs as well. Keep in mind that other 737 NG’s have these plugs installed in the longer fuselage models, not just the Max. They all work the same way and there’s never been an incident like this. I’m not saying this is what happened, but I can’t see how this could lug could come loose unless the two upper capture bolts, and the two lower bolts through the spring hinges weren’t installed. Even if a set of bolts, either uppers or lowers were missing with the opposites installed, I can’t see how the plug could come loose and depart the airframe. Just my ten cents. " - @jeffropenn

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

#594

Post by midasuni »

leetrout wrote: post #85
thinkingtoilet wrote: post #69

Earlier quoted context omitted.

>People at large simply cannot be bothered to care about anything People care deeply about a lot of things, just not this. And why should they? When you have every business decision made either by private equity or public companies with a focus only on the next 90 days it turns out everything goes to shit. Wages are stagnant. Wealth inequality is massive. Our society is sick. Issues like this will only increase. Our…

Random aside: I looked up an Acela ticket this morning. $1000 for a first class ticket from DC to BOS. 6.5 hours. Same flight first class with Delta this week is $850. Also 6 hours with layover. Blows my mind first class rail travel is as much as first class air travel.

I’d expect rail to cost far more

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

#595

Post by bgnn »

gostsamo wrote: post #47
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...

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.

EU literally followa FAA: https://www.businesstravelnewseurope.com/Air-Travel/EU-airli...

"The European Union Aviation Safety Agency (EASA) said it had also adopted the FAA’s Emergency Airworthiness Directive (EAD) to ground this particular. ...

configuration of Boeing 737-9. “EASA took the decision to adopt the FAA’s EAD despite the fact that - to the agency's knowledge and also on the basis of statements from the FAA and Boeing - no airline in an EASA member state currently operates an aircraft in the relevant configuration,” said EASA in a statement"

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

#596

Post by leptons »

RF_Savage wrote: post #576
MarkMarine wrote: post #573

I was responsible for safe for flight inspections on military aircraft and the photo included in that post is completely insane to me. Those bolts being loose (and they are BIG bolts) would mean multiple people in the installation process didn’t do their jobs, and signed their life on the line saying they did. When I did maintenance, there was someone (QA) there to witness every torqued bolt, inspect every safety wir…

The management imported from McDonnel-Douglas? The same management that drove it to ground? The fish rots from the head. And these constant problems sure do sound like a new company culture of cutting corners instead engineering first.

The "MAX" in 737 MAX means "maximum profit", not "maximum safety".

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

#597

Post by whatever1 »

MarkMarine wrote: post #573

I was responsible for safe for flight inspections on military aircraft and the photo included in that post is completely insane to me. Those bolts being loose (and they are BIG bolts) would mean multiple people in the installation process didn’t do their jobs, and signed their life on the line saying they did. When I did maintenance, there was someone (QA) there to witness every torqued bolt, inspect every safety wir…

Bolts can get unscrewed with vibrations. So probably a design error, they did not use the correct type of bolt (the one with the safety pin).

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

#598

Post by siva7 »

leptons wrote: post #596
RF_Savage wrote: post #576

Earlier quoted context omitted.

The management imported from McDonnel-Douglas? The same management that drove it to ground? The fish rots from the head. And these constant problems sure do sound like a new company culture of cutting corners instead engineering first.

The "MAX" in 737 MAX means "maximum profit", not "maximum safety".

You're joking but it's the real meaning conveyed to their customers, the airliners.

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

#599

Post by rob74 »

markdown wrote: post #589
RF_Savage wrote: post #576

Earlier quoted context omitted.

The management imported from McDonnel-Douglas? The same management that drove it to ground? The fish rots from the head. And these constant problems sure do sound like a new company culture of cutting corners instead engineering first.

> The management imported from McDonnel-Douglas? I've heard this since they killed hundreds of people in the two crashes. Why are they being protected? They have names.

Because the shareholders like the management? Cutting corners to increase (short-term) profits is more popular with them than focusing on quality. And now that the company has been in the red consistently since 2019 (https://www.statista.com/chart/20660/boeing-earnings-loss/), of course the answer has to be to lower costs even more wherever possible in order to return to profitability...

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

#600

Post by _glass »

irrational wrote: post #518
amluto wrote: post #478

Earlier quoted context omitted.

> We have software QA departments that operate very much like manufacturing or aerospace QA. I don’t work in this industry, but this seems fairly ridiculous on its face: software is not at all like manufacturing. In manufacturing, there’s a design and a manufacturing process, and a critical function of QA is ensuring that the manufactured produce is manufactured to spec. With software, the software is written, compil…

Ideally there should be a solid spec written and then qa can test against the spec. Maybe there is somewhere that does write solid specs, including accounting for corner cases, but in my 25 years working professionally in the industry, I’ve never seen it.

I work in MedTech. We do this. A design has to be reviewed by QA, and is then tested, and the test is reviewed again. So just to counter the narrative, there are companies that do that, and it is working. In other jobs I also saw the cargo cult of QA. But in some industries it is just crucial, otherwise the pressure is too high to cut corners to implement something. It is a good mechanism to counter the need to move fast and break things.
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