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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

#671

Post by storf45 »

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…

From when I worked as an engineer on the assembly line for smaller jets, know that there would be a record trail of exactly who completed the work, who signed off on it and what the work order steps were for anything related to these assemblies and components. This would include the work done at Boeing and their suppliers. Will be interesting to ultimately hear the root cause here.

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

#672

Post by alexpc201 »

anonfromsomewhe wrote: post #628
FerretFred wrote: post #570

Was there ever an aircraft more cursed than the 737 Max? Sounds like it was designed by a team of accountants.

Concorde ? maybe? it literally changed the industry online to be cancelled later

The Concorde has been one of the safest airplanes in history, with only one accident in 30 years of service. The story is different for the Tupolev Tu-144, also known as Concordoski, a copy of the Anglo-French plane.

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

#673

Post by 0xbadc0de5 »

somewhereoutth wrote: post #625
whatever1 wrote: post #597

Earlier quoted context omitted.

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).

My understanding is that the bolts did have castle nuts and retaining wires in the design. So either they were incorrectly fitted, or the bolts themselves were under specified with regard to strength.

The door hinge bolt had a castellated nut and pin, but the screws holding the hinge mount to the airframe apparently had no retaining wire. See leaked photo at: https://twitter.com/ByERussell/status/1744460136855294106/ph...

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

#674

Post by legacynl »

vegetablepotpie wrote: post #405
ethbr1 wrote: post #371

Earlier quoted context omitted.

I expect even at its worst, software development could learn a lot from aircraft QA. Especially since most shops have pretty much tossed professional career QA out the window.

I work in the defense industry, it’s very much like the aerospace industry in that we deal with human life as a consequence of our work. We have software QA departments that operate very much like manufacturing or aerospace QA. Software QA provides nothing of value to software development; having it as a dedicated function works against the overtly stated goals of the function and counterintuitively acts to degrade q…

I think you're sort of misunderstanding the role of QA.

You think that QA is a liability shield, but that is only a side effect of the work that they actually do.

The task of QA is exactly that: an entity that tries to assure that the quality is up to some standard. Even in favourable conditions mistakes happen, so how do you make sure as a company that not 1 in every 100 product are faulty and tarnishes the good reputation that your company has spent so much time and money on to build? You hire a QA to make sure problems get caught before delivery.

But if all humans make mistakes, and QA is human, how do you make sure that the QA doesn't make a mistake? A never ending chain of QAs expecting each other?

No of course not. One thing that helps with reducing errors is to have a rigid protocol that is followed to the letter everytime. Pilots, for example, have a preflight checklist that they have to run every time they operate the plane.

The rigid protocol of QA teams is therefore an essential part of their jobs.

Although from your standpoint as a developer it might seem strange that QA is 'preventing' you from fixing a bug, it is actually very reasonable.

Especially since you work in the defence industry, I hope you understand that it is very important that the software that operates radars, planes, missiles, bombs, etc is working exactly as expected. Understandably there is a great deal of effort made to assure that when those things are needed they work exactly to spec.

So in your example it is probably very reasonable that any change you make needs to go through some rigorous process. The fact that it 'only' was about test equipment, doesn't matter because test equipment is just as, if not more important as the stuff it tests.

The reason why QA has the side-effect of being a 'liability shield' is that it gives companies the ability to argue (and proof) after the fact that the company did their due diligence in making sure that the product was to spec.

Especially certification is basically to get an external organisation to approve your QA. In that case if you get sued you can rightfully claim that you did everything that was legally asked of you, and if there is blame, then it is the certifying company using insufficient standards.

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

#675

Post by em1sar »

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.

[dead]

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

#676

Post by croisillon »

aledalgrande wrote: post #225
croisillon wrote: post #61

Earlier quoted context omitted.

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

it seems healthy to have at most a quarter of each main models

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

#677

Post by MarkMarine »

DANmode wrote: post #665
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…

> signed their life on the line Clearly this is hyperbole.

It wasn’t in the military. Doing this would land you in Leavenworth.

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

#678

Post by acdha »

bb88 wrote: post #520
acdha wrote: post #491

Earlier quoted context omitted.

This wasn’t related to autopilot and they removed mention of the MCAS system from the documentation to support the main selling point of the 737 MAX, which was that existing 737 pilots would be able to switch easily without recertification. They knew that they’d lose most sales to Airbus if the aircraft were compared on their merits so they were banking hard on their huge pool of certified pilots as the competitive e…

You might enjoy this. I have a pin that blinks "AOA Disagree". Back when I flew regularly before covid, I was tempted to create a bunch of these and hand them out to the flight crew for the flights I flew on.

Ha, playing hardball! I wonder whether you’d find pilots who are Boeing loyalists who’d take offense, or if those guys are even madder at the current management for letting them down.

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

#679

Post by ethbr1 »

shiroiuma wrote: post #564
fzingle wrote: post #552

Earlier quoted context omitted.

> Does it make sense to degrade the performance of good software teams because bad software teams exist? Consider the classic statistic "most drivers think they are above average". I posit that the same is true of software teams, almost every team will self-assess as above average, i.e. good. Those teams will then imagine that, being good, they build quality into the process and very little verification QA is done. I…

I'm curious: in your many years of being a consultant to these bad teams, where the manager really thought they were top 20%, did you get a chance to talk to the rank-and-file team members, and did they paint a very different picture of the team health and software quality than their manager? Also, did you run across any orgs where they basically refused to use a process like Agile, and instead just did ad-hoc coding…

Not parent, but in my experience as a consultant working with bad teams, the rank and file were 'doing the job.'

You usually had a few personality archetypes:

- The most technical dev on the team, always with a chip on their shoulder and serious personality issues, who had decided to settle for this job for (reasons)

- The vastly undertrained dev who was trying to keep up with the rest of the team, but would eventually be found out and tossed, usually to blame for a major issue

- The earnest and surprisingly competent meek dev, who presumably didn't have enough confidence to apply to a better job, but easily could have made it on merit, work ethic, and skill

- The over-confident dev who read a bit of SDLC practice, and could see every tree while missing the forest

The key is that, aside from the incompetent person, they had all always been working there for awhile. Consequently, there wasn't good or bad health and quality: there was just "the system" (at that company) and dealing with it.

And none of these folks ever worked at 5-person startups. ;) I think it was definitely more an issue of SDLC "unknown unknowns" they should be doing, than willful decisions not to.

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

#680

Post by defrost »

stjohnswarts wrote: post #661
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…

Did you torque every bolt every time before every flight?

Every scheduled maintainance that had that on the punch list, yes.

With a seperate follow through by another party to check the work.

That's SOP for US | AU | UK | EU military air mechanical crews.

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