Getting to the point where I’d never want to fly a Boeing again after the Max debacle.
Completely shocked they haven’t ditched this plane and owned up that cutting safety for fuel savings wasn’t worth it.
United finds loose bolts on plug doors during 737 Max 9 inspections
641–650 of 773 posts
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#642Earlier 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.
Not sure what happened from “the design” to “the field”. The two loosen bolts in the picture are not castle nuts.
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#643I 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.
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Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#644Is Boeing an example of 'too big' to fail?
ie one of the reasons it's not out of business due to the multiple failures over the Max is it's just too important to the US economy?
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#645Earlier quoted context omitted.
> That's not it. I mean, it is. The Pratt & Whitney engine issue which is going to ground half the MAX's rival's aircraft for a year because a manufacturing fault makes the engine turbine blades liable to crack garnered two threads and zero comments (Boeing got more for a fun story about paper planes!). Airbus being found at fault but acquitted of involuntary manslaughter by a Paris court last year for the AF447 cras…
> Airbus being found at fault but acquitted of involuntary manslaughter by a Paris court last year for the AF447 crash (a 2009 mid air stall with a few MCAS parallels) passed without comment “Company isn’t found criminally negligent in case where it pretty clearly wasn’t being criminally negligent” isn’t.. news. I’d be _really_ curious to hear what you think the MCAS parallels are (besides both cases involving a sens…
Ah...because HN famously never has any interest in tech litigation and definitely won't have anything to say if a court finds in Boeing's failure in several years time!
The parallels are fairly obvious: AoA sensors malfunctioned, the situation was recoverable but the pilots were confused by conflicting and absent cockpit feedback and lack of relevant training, the OEM initially placed the blame entirely on the pilot but the problem was resolved with a tech remedy. Plus a whole lot of scope for speculation about Airbus regulatory capture of EASA and whether a first incident should have lead to grounding etc. Sure, with AF447 the issue was sensors having a (known) proneness to systematic failure rather than lack of redundancy and the plane plummeted because a stabilisation system disengaged at the worst possible time. They're obviously also not exactly the same, and the Qantas Flight 72 (different software subsystem input conflict automatically pitches nose down) near miss was a closer analogue, but they're all related to critical software handling edge cases and how guidance and UX might have mitigated issues. But as I said, you won't get much of a picture of the aviation industry from HN.
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#646Earlier quoted context omitted.
About 2000, Software QA (and almost all traditional QA activities) were changed. The focus was on process over inspection. "Design in quality, do not inspect it into the product" Suppliers (to include software) were expected to manage the quality of the product they provided; the purchaser would focus on how they managed the process, not in the compliance of every part. This had a chance until software process was to…
Here's a stupid question: How do you know your process is good unless you inspect it? "Hey Bob I know you're a competent engineer, but don't worry about specifying a certain type of bolt or loctite, the untrained assembly personnel will figure it out. I'm sure they won't let 200 people die in a plane crash."
Make it impossible to use a wrong bolt, and train the assembly workers.
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#647Earlier 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.
[REDACTED]
737 Max 9s are made in Renton, WA.
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#648Earlier quoted context omitted.
> Airliner safety is insanely good. Because I dug it up for another comment, commercial carriers operating under Part 121 (roughly: scheduled passenger and cargo operation) had 4 fatal incidents in the last 10 years. [0] Totalling 6 deaths. In 10 years of US commercial carrier aviation. One of those was literally 'the engine exploded and threw part of the turbine into the cabin (and also shredded some of the wing)'!!…
Ya but your sample size is way too small to measure the death rate. Aircraft deaths are rare, but flying is too. The two MAX 8s that fell from the sky were 100% Boeing's fault and could have happened in the US. If 5% of airline traffic is in the US you can renormalize those hundreds of dead and you get dozens dead.
We know US pilots have been warning about the same issues that led to the deathly crashes later but were ignored. The thing is, one part of US commercial aviation being so safe is a lot of pilots responsible for the jet airliners are ex-military. Someone mentioned Southwest Airlines Flight 1380, yup, captain Tammie Jo Shults was one of the first Navy female fighter pilots. Miracle on the Hudson? Sully Sullenberger was an Air Force captain and training officer. Civilian training, no matter how good, is just no replacement for military training and experience.
I can't find specific numbers but estimates say about one in three has a military background. That's an awful lot.
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#649Earlier quoted context omitted.
> Totalling 6 deaths. In 10 years of US commercial carrier aviation. Okay, awesome. But how much of that was luck with the 737 Max that they didn't crash on US soil by US airlines?
How much was a rigorous safety regime and high quality training?
Military training. See my comment above: https://news.ycombinator.com/item?id=38925089
Re: United finds loose bolts on plug doors during 737 Max 9 inspections
#650Which is more likely: * Lazy production line worker hand-tightens bolts and forgets to torque them, faking the results on the electronic torque wrench (which records the tightening of every bolt). * A design flaw causes vibrations which cause these bolts to loosen.
> Lazy production line worker
Because of your inclusion of the assumed 'lazyness' of the first I assume that you think it's the first?
why do you think it's more likely that the line worker is lazy and the one that screwed up? why not the 'lazy' designer who thought it would be strong enough, or 'lazy' supervisors that forget to supervise, or the lazy quality-assurer that forgets to assure quality?
Everyone makes mistakes. If your whole organisation relies on nobody ever making a mistake, then your organisation isn't at risk of failing, but is certain to fail. Or alternatively the organisation has already failed in its duties, but the consequences of that failure just haven't popped up yet.