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

https://theaircurrent.com/feed/dispatches/united-finds-loose-bolts-on-plug-doors-during-737-max-9-inspections/

by etimberg • 3 years ago

506 709 3 years ago

armada651• 3 years ago

Given that these are plug-style doors even if these were bolts in the hinges it would not risk the integrity of the fuselage seal.

CydeWeys• 3 years ago

Maybe the plugs aren't flanged enough? If the walls are mostly flat you could see the bolts being load-bearing.

samstave7• 3 years ago

My money is on the window. It was compromised and then the plug/bolts/flanges structure was ripped out of the body.

iapark• 3 years ago

I found this video illuminating. The name is confusing because these aren’t plug style doors. They can open out like they did here without passing through components https://youtu.be/maLBGFYl9_o?si=Km8qfkEv2YLHDY2G

Animats• 3 years ago

They're not plug-style doors. They open outward. That's the problem.

Opening outward is mechanically riskier, but more likely to be useful in an emergency. The drill for plug-style over-wing exits: Remove cover from upper handle, grab upper and lower handle, yank upper handle, pull door inside, have 15Kg or more of door land on your lap, turn big clunky door sideways, pitch through hole so it's outside and out of the way, climb through hole. Training video.[1] Few passengers are likely to get that drill right in an emergency, and the flight attendants are in the wrong place to do it.

[1] https://www.youtube.com/watch?v=RCFzEg-t_Bk

rpeden2• 3 years ago

As an interesting comparison to your A320 video, it looks like the A320neo overwing exits are now outward-opening instead of plug-style: https://youtu.be/VhiYfyE3Vps?si=FuKeNfpd1pD4sgc_&t=47

loeg2• 3 years ago

Empirically, the things can fall out. So your assumption is mistaken.

chippiewill3• 3 years ago

They're only a plug when they're in the locked position. These bolts on the door plug prevent the plug from sliding into a position where it can come out.

pcurve• 3 years ago

not plug! https://twitter.com/NTSB_Newsroom/status/1744202059870831016

ethanbond• 3 years ago

Soothing to read this while waiting to taxi aboard a different 737 model flown by United!

partiallypro• 3 years ago

Luckily this seems to only effect one (newer) model of the 737, though you begin to wonder what was missed in the others.

emeril2• 3 years ago

at this point, I'd prefer to be on an older boeing than a newer one...:(

intunderflow• 3 years ago

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

t0mas88• 3 years ago

Unfortunately consumers don't have much choice, the airline can change which type operates a flight at any time.

However longer term if Boeing's reputation keeps getting worse that can motivate buying decisions by the airlines. That change will be a very slow one, because fleet changes cost a lot of money in training crews, changing maintenance etc.

For example KLM is changing their short-haul fleet from the 737 NG to the A320neo family, that will take many years to completely roll out.

neverartful• 3 years ago

True, but some airlines probably don't have any in their fleet. If worried consumers find out they could opt to not fly on those airlines.

fullshark• 3 years ago

I think it would require a fatal air crash of an American flight with a major celebrity on board.

psunavy032• 3 years ago

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

kube-system9• 3 years ago

There's a decent list of celebs who have died in aircraft accidents. The attention typically lasts for a single news cycle.

hmottestad5• 3 years ago

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...

gostsamo2• 3 years ago

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.

croisillon2• 3 years ago

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)

j-bos2• 3 years ago

https://news.ycombinator.com/item?id=38917569

makestuff• 3 years ago

I doubt ever, consumers have been proven to select the cheapest airline ticket. The average once-a-year flier likely has no idea what aircraft they are even flying on.

lokar2• 3 years ago

I wonder what fraction of seats/revenue come from people who take one or fewer trips per year.

im3w1l• 3 years ago

I'd be willing to pay a premium not to fly on such an aircraft but not too big, as even though they aren't quite as safe as they should be, my impression is that the risk is still fairly low. Something on the order of 5%

gruez4• 3 years ago

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 think most americans would worry over this, especially compared to other far more deadly threats like obesity.

[1] https://injuryfacts.nsc.org/home-and-community/safety-topics...

[2] https://www.census.gov/newsroom/press-releases/2023/populati...

[3] https://www.ssa.gov/oact/STATS/table4c6.html

tw04• 3 years ago

Statistically speaking it's not worth worrying about.

Those statistics don't really work out at all. They take number of miles and deaths, and nothing else. Let's say flown miles and driven miles are exactly the same for arguments sake. If the number of miles flown on planes were traveled by 4 million people, whereas the number of miles traveled by car were from 4 billion people, your likelihood of dying in a plane crash is FAR higher than by car if you're one of the 4 million who fly on a plane.

Miles and deaths alone are pretty poor metrics. There's also the part where I may only drive once or twice a week vs. the average which takes into account people who commute daily. So my odds of dying in a car crash are still lower. The frequency of travel seems just as pertinent as the miles traveled.

fulladder4• 3 years ago

Excellent analysis.

phkahler5• 3 years ago

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.

kube-system9• 3 years ago

People don't change their behavior much when things like this happen. When it comes around to the next big travel weekend, people will continue to book on whatever airline gets them to the right place at the right time for the right price.

Even when people have a direct ability to change what vehicle they travel on, like with car sales, safety incidents/features/records/etc have little impact to no on sales.

This is one of the reasons why transportation safety is regulated rather than being left up to market forces. Market forces don't really have an impact until the safety risk reaches some extreme levels.

0xffff24• 3 years ago

As far as I can see, there's no real way to communicate this preference to airlines. I won't book a flight on a MAX, but the airline can change the airframe at the last second and it's highly situational how willing/able I am to just refuse to fly if they swap in a MAX.

eterm3• 3 years ago

I've communicated it albeit very indirectly. When looking at holiday packages for this summer I looked up the route to see if it's a 737 max before booking.

It wasn't, it was an A320 as I expected.

plagiarist6• 3 years ago

The typical person does not have the information about these failures, won't prioritize better odds of survival over short-term savings, and do not have enough money to choose alternatives anyway.

arcticbull• 3 years ago

People are very bad at managing risk. Even with all this, a 737-NG is infinitely safer than getting in a car, and yet people drive every day. Getting into your sedan is several orders of magnitude riskier than a 737. You're far more likely to die en route to the airport.

Obviously that doesn't excuse Boeing, I'm just saying, by the numbers.

[edit] The US has 1.5 deaths per 100M passenger-miles driven. [1]

The 737 NG has hit 10,000,000 flight hours 5 year into operating. That should be around 500,000,000 miles flown. About 180 seats per plane makes that ~90B seat-miles. That's 0.0038 deaths per 100M seat-miles flown.

So the 737-NG models are about 400X safer per mile than a car.

The median American lives 17mi from an airport, so the safety break-even point is 13,600mi flown on a 737-NG, assuming your destination is also a median 17mi away from the airport. If you're flying less than 13,600mi on a given 737 one-way trip, you're more likely to die getting to and from the airport.

Unless my math is off. This is just napkin math.

[1] https://injuryfacts.nsc.org/motor-vehicle/historical-fatalit...

arrakeenrevived3• 3 years ago

I think HN really overestimates the impact of events like this with the general public.

The very first A320 demonstration flight crashed, killing 3 people, allegedly due to software issues in the new fly-by-wire system, and then involved allegations that Airbus had tampered with the investigation. The demonstration flight was mostly journalists on the plane. [0]

The A330 crashed on one of its certification flights due to an issue with the autopilot, killing all 7 onboard. [1]

Both went on to be some of the all-time best selling aircraft, and meanwhile today in this thread you have people touting Airbus as a paragon of safety. Humans have a short memory.

0: https://en.wikipedia.org/wiki/Air_France_Flight_296Q

1: https://en.wikipedia.org/wiki/Airbus_Industrie_Flight_129

I mention these two specifically because they're examples of high-profile failures attributed due to issues with the aircraft early in their lifecycle, but basically every single popular aircraft type (except the B777 and A350) have had serious issues and loss of life due to manufacturing defects, but still went on to be overall successes. Hell, people still flew on the DC-10 even after its _numerous_ issues like AA 191..

napoleoncomplex• 3 years ago

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

Syonyk2• 3 years ago

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.

Scoundreller7• 3 years ago

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.

hef198989• 3 years ago

Assembly was loppy, management either ignored or, even worse, encouraged it while QA was asleep. Which is really bad...

tyingq• 3 years ago

It means people were careless and sloppy during assembly.

Maybe. Could also be incorrect torque specs, bad parts, unexpected vibration in that area, etc.

Edit: Yes, none of these are good either. Just saying there are many possibilities.

dylan6042• 3 years ago

What's crazy to me is that these things do not roll of the factory line in large numbers. If it was a car plant or some other line where large numbers come off per shift, you could find that possibly one operator for one shift set their torque wrench to the wrong setting causing the finished items for that shift to be suspect. But seeing as not one plane rolls of the floor per shift, this is much more systemic like possibly the documentation was wrong or similar where it is persistently done incorrectly. Or maybe just the one plane for that one day that the worker incorrectly set their torque wrench that day.

dendrite9• 3 years ago

Well they left a ladder in the tail of a plane during assembly in the not distant past. It's not like just a couple screws or washers were left behind to rattle around.

An ex worked on a QA-type project related to production for them. It makes me wonder if some of the issues were more fundamental than that project could ever have addressed.

https://www.nytimes.com/2019/06/28/business/boeing-787-dream...

baz00• 3 years ago

In software this is a reboot or an apology to a client.

In aerospace this is dead people.

t-writescode• 3 years ago

When a junior software engineer drops a table in production, we don’t say the junior engineer was sloppy. We say the protections and process in place were bad.

I don’t like how the sentence in this parent comment blames individuals for process problems.

itronitron• 3 years ago

From Alaska Airlines...

> "Initial reports from our technicians indicate some loose hardware was visible on some aircraft."

Friendly reminder that 'some' can also mean most or all.

baq• 3 years ago

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?

j-bos2• 3 years ago

Did anyone go to jail for the previous Boeing MAX crashes?

fulladder4• 3 years ago

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.

tuckerpo2• 3 years ago

It seems there's a sense of malaise falling over everything and everyone in the USA. People at large simply cannot be bothered to care about anything, including torque specs for freakin' AIRLINERS

spike021• 3 years ago

I know of a pretty famous car tuner in the US (I won't get too specific for various reasons) and despite most people in my community going to him for service over the years, multiple people have come out and proved he rarely if ever torques anything to spec. For the longest time he even allowed customers to watch in the shop space as he worked on their cars and he'd hand-torque many things that the car manual was very clear needed to be specifically torqued for safety and operational reasons.

The fact that people would share this and it didn't curb the amount of business and referrals he got just proved to me what you've said for the longest time.

People don't like to be troubled with details and they'd rather be ignorant of them.

vidanay3• 3 years ago

Probably one of those guys that says "click!" whenever they tighten a bolt.

_ea1k2• 3 years ago

I've noticed the same with electrical work. How many use torque screwdrivers, even when dealing with high load appliances (eg, a 50 amp EVSE)?

GenerWork• 3 years ago

Sounds like Hennessey.

fidotron• 3 years ago

It is even worse than that: those that don’t care will make life intolerable for those that do until they give up trying to help and go away.

You would definitely hope aerospace assembly would be immune to this widespread phenomenon though.

tuckerpo2• 3 years ago

German torque specs: "gutentight!"

Scoundreller7• 3 years ago

My beef is that torque specs are for factory assembly. If you’re using new parts, sure, but once they’re old/re-used parts with some corrosion due to dissimilar metals, age or salt belt, you’re flying blind and probably undertorquing if going by the book.

Given the amount of (soft) aluminum on aircraft, (737 is 80% aluminum), it would be insane to not precisely consider torque.

Steel on steel is more forgiving.

kube-system9• 3 years ago

When I was in high school I helped a lot of my friends fix issues caused by quick tire and lube shops. Lots of snapped, stripped, and rounded fasteners.

jmoss20• 3 years ago

I imagine at least part of this is that specs (and documentation generally) just suck now. It's nigh impossible to sort out which bits are CYA legalese, and which bits are "no, actually, do this or else <terrible outcome>".

That obviously isn't the problem with airplane manufacturing, and maybe not for car mechanics either. But it's totally endemic in the consumer world.

"Do not operate while driving" on car HUDs. "Do not consume if pregnant" on perfectly safe OTC medications. "Do not continue to ride after a crash" on bike frames.

It's not surprising most of this is just ignored now -- there's no information content. The documentation is nothing more than a list of things for which the manufacturer would like not to be liable, and the marginal cost of adding to that list is ~0. It will grow until we run out of room in the manual / space on the packaging.

"Store between 68 and 75 F." Or what? Is that a "must follow or else death", or a "it may reduce efficacy 0.5%" or a "we've never run a sufficiently powerful study under any other conditions, but there's no theoretical reason it should matter"? It matters quite a bit to me which!

I don't see how we can hope to have good-faith communication under such a heavy threat of litigation. I would not be surprised if /that/ turns out to be relevant to the Boeing issue, even if the rest is unrelated.

Sparkyte2• 3 years ago

Culture problem as we hire people of a generation who were not educated or engrained with responsibility they avoid doing the right thing and this happens.

agubelu• 3 years ago

Yes, because no catastrophic defects have been present in airliners in the past 50 years.

bigbillheck• 3 years ago

The only cultural problem is in management.

terminous• 3 years ago

Get this generationalist BS out of here. It isn't supported by the facts. Airline safety has improved with each generation. There were many more plane crashes in the 1970s-1980s when boomers were in their prime. Five times as many!

fulladder4• 3 years ago

I don't think it's generational per se, but I've noticed a declining level of concern for safety in product design compared to even like 20 years ago. I think people got used to the idea that everything is generally very safe and now there's less of an emphasis, so given enough time we'll start seeing dangerous products again and the cycle will start anew.

plagiarist6• 3 years ago

I agree. We need way younger CEOs (and legislators!). This current crop is perfectly fine rushing QA to ship defective products as long as it lines their own pockets. In industries where failures won't directly kill people they actually plan the obsolescence to happen.

Leadership from a more environmentally-conscious and empathetic Gen Z would definitely have safer products that last longer.

jasode2• 3 years ago

People at large simply cannot be bothered to care about anything, including torque specs for freakin' AIRLINERS

It may have not been operator error with the torque wrench. Maybe the torque wrench itself was miscalibrated. Maybe the bolt had a flaw in the metal. It seems too early to make conclusions.

An example of flawed bolts on aircraft in an excerpt from https://www.sciencedirect.com/science/article/pii/S136970210...:

A bolt from an aircraft flap control unit fractured in the threaded region of the shank near the shoulder with the head upon installation after a major service. A metallurgical investigation was carried out to identify the cause of failure. The bolt was manufactured from cadmium-plated, high-strength steel. Material checks carried out on the bolt showed that it conformed to the required specification and was found to have an approximate ultimate tensile strength of 1380 MPa.

The fracture surface of the failed bolt was examined using SEM to identify the mode of fracture and determine if pre-existing defects were present that could account for the unexpected failure. The fracture surface exhibited two distinct modes of failure. [...]

The embrittlement in this case was attributed to the cadmium plating, which is applied to the bolts to provide corrosion protection to the steel. Hydrogen is evolved during the plating process, which becomes absorbed by the steel. The cadmium plating acts as a barrier to hydrogen diffusion at ambient temperature so that the hydrogen becomes ‘trapped’ in the steel. In high strength steels (>1100 MPa) this leads to embrittlement. To overcome this problem, high strength steel fasteners, which have been cadmium-plated, are baked at 175–205°C for 24 hours to allow hydrogen to diffuse through the cadmium. In this case, failure of the bolts was caused by insufficient baking after plating, which gave rise to hydrogen embrittlement.

bob1029• 3 years ago

It seems too early to make conclusions.

In this specific case, I would agree.

I share much of the sentiment of the OP, but I wonder if it is simply my perspective changing as I take on more and more responsibilities. Maybe things have always kind of been this way.

I would be hesitant to say it's all going to hell in a handbasket because that tends to be one of those self-fulfiling prophecies. I prefer to look at things as "challenging, but workable".

thinkingtoilet• 3 years ago

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 rail ecosystem is experiencing the same issues for the same reason.

leetrout2• 3 years ago

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.

nostromo• 3 years ago

You're catastrophizing a bit. This isn't an America problem it's a Boeing problem.

American air travel is safer than it's ever been. Going years without a single fatality is now the norm, not an exception. The airlines are well run and do care deeply about safety. The regulators aren't perfect but generally do a good job. The NTSB is world-class.

Boeing will continue to lose marketshare to Airbus and feel some pain which is appropriate. Eventually they'll get their act together or they will continue to suffer real consequences.

sschueller• 3 years ago

Working conditions in the USA have come to a point where many don't care because the company doesn't care about them. People are fired at will after working for 20+ years with zero shits given. There is zero loyalty and in return workers just don't care either.

There are only so many checks and balances you can build in until this situation will catch up with you.

Doesn't amazon have such a huge turn over that they are running out of possible candidate to replace those workers?

Being pushed to deliver more and more packages in shorter time or inspect train cars in less time then required why would one care if a packages gets tossed or a rail car is not properly inspected?

In most jobs the only consequence is to be fired which is already possible for no reason what so ever in many states.

jskrablin• 3 years ago

Or use a few drops of threadlocker...

0max• 3 years ago

Sagaar from Breaking Points felt the same way in his monologue today.

Nextgrid• 3 years ago

I commented on another thread[1] but I feel like it would apply here:

My theory is that this is not limited to Boeing or even aircraft design, it's a much deeper and systemic problem affecting all kinds of fields. We've had a lot of industrial accidents lately.
When aircraft manufacturing was an emerging industry there were tons of undocumented safety margins and "slack" in the design and production pipeline. Over time, the beancounters start optimizing stuff, so these undocumented safety margins are eroded in the name of efficiency/profit (and sometimes even documented safety margins too).
Furthermore, workers back in the day had a much better life when it comes to purchasing power (especially when it comes to property), and so could actually "give more fucks" about the job than they do now which is a compounding factor. You used to get a lot of implicit quality assurance back then which you don't get now.
We've now reached a stage where these undocumented safety margins have been eroded enough that it actually starts to cause issues, and the safeguards that are supposed to catch them aren't good enough, either due to 1) they've never been good enough but just weren't really needed before or 2) they too have been eroded in the same way for the same reason.

[1] https://news.ycombinator.com/item?id=38896457

fzeroracer• 3 years ago

The 'malaise' is the rot coming from uncurbed late-stage capitalism. Just about every single company only cares about short-term forecasts which leads to enshittification because there is no long-term planning or allowance for things like quality control.

Privately-owned companies or worker-owned companies are more resilient to this problem because the nature of their existence means a stronger focus on long term goals. Though there are still issues with publicly owned companies exerting enough influence to acquire and subsequently destroy private companies. For example, Rite-Aid acquiring Bartell Drugs then going bankrupt and proceeding to shutter most Bartell Drug stores leaving Seattle with a deficit of pharmacies.

pixl973• 3 years ago

“Show me the incentive and I will show you the outcome.”

Welcome to the outcome. When companies look at employees and employee training as an expense, and when the only way to improve your salary is to go to a new company, expect to see these companies to be hollowed out shells of untrained people.

chatmasta2• 3 years ago

This is reassuring news to me, as someone who has opted for Airbus over Boeing (and even paid extra for it) whenever given the choice since the first 737-MAX crashes in 2017.

WheatMillington3• 3 years ago

How is this reassuring?! Are you sure you don't mean "vindicating" or similar? Hard to understand how anyone could feel reassured by this.

chatmasta2• 3 years ago

It's "reassuring" in the sense that I'm reassured I've been making the right decision... but yeah, "vindicating" is probably a more appropriate choice of word :)

thsksbd6• 3 years ago

Id feel mostly vindicated (which is worse - no one likes that guy), but also reassured. Reassured that I'm not crazy!

The decision OP took might have been extreme and costly (time wise and effort mostly). People around him might have lightly whispered to him to be reasonable, or "trust the experts". This wears on you eventually and you start to doubt your own reasonableness.

Boeing starts leaving bolts unfastened and all of a sudden you remember the almost weekly stream of pre-pandemic HN articles with new material on Boeing's fall from excellence.

Boeing's marketing dept. was capitalizing that everyone had forgotten about the MAX. The few of us who remembered it maybe weirdos, but we're nut nuts!

sersi• 3 years ago

I've tried doing this too but unfortunately still ended up on some 737 max due to airplane change after I booked the ticket.

fidelio93• 3 years ago

Could AI help firms like Boeing perform more robust and automated safety checks? I'm curious about how much an issue like this can be chalked up to human error vs. poor, semi-automated QA.

bell-cot2• 3 years ago

GIGO

pc86• 3 years ago

Oh nice this is the first time I've seen the AI equivalent of "Bitcoin fixes this" in the wild.

consumer4515• 3 years ago

This is hilarious, but I think we might be being a bit unfair.

Why couldn't you use something a camera on eyeglasses while doing the work correctly to fine tune a multimodal model, and then infer to a user wearing the same glasses? Audio reply saying "nope, try again."

You would need multiple frames per second, so not today, but not that far into the future, right?

edit: Zero-shot, I just took photos of me "fixing things" around the house, and here is what ChatGPT told me. It does not suck. Do this with fine tuning, many frames per second, and what am I missing?

https://imgur.com/a/H1eSShH

https://imgur.com/a/YXxz8uL

sp527• 3 years ago

Found the Boeing executive.

queuebert2• 3 years ago

Tech L7 who can only program Python but thinks they could be the next Boeing CEO.

Bluescreenbuddy• 3 years ago

Go outside.

_ea1k2• 3 years ago

Neural networks for quality assessment aren't necessarily unheard of. I'm not sure how they'd be using them in this case, though?

Maybe something like a camera monitoring that they are using the correct tool at various parts of assembly? But I'm not sure how feasible this would be at airplane levels of volume.

I bet it'll be common in car assembly at some point, though.

molave2• 3 years ago

It still requires a human to be sometimes skeptical of the AI's results.

swagmoney1606• 3 years ago

lmaooooo

raverbashing• 3 years ago

It is not so clear if the loose bolts are on the door or if they're the bolts that attach the door to the frame. Also given that the door that fell was just found in one piece this makes me suspect the latter

But regardless, not looking good for Boeing

(*door but of course it's more a plug than a real door, just using the term for ease of understanding)

Edit: https://twitter.com/ByERussell/status/1744460136855294106?t=...

jasode2• 3 years ago

I found it interesting that Boeing did proactively tell airlines to inspect 737 MAXs for a possible loose bolt in a different part of the plane (rudder section) at least 8 days before the January 5th event. Example story: https://www.reuters.com/business/aerospace-defense/boeing-ur...

Unfortunately, Boeing did not know they had other issues with the plug door bolts.

nolok4• 3 years ago

Imagine the quality of the manufacturing and QA / final inspection to have that kind of issue.

ethbr111• 3 years ago

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.

AdrianB12• 3 years ago

Nope. It is most probably caused by operational stress - rudder assembly is moving, fuselage is also working (compression and decompression cycles on take off and landing, thermal expansion and compression). I bet they don't just put red Loctite on it to keep it from getting loose. My bet is design flaws, not manufacturing or QA.

EDIT: I saw the pictures of bolts with pins and bolts without pins. The ones with pins cannot get loose, the others can. Let's see what happened.

justinclift• 3 years ago

Maybe an inadequate torque specification for the bolt tightening?

garyfirestorm• 3 years ago

Bolts are most likely tightened with a torque wrench or a gun that is set to a torque spec. Over tightening a bolt is as bad as a loose bolt. I speculate these passed QA from Boeing because they might have been correctly torqued to the spec. What happens in field is hard to understand. One possibility is vicinity to the engine can cause extreme vibrations, these can make them loose. Other possibility is the maintenance side of things - maybe a badly calibrated torque wrench could be the reason. Mechanical systems are not inherently immutable.

onlyrealcuzzo• 3 years ago

It's a QA process better than almost every other industry in the world...

Sure, it failed, and it isn't perfect.

But planes have had a long track record of being absurdly safe.

MilStdJunkie• 3 years ago

Given everything I've seen so far, I'd bet good money that what happened here was miscommunication between Spirit and Boeing. Spirit started out locking down the plug, then Boeing asked them to just loosely attach it[1] so Boeing could yank the plug for interior/wiring/AC/paint, then someone at Boeing forgot about the "loosely". So now, they get in a hurry (maybe the AC/interior didn't need any access to work on, which makes sense for this MAX variant, it wouldn't need as many hatches to pull wire) and it went down the Renton line as if the plug was fully installed. It's enough to pass high blow inspection and other inspections, but then over time that "shipment config" attachment vibrated out, and pop goes the plug.

Almost certainly systemic issue though, so that sucks. Sucks real bad.

They need to get a Tiger Team or whatever together to look at everything with a shipment config, and make sure those "ship kits" don't leak into the real actual airplane configuration. This is . . ok, this is really manufacturing 101 stuff, but well, things happen.

I'm in the industry, but haven't touched the MAX, so take this with a grain of salt.

[1] Basically a "shipping" or train configuration

AdrianB12• 3 years ago

They are not related. Probably different types of bolts, for sure different stress types. Rudder assembly is a moving part, these false door panels are not.

MBCook• 3 years ago

I think the point is there were at least two sets of loose bolts at the same time.

akira2501• 3 years ago

these false door panels are not.

It's not a control surface, but it is a "moving part." That's what's baffling to me, that they spent a lot of effort building this hinge and pin roller system, and designed the door to hinge open up to 15 degrees.

It makes me wonder if there's maintenance procedures that at some point would require the operation of that door to successfully complete. Otherwise, the mechanism itself seems so incredibly overwrought, with lots of additional bolts, castle nuts, retaining pins, and even sprung hinges at the bottom.

Does anyone know why this "plug-type non-plug door" is built this way?

mihaaly2• 3 years ago

I recall a running joke from my childhood - from a former communist East European counry - about a certain car saying you should finish the assembly at home after purchase, tightening the screws before first use. Despite being a famously poor quality car - even in the sloppy East European practices - that supposed to be a joke not to follow suit!

otikik• 3 years ago

That’s “testing in production”, but beast-sized.

nritchie• 3 years ago

Makes you wonder if there was malice involved?

dylan6042• 3 years ago

My grandfather worked for Braniff as a mechanic, and I've heard stories where very strange things would happen that definitely gave merit to some sort of sabotage being a likely explanation. From very specialized tools would be missing not from just one bay, but from all of the bays to other issues that would cause regular maintenance from being able to be completed in a timely turn causing more and more planes to be taken out of service. Lots of things went wrong with that airline, but some of the things just makes you scratch your chin in wonder if it might not be possible.

flohofwoe• 3 years ago

https://en.wikipedia.org/wiki/Hanlon%27s_razor

bahmboo• 3 years ago

I really doubt it is but important to keep in mind that foreign governments running active espionage campaigns against Boeing. The French have dozens of agents. This is from a conversation I had with a person who works in a large counter espionage group at Boeing. This was corporate espionage not defense but I'm sure there's a group for that.

adrian_b3• 3 years ago

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 they did not apply the correct torque to the bolts.

It is extremely surprising if such trivial errors can happen during the assembly of an aircraft.

lokar2• 3 years ago

Or the lock wire was left off or done incorrectly

someguydave• 3 years ago

Aren’t there multiple signoffs & inspections to see if the lock wire was being done correctly?

zokier• 3 years ago

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

rpeden2• 3 years ago

The same part was used on the 737-900 for quite a while and didn't (as far as we've heard, at least) have any similar issues there.

dralley• 3 years ago

And you seem to be assuming that the problem is in the design and not the assembly...

The latter seems more likely.

adrian_b3• 3 years ago

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.

pengaru• 3 years ago

The torque or fastener spec could just be wrong in the face of unforeseen resonance or some other in-flight oddity cumulatively loosening the bolts.

I wouldn't be so certain it's installation error or mfr defect of the fasteners...

Someone• 3 years ago

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.

Or the ‘correct’ assembly instructions weren’t actually correct, or the design isn’t good enough (e.g. it uses too few bolts, or didn’t check the strength of the bolts when they get cold), or the bolts were of the correct material, but designed too thin, etc.

johnwalkr5• 3 years ago

There's at least 1 million root causes of the incident and while I have my own predictions, this industry is a great example of checking all possibilities before jumping to "2 possible causes".

It's really unlikely that washers are a root cause (spring/split washers are useless and are definitely not used for this type of apllication). "Correct torque" is not trivial to determine and maybe it was calculated right or wrong based on right or wrong materials/conditions or maybe conditions were changed or maybe...

I am 99.9% sure a procedure was followed and a torque or other measurement applied and was documented. This is probably not a trivial error but a cascading failure in design and/or documention and/or integration.

ranting-moth• 3 years ago

You should contact Boeing with that information, I'm sure they'll find it invaluable.

queuebert2• 3 years ago

I've seen on Toyotas and also at Universal Studios bolts on rides are marked with paint presumably to indicate that the nut hasn't backed out.

Are airliners marked in this way? Is checking the bolts simply a visual inspection, or do the inspectors need to get out a torque wrench?

hef198989• 3 years ago

Workers are trained and qualified to sign of on their work. Some work is double checked by a co-worker. Some is again checked by QA. FAL work, and loose bolts falling under FOD absolutely, are checked by QA. Or at least should be.

No idea how this can happen, Boeing really has to get its shit together.

lb1lf• 3 years ago

This is SOP in manufacturing to indicate that a bolt has been torqued to whatever torque specified in the assembly drawing; as an added bonus, if the mark is applied properly, you can also tell at a glance whether the bolt has worked itself loose.

chippiewill3• 3 years ago

Unlike on a rollercoaster, these bolts are hidden within the fuselage behind the cabin panelling so a regular visual inspection to see if they've been loosening wouldn't be practical. During assembly the bolts should have been torqued and then checked and the bolts would only be reinspected when the panelling is removed after 3 years or so.

adamweld• 3 years ago

Yes aircraft fasteners are often torque marked, and almost all safety critical fasteners have an additional preload locking mechanism. Often these fasteners use mechanical locking features such as cotter pins, safety wire, or safety cable.

kube-system9• 3 years ago

Even better, safety critical bolts on these doors are (supposed to be, at least) pinned.

https://www.youtube.com/watch?v=maLBGFYl9_o&t=523s

phkahler5• 3 years ago

Even on light aircraft some bolts will have a safety wire through the head to prevent it from turning. You might even see these on bolts holding the propeller on.

Juicyy• 3 years ago

common practice in manufacturing to use a paint pen on bolts in assembly lines to check and make sure nothing is backing out aftre maintenance/repair.

quickthrowman• 3 years ago

I've seen on Toyotas and also at Universal Studios bolts on rides are marked with paint presumably to indicate that the nut hasn't backed out.

This is also standard procedure for electrical maintenance inside distribution equipment. Every lug/termination is torqued to spec and then marked to indicate it has been torqued down. This should be done regularly to prevent any loose terminations from causing an arc flash.

blindriver• 3 years ago

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?

pluc• 3 years ago

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

intrasight2• 3 years ago

A guy holding an inspection report issue

myself2482• 3 years ago

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 the processes to catch ever more.

jkqwzsoo• 3 years ago

Keep seeing this take (just an installation issue), over and over and over again.

I think it's much worse than a design flaw.

Even very carefully-engineered systems can have flaws. Engineering flaws, once identified, can be engineered around, managed, or corrected.

I'm much less comfortable with the idea that the assembly plant for these planes could be a random-critical-failure generator based on how the employees handle a torque wrench.

barryrandall2• 3 years ago

It calls into question Boeing's entire portfolio because it's all a product of the same management culture.

SoftTalker3• 3 years ago

It's a door design that dates back to the 707.

chippiewill3• 3 years ago

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

phkahler5• 3 years ago

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

nolok4• 3 years ago

Boeing already warned airlines on january 5 (before the door issue) to check for lose bolts in a different section of the plane (the rudder). This is not a door plug issue.

avalys• 3 years ago

It's not really about the door plug per se, it's about how Boeing's entire manufacturing, design and QA process could allow such an elementary mistake to escape notice in the first place.

If they got this wrong, what other bolts didn't they tighten properly? This question is especially relevant since just a few weeks ago, Boeing issued an airworthiness directive about loose bolts in the rudder system.

In any reasonable aerospace organization, the discovery of a systematic problem with the rudder system assembly should have prompted an audit of other processes. Why did that audit not uncover this issue with the plug door?

Presumably, the answer is that Boeing's processes are so incomplete or and/or unreliable so that, even when being given a hint at what kind of a problem to look for, they can't find other instances of the same problem themselves.

It raises the question of what other systems on the plane have problems, and whether Boeing is even capable of confidently answering this question at this point, or whether we just have to wait and see what other parts start falling off.

tomohawk• 3 years ago

Industrial sabotage? Grievance sabotage? Quality control?

Hopefully they can track down the cause.

barryrandall2• 3 years ago

Metrics that don't give employees enough time to accurately complete their tasks? Management whose first and last priorities are quarterly financial projections? Transitioning from external oversight to self-reporting?

I do hope they can track down the cause, whatever it might be.

pierotofy• 3 years ago

It might be another fault due to the cultural shift that's been happening at Boeing: https://www.npr.org/2019/10/26/773675393/boeings-cultural-sh...

Safety and quality were taking a second seat to schedule and cost.

blibble• 3 years ago

"the most scrutinised transport aircraft in history"

7e• 3 years ago

Not reassuring.

nwallin• 3 years ago

Not reassuring indeed.

"most scrutinized world leader in history"

ActionHank• 3 years ago

Well yeah, keep making things that break or cause issues and people will have to scrutinise more and more.

phkahler5• 3 years ago

737 != 737 Max.

fshbbdssbbgdd2• 3 years ago

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 are loose, and there’s not meant to be a pin on those.

I’m curious how the decision is made whether to include that pin in the design. Did they idiot-proof the maintenance of the plug, but not the initial installation?

fshbbdssbbgdd2• 3 years ago

More rampant speculation!

Some quotes from this article: https://www.reuters.com/business/aerospace-defense/spirit-ae...

As part of the production process, Spirit builds fuselages for 737s and sends them by train with the special door assembly “semi-rigged,” one of the people said.
“They are fitted but not completed," the person said.
At its Renton, Washington, plant, Boeing typically removes the pop-out, or non-functioning, door and uses the gap to load interiors. Then, the part is put back and the installation in completed. Finally, the hull is pressurized to 150% to make sure everything is working correctly, the person said.

I can imagine a diffusion of responsibility as to whose job it is supposed to be to tighten those hinge bolts. Spirit is installing the plug in a “semi-rigged” state. Boeing is removing the plug to load the interior, then reinstalling it. I’d hazard a guess that Boeing is not removing the hinges, because the plug can be removed without doing so. What if, when reinstalling the plug, Boeing workers just redo the stuff they removed? They tighten the vertical movement arrestor bolt, put the pin through it, and believe they have done their job? If they never messed with those other hinge bolts, they don’t bother tightening them?

thehappypm• 3 years ago

There’s no way that this is what happened. They’re not building IKEA furniture, everything is tightly check-listed.

avidphantasm2• 3 years ago

I’m no MBA or aerospace engineer, but why sub-contract the fuselage? I get subbing engines, since engine designs can be used on/adapted to other (possibly non-Boeing) airframes, hence opening up economies of scale, etc. But the fuselage is most of the plane by mass and integral to the design of everything else. If you don’t like making fuselages, maybe you should get out of the aircraft business. Was this just a union-busting thing?

1970-01-01• 3 years ago

The castle nut design requires the use of a cotter or other locking pin.

https://en.wikipedia.org/wiki/Castellated_nut

https://en.wikipedia.org/wiki/Positive_locking_device

Rapzid4• 3 years ago

"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, under shear, work their way out completely? And isn't the lift spring forcing the top pins into the upper part of the track? On top of that the curve of the track appears to be such that outward force on the door would actually cause the pins to go into the upper part of the track.

IDK, seems like there is something else going on. Different bolts maybe.

pests2• 3 years ago

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.

userbinator• 3 years ago

I'm not an aerospace engineer, but it seems those hinge bolts might be better replaced with rivets --- if the hinge isn't frequently removed from the door.

outside12343• 3 years ago

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

jlmorton• 3 years ago

Always refactor

kube-system9• 3 years ago

Bolts can be loosened, or fail to be tightened on any aircraft. I suspect this may be a problem with people and/or procedure.

RomanPushkin• 3 years ago

The question is not about bolts, but more about what else is hidden there, what else is mechanically neglected that's waiting in there to take lives

adrian_b3• 3 years ago

Since the aircraft with the incident was extremely new, it is pretty certain that the bolts have not been properly assembled at Boeing, so the problem is with their assembly procedures.

thatjoeoverthr• 3 years ago

If it’s built so sloppily, will you manage to think of literally every mistake they might have made?

infotainment2• 3 years ago

Agreed — while we’re at it, let’s break Boeing up into multiple firms. It has been “too big to fail” for too long.

jerlam• 3 years ago

Not sure that would help - the Boeing subcontractor that likely played a role in the defective parts, Spirit Aero, was previously part of Boeing and spun off in 2005.

bastardoperator2• 3 years ago

I've said it here before, but working with Boeing, every project might as well be a different company.

Yizahi• 3 years ago

All top 5 defense contractors preferably. And do the same in the EU too. Monopoly (effectively) clearly failed western defense efforts as the war shows now.

KptMarchewa• 3 years ago

Force it to develop actually new airplane, not rely on grandfathered type license from 60 years ago.

selectodude3• 3 years ago

They keep trying to do that. This mess of a plane is care of Southwest and Ryanair who wanted a re-engined 737, period.

_jal• 3 years ago

I don't know that they could. We're talking about Boeing, they're the sort of MBA hive that's embarrassed to have to employ engineers.

Scoundreller7• 3 years ago

I wonder what automotive designs would look like if we allowed that kind of grandfathering. Or maybe we do but people keep wanting new car designs?

ramesh312• 3 years ago

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.

epicureanideal• 3 years ago

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

lamontcg• 3 years ago

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.

The MD merger that led to the shift of Boeing management culture was due to the government intervening and forcing a marriage between the two companies because MD was too important for vital defense interests.

trebligdivad• 3 years ago

https://www.youtube.com/watch?v=maLBGFYl9_o is a good video explaining how the bolts/doors etc are supposed to go together.

squirtle24• 3 years ago

Very interesting video that shows a clear picture of how the plug is held in place. Some interesting spots in the video, 8:44 shows how the upper two locking bolts lock the roller pins into the upper door tracks, and 10:00 show the lower two locking bolts onto the sliding hinge posts. 13:10 shows how the door blew cleanly off, with very little damage to the roller pins and lower hinge posts. Some comments say the same plug have been used on the 737-900 which didn't have this issue.

My armchair speculative guess: there are only 4 bolts effectively holding the door onto the roller pins and lower hinges. Somehow I don't think it's a simple case of someone forgetting to tighten the bolts; since they're using castle nuts, forgetting to torque them down would leave behind extra cotter pins. Those bolts look positively tiny, probably no more than M12 diameter, and are subject to intense shearing forces. In the case of the upper roller pin with locking bolt, they are effectively two cylinders perpendicular and on top of each other, which causes extreme compressive forces to be concentrated on one tiny spot on the bolt. My guess is they cheaped out and switched to an inappropriate/softer bolt, which sheared and/or corroded. If one shears, the load quickly spreads to the remaining 3 bolts which all also shear off. This theory would still jive with OPs article about UA; "loose bolts" may not necessarily mean "untightened nuts and bad QA", but rather, signs that the locking bolts are all beginning to bend or shear.

emchammer• 3 years ago

Shear forces on four bolts, isn't that the same thing that caused the disaster in that hotel with the suspended walkway in the 1980s? With more than a hundred deaths. Is this not a basic case in engineering school, like THERAC-25? Not a licensed PE.

yuliyp• 3 years ago

Most of the pressure of the door should be supported by the stop pads, rather than the bolts. The force on the bolts should generally be from vibrations, not from pressure differential pushing the door out.

ooboe2• 3 years ago

The 4 bolts are there to restrain vertical motion of the door which I presume would not involve large forces. They are meant to keep the door on the 4 cylindrical posts and 12 stop pads and it is those posts and pads that take the pressure differential forces on the door and keep it from blowing out. They are way beefier than the bolts and I believe they are still intact on the accident plane.

johnwalkr5• 3 years ago

Oh wow. I made another comment about how important tension in fasteners is, to provide a clamping load and therefore friction between two faces. I was thinking that there must have been a process failure. Fasteners often shear off if there is not enough tension and therefore friction. But in this case it looks like there is not any clamping load between parts for at least some of the fasteners, so those fasteners basically act only as pins. There are other "stop pad" parts that constrain movement of the plug but as far as I can tell they must be compliant/flexible parts. The video mentions "roller pins" which for a door would be used with a cam mechanism. I think that stop pads plus roller pins/door/cam mechanism holds the door securely, but stop pads plus plug/pins does not.

On paper all 6 degrees of freedom may be constrained with the plug but in principle compliant pads may allow shear forces and/or rattling on the fasteners and they eventually fail.

I will eat my hat if the eventual required solution doesn't involve some kind of mating cup/cone or wedge shaped parts to more positively constrain the plug.

dmix• 3 years ago

The recurring question is that it was only 2 months old so likely had those bolts underneath the roller thing was not fastened properly or the whole concept is flawed and this one simply had some bad turbulence/rough landings which created the perfect pressure on them.

bad_alloc• 3 years ago

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

aledalgrande5• 3 years ago

The A320neo family has had four ground fatalities and one hull loss accident as of November 2022.

https://en.wikipedia.org/wiki/Airbus_A320neo_family

A320neo is the direct competitor to the MAX. So yeah, they're doing pretty well.

jacquesm9• 3 years ago

And that hull loss wasn't on account of a faulty design, assembly or process issues.

Crew and passengers were unharmed after a collision with a firetruck crossing the runway while the aircraft was doing its take-off roll.

disiplus• 3 years ago

i'm not sure are you being sarcastic, there were no fatalities on the airplane. but once motorcycle and another time a firetruck crashed with the plane and people died.

notahacker3• 3 years ago

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...

aledalgrande5• 3 years ago

So Airbus has fault for a paint job? While they should do better, that sounds a lot safer than airplanes losing pieces or crashing down to me.

You'll hear more about Boeing than the rest of the industry put together because this is HN...

That's not it.

rconti• 3 years ago

So, about that Max 10 on which you were hoping to get fast-track approval...

0cf8612b2e1e2• 3 years ago

Airbus must be having a fantastic week.

masklinn• 3 years ago

Probably gives them some succor given the engine issues they’ve been having.

toomuchtodo• 3 years ago

Airbus is sold out on A320s until the 2030s already.

https://www.bloomberg.com/opinion/articles/2024-01-08/alaska...

xtracto2• 3 years ago

Airlines should stop buying Boeing airplanes. At this point they are catastrophes waiting to happen.

Fortunately, most airlines in my country use Airbus planes.

dataflow3• 3 years ago

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

Kluggy• 3 years ago

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

dataflow3• 3 years ago

This required a full disassembly to be noticed?

janice1999• 3 years ago

They do disassemble the entire plane for heavy maintenance checks every 6-12 years. The MAX 9 has been in operation for just a few weeks though...

jupp0r• 3 years ago

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!

gnopgnip• 3 years ago

Shouldn't the bolts be safety wired after being torqued?

exabrial3• 3 years ago

Precisely... everyone other "expert" on HN is asking the wrong questions

rabuse• 3 years ago

Hot take, but I'll bet this will become more epidemic as companies hire more for quotas rather than merit like they used to.

krisoft• 3 years ago

Is this the first time these planes have been inspected?

Most likely weren't checked since the planes left the factory yes.

To quote from: https://theaircurrent.com/feed/dispatches/united-finds-loose...

"The five aircraft were delivered to United between November 2022 and September 2023, according to ch-aviation, and would likely not have been through a heavy maintenance C check that occurs every 4,000 to 6,000 hours or two to three years."

nolok4• 3 years ago

I think parent meant inspected by the factory before sending it to the airline, not the regular maintenance check from the airline.

dataflow3• 3 years ago

I read that too, but it says they have 79 of this aircraft. Were all of them new? Or did only the new ones have this issue?

wnevets• 3 years ago

but shareholders got rich and that's really what is important.

Boeing Co. (BA.N) directors authorized a record US$20 billion share buyback program and boosted the company’s dividend 20 per cent -- a sign the planemaker doesn’t intend to stop showering cash on investors any time soon.[1]

[1] https://www.bnnbloomberg.ca/boeing-sets-new-20-billion-buyba...

rmbyrro• 3 years ago

Is the aircraft industry also adopting the "move fast, break things" now?

molave2• 3 years ago

Literally yes (at least for Boeing). Pray Airbus doesn't do the same.

avgDev• 3 years ago

Flying in this plane in a few days......a bit uneasy to be honest.

outside12343• 3 years ago

I think they are grounded - so it will be something else

mynameisnoone4• 3 years ago

You think. The bigger problem is the engineering and manufacturing processes that went into the 737 MAX is garbage. There will be no end to the problems because it's trying to nail mud to the wall. People who choose to continue flying on them are like people who don't wear seat belts: they know it's dangerous but refuse to act in their own interest of self-preservation.

exabrial3• 3 years ago

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?

anderber• 3 years ago

If the regulators don't require the extra exit door, then the airlines would rather put in an extra row for more profits. The extra safety door is only needed depending on seating configuration.

Gibbon1• 3 years ago

And this just blew every bit of profit you could make off those extra seats.

exabrial3• 3 years ago

That's what I figured.

benhurmarcel• 3 years ago

Less cost and weight, and more rows. Only advantages there.

Aqueous• 3 years ago

Literally just flew on a United Airlines 737 MAX 9 one week ago. It seems like the craft I flew on has probably been grounded in the week since. I noticed that we were flying on a MAX before boarding and nearly asked to switch flights, but consoled myself that I was being irrational and that the planes were almost certainly fine now. Guess my confidence was misplaced.

bobsomers2• 3 years ago

FWIW, it's only the Max 9s which have this issue. The Max 7s and 8s don't have an exit in that location (too few seats) and the Max 10s require an exit door to be installed in that location, not the door plug.

It's only the Max 9s that have the option of the door plug, if the installed seat count is below the threshold where an additional exit is required.

ajb257• 3 years ago

I think the concern is more the attitude that allowed this to happen, despite all the issues Boeing has had.

alistairSH2• 3 years ago

7s and 10s aren’t out in the wild yet. Only 8s and 9s.

boyter• 3 years ago

Just had all my connections cancelled. So extra day in San Fran for me which is less than ideal, but probably better than being on the flight if something happens.

It was total bedlam at the airport when I got in this morning however. With almost no flights available to replace the grounded ones.

Another red eye special for me tonight but at least no connections.

tycho-newman• 3 years ago

I mean, you're here now. Plane did its job.

The safety margins on flying machines is really high, so while Boeing really should figure out what the hell is going on, the plane didn't fall out of the sky after a depressurization incident. It failed to a known state (ideally by design!)

loloquwowndueo2• 3 years ago

That it didn’t fall out the sky is largely due to the door blowing off at a lower altitude by some fluke or miracle. Had this happened at cruising altitude we’d be telling a different story.

tharkun__• 3 years ago

What tells you that was by design vs. pure luck?

Given the MCAS thing and other shenanigans Boeing is trying with the MAX certification my bet is on luck.

oooyay• 3 years ago

Kind of non-sequitur, but am I disconnected from reality if at this point I do not want to fly on a Boeing aircraft?

outside12343• 3 years ago

It is really the 737 - not sure what is going on with the MAX design team - but it ain't good

The 787 and 757 seem to have been stable platforms.

maybelsyrup• 3 years ago

I think you're mostly correct but while it's not been as bad as the Max, the 787 has a not-so-short list of controversies, starting with those electrical / battery fires early in the plane's life [1] and going through recently with stray tools, fuselage issues, etc. [2] Not an engineer or a pilot, but like the poster above, I'm a regular person wondering how concerned to be on at least two Boeing platforms these days.

[1] https://en.wikipedia.org/wiki/2013_Boeing_787_Dreamliner_gro...

[2] https://aviationweek.com/air-transport/new-boeing-787-fix-de...

aaronmdjones• 3 years ago

I'm a firm believer that the 777 is the last Good Aircraft that Boeing made.

heads3• 3 years ago

Bolts and machine screws are very interesting. One mistake I, an amateur bike mechanic, made for years was not greasing bolts properly before assembly.

It sounds counterintuitive but without grease a bolt (or machine screw) will bind early with a high torque well before it is correctly tensioned lengthways. The torque is just a proxy for the tension and it is this tension which is needed to fasten your components together as intended.

The grease means that when the torque to turn the bolt reaches the correct value then the bolt is also under the correct tension instead of being because it got stuck in the thread half way.

NegativeLatency2• 3 years ago

I keep a toothbrush covered in grease for just this purpose.

It’s also a magnetic one so I can stick it to stuff and it stays put.

TaylorAlexander2• 3 years ago

I keep a toothbrush covered in grease for just this purpose.

Speaking from personal experience, this is also useful for brushing a robot's teeth.

shmeeed• 3 years ago

Where does one find a magnetic toothbrush?

myself2482• 3 years ago

There are different torque-to-tension equations for lubricated and unlubricated fasteners, of various materials and platings.

WheatMillington3• 3 years ago

Only grease fasteners if specified by the manufacturer, otherwise you're going to apply much higher than specified tension at the same torque value.

Scoundreller7• 3 years ago

I need manufacturers to give "frame spent 3 decades in the salt belt, questionable metal compatibility and won't be taken apart until it breaks again" torque specs.

It's like they think I'm going to take this thing apart and put it back together every year.

j/k, finding torque specs for a decades old steel bike is a lost cause

WalterBright5• 3 years ago

Yes, that's the way aircraft fasteners are put on.

There's another reason to grease them - the grease keeps the water out which prevents corrosion.

In working on my cars, I always use a bit of grease when assembling fasteners. I've never had one come loose, nor have any rusted themselves on.

deelowe3• 3 years ago

A properly designed service manual will specific if the fastener should be lubed. If it doesn't say lube/thread locker should be used, then the fastener should be torqued dry.

loeg2• 3 years ago

In bicycle applications it is common to elide explicit instruction to use grease. Nevertheless it should be used.

johnwalkr5• 3 years ago

It's a complex topic. Depending on the design, lubrication may be required or forbidden. And if it's required, it should normally be on the threads only, under the head is usually forbidden.

And it's very important to understand that in most mechanical design with fasteners, the fasteners provide tension, and friction between 2 faces actually carries the load. Too little tension then fasteners can be sheared off. Too much, then the fasteners may not have remaining strength available for loads that act to add tension to the fasteners.

Using a torque wrench to reach target tension is normally only about +/-30% accurate. Usually design margin allows for this but in very critical applications where margin is not feasible, calibration is done on a sample of the same materials, etc, or a more direct measurement done. More direct measurement can mean hollow fasteners that allow you to measure the amount of stretch, use of ultrasonic measurement to measure stretch, washers with integrated strain gauges, or cleverly designed "tension indicating" washers or fasteners. There are many types so I just those keywords for anyone interested.

I am not saying that this design required such complex methods and sizing these fasteners should not be difficult. There is probably a mistake or lack of control in the assembly process.

jacquesm9• 3 years ago

Lots of good stuff in this comment but I'm confused about the +/- 30% accuracy quote, in my experience it is relatively easy to reach sub 10% accuracy based on comparing different (good quality) torque wrenches against each other and against a calibrated one.

Is there something I am missing here?

talldatethrow2• 3 years ago

Ive been working on cars and motorcycles and everything else other than airplanes for almost 25 years now, from motor swaps to transmission rebuild and custom suspension. The only time I ever use is a torque wrench is on engine internals, or smaller fancy areas into aluminum. Everything else, over the years, you learn by feel.

You pay attention to the size of the bolt, the material it's going into, and it's overall job. Yes you'll mess it up a few times a long the way. Hopefully you're a lot more careful when you see that the cost of making a mistake is a difficult extraction or alteration of some sort. Personally, I think you'll run into bolt/thread failure 10x more from improper insertion, dirty threads, corrosion, and overall entropy than you will from over torquing once you learn a few early lessons.

I've done countless brake jobs, tire rotations, oil changes, spark plugs, valve cover gaskets, shock and bushing changes, without a torque wrench. I've yet to ever had a problem from it after going a little too hard when I was 16 yrs old and learning what bolts and materials can hold what.

ssl-3• 3 years ago

Torque specs only apply to clean and clear threads that are free of corrosion and grease -- unless otherwise-specified.

Threads that are this way do not get stuck half-way.

If the threads are already boogered up for whatever reason, then the torque specification is already wrong: The threads aren't clean, clear, and free of corrosion and grease. This can result in under-tensioned fasteners when using a torque wrench as a guide, since boogered threads (rather obviously) can present an impingement that allows a torque wrench to click off before proper tension is reached.

However, grease is not a magical antidote to this condition.

If the threads (boogered or not) are greased, then the torque spec is also wrong: Greased threads are also not clean and clear, and free of corrosion and grease. This can result in over-tensioned fasteners when using a torque wrench as a guide, since grease is (rather obviously) a lubricant -- allowing things to slide more-freely in a way that doesn't allow a torque wrench to click off until somewhere beyond ideal tension.

---

So what do, then, as a home-gamer with a bicycle or maybe a car in the rust belt (but never an aircraft) full of dissimilar metals that are constantly rotting?

You could perhaps kit up to do the Junker test such as in DIN 65151, and make a study of how different greases affects things. You can even make a career out of publishing your studies.

Or: Just make sure the threads are clean, clear, and dry, and then assemble with an anti-seize paste which does not have lubricating qualities that affect final tension yield. (Permatex makes some, as do others.)

---

(And in aircraft, always do what the engineers say. If the engineers are wrong, then: Stop doing whatever it is that you're doing, and consult them.)

stjohnswarts2• 3 years ago

In some cases (some spark plugs are what I can think of) explicitly tell you NOT to grease them, as that will let you over-torque them and potentially damage threads (aluminum heads, steel plugs). So using grease is not always the recommended procedure.

alistairSH2• 3 years ago

Looks like 4 large bolts with castle nuts and cotter pins hold the plug in place.

Looking at how the plug is configured, you'd have to really screw up for the panel to fall off.

https://m.youtube.com/watch?v=WhfK9jlZK1o

ShakataGaNai• 3 years ago

If it's Boeing, I ain't going.

8bitsrule• 3 years ago

Assuming that it's up to airline's employees (not Boeing) to remove/replace the panel/'plug as needed - and that 'loose bolts' means 'not properly torqued' rather than 'can't be', the logical conclusion is that the problem lies with the airline's employees (not Boeing).

IOW, it's far too early to be speculating about blame.

CamperBob22• 3 years ago

Why would the airline need to remove/replace the plug? It doesn't appear to be the sort of thing that requires maintenance. They would have to remove the interior wall panels to inspect or work with the hardware involved.

In any case the aircraft is only a couple of months old, so it probably hasn't undergone any major work by the airline yet.

Arguably it should have, if the reports of pressurization warning lights are accurate and meaningful. But sadly, I can imagine them looking for a problem, not finding this one due to the need to take the whole plane apart ("Unable to replicate"), and concluding that the warnings were spurious.

splap• 3 years ago

for the history on Boeing's rot and the issues with this plane, this book is great:

Flying Blind: The 737 MAX Tragedy and the Fall of Boeing

mynameisnoone4• 3 years ago

Link?

Also, the rot didn't start with the 737 MAX. The 737 NG has critical problems that went unaddressed that has contributed to multiple fatalities and equipment damage. Here's a documentary about it:

People & Power - On a wing and a prayer (2010) Al Jazeera

https://youtu.be/IaWdEtANi-0

https://www.aljazeera.com/program/people-power/2010/12/15/on...

INGSOCIALITE• 3 years ago

all of this just to eliminate an emergency exit to fit 2 extra fares on each flight

asdff• 3 years ago

Honestly I'm surprised why airlines aren't being designed for the slumlord airliner at this point. its pretty obvious from the haphazard window placement on any airplane that it was built to have more legroom but they slid the seats narrower on the seat rails. USB ports never work and power outlets are bent loose to not hold anything plugged into them. Might as well narrow the windows accordingly and ship the plane without cabin electric to save a few cents on initial cost.

dpkirchner• 3 years ago

And to avoid retraining 737 pilots, I guess.

dphidt• 3 years ago

I am curious why the door plug is not a plug door — that is, a design wherein the desired panel would be installed from the inside and sealed by the differential pressure, like a cabin door. This part looks more similar to cargo door; those usually have to open outward for space, but what is the design constraint for this case?

radu_floricica2• 3 years ago

Yep, that's the top level design mistake. They should be locked passively by the pressure differential.

mynameisnoone4• 3 years ago

Ed Pierson, a former senior manager at the 737 Max factory in Renton, WA, indicated there have been 20 quality/airworthiness issues post-MCAS to date prior to this latest incident that have gone largely unnoticed by the mainstream media.

It's also worth noting that other ex-employees of Boeing have also raised concerns about substandard structural components made by Ducommun and Boeing's own manufacturing processes for the 737 NG (737-600 to -900). There is no way to know which ones are defective because an unknown number of these critical parts were manufactured inconsistently and haphazardly by hand when they were supposed to be CNC'ed and Boeing just slapped them in without much care. The net result is an average Boeing 737 NG is variably structurally weaker than previous models, and prone to fuselage breakup on hard landings, runway overruns, and possibly in-flight during extreme turbulence. Level 2 corrosion on structural components only 8 years old is what happens when nonconforming, trash parts are passed off as "conforming".

Around 2009, the DOJ made a false statement that the NTSB said the NTSB concluded structural components were "not responsible" for AA 331. These were absolute lies drafted by Boeing's lawyer, Mr. Cole, as no conclusion had been yet reached. In a subsequent sworn video statement, the DOJ official admits they spoke Boeing's words largely verbatim.

This is what happens when publicly-traded corporations are run by MBAs who gut a company's core competencies for short-term profits and are allowed to largely regulate themselves as a consequent of regulatory capture and the corrosive influence of elected officials who accept "campaign support" and gold bars.

consumer4515• 3 years ago

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]

rossjudson• 3 years ago

blancolirio is really great at explaining...mishaps. He provides details and an explanation of those details that's accessible. It's the first place I go to "find out what happened" for any kind of air incident.

AdamJacobMuller• 3 years ago

Not just aviation and not just mishaps, but, almoshaps too!

I first started watching his channel during the Oroville dam crisis in 2017 and he had some excellent coverage of that event. He seems to cover "things which interest him" the venn diagram of which which overlaps with mine quite a lot.

mihaaly2• 3 years ago

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

avidphantasm2• 3 years ago

Why don’t they just replace the plugs doors. Those don’t seem to fail.

free20233• 3 years ago

Why are there bolts and machine screws in use in the first place?

The seating configurations for United and Alaska, the 2 major customers for this aircraft, don't require this plug-door feature. Structurally, for these large carriers, the plug door serves only as a fuselage weakness and failure point.

Why don't they just rivet it permanently to the fuselage and make it non-functional? Per the diagrams shown, it's a complex assembly that serves no purpose at all for these carriers.

(Apparently it was used as a cargo door to furnish the interiors, which seems like a trivial use case.)

local_crmdgeon2• 3 years ago

Saves Boeing money by manufacturing 1 frame

free20233• 3 years ago

Yes, certainly. But the carriers could configure it to make it non-functional, since it serves no purpose for them. Or they could spec it as a rivet-it-shut option from Boeing. Just seems crazy to have this big failure point in the fuselage, adding to their maintenance costs, for a thing they don't even use.

arrakeenrevived3• 3 years ago

Aircraft are often sold between airlines, or reconfigured even with the same airline. If United ever wants to reconfigure their 737s to be higher density (which is pretty common), they might need to start using that door as a real emergency exit.

free20233• 3 years ago

Yes I see, that makes good sense. Given the course of events, it's still a fair question from a design standpoint: Can this be engineered with a reversible option to switch it from functional to non-functional, depending on the seat configuration?

It just seems like a lot of complexity and moving parts, for a feature that's not in use.

1-6• 3 years ago

Is union labor shielded from poor QC?

adolph• 3 years ago

Shades of March 2019, below.

(CNN) In a blistering attack on Boeing, the Air Force's top acquisition official said the company has a "severe situation" with flawed inspections of its new KC-46 air refueling tanker aircraft, after trash and industrial tools were found in some planes after they were delivered to the Air Force.

Edit, remove: What is going on in Everett?

booleandilemma2• 3 years ago

Gotta love the "We protect our content to protect our future" pop-up message when you try to copy text from the site.

mikewarot3• 3 years ago

At this point, I believe Boeing needs to suffer the corporate death penalty, because it no longer operates as a net benefit to the public. It needs to be dissolved, and its assets sold off. Criminal charges should be pursued to the maximum support of the law against all of the corporate officers.

Those in the FAA and other oversight agencies who failed to properly oversee them should also be prosecuted.

Failing the above, perhaps it's time to revive an apocryphal custom of the Romans. The engineer of a bridge was required to have his home below it, as a means of enticing them to make sure it was well constructed. We should require that Boeing board members, and their immediate family, only fly in Boeing planes of same variety sold to carry paying passengers.

eYrKEC2• 3 years ago

I agree with Boeing board members flying Boeing, and likely they already do, but have you ever floated beings above the aether in metal machines? Do we not live in the age of magic?

unethical_ban• 3 years ago

I'll be charitable and assume you suggest "assets sold off" includes divisions to support existing planes and infrastructure.

mikewarot3• 3 years ago

Sure, let a more reputable company buy them intact. If there aren't any suitable purchasers, and it's important to national security, then nationalize it.

shermantanktop3• 3 years ago

How do you feel about car makers? They kill a lot of people. Food poisoning, bathtubs, lightning…

I don’t disagree that it appears that Boeing has acted badly here. And I’m frustrated with golden parachutes, out of court settlements, and other ways of evading corporate responsibility. But this is a moment in time, and I think Boeing could redeem itself.

mikewarot3• 3 years ago

I feel that any corporation which goes rogue deserves to be dissolved, and the people who are responsible should be punished.

Serving the public good should be one of the responsibilities of a corporate charter. If we're not collectively better because a corporation exists, it needs to go.

If we grant Corporations rights, they should also have commensurate responsibilities.

someonehere• 3 years ago

Are airlines still saving money by “servicing” their airplanes overseas with cheaper labor like my friend told me a few years ago?

After 9/11 a friend who I’m close with was laid off as well as many other maintenance people. United began the process of moving their plane maintenance people to southeast Asian locations to cut down on labor.

Race to the bottom to save money and now loose bolts?

graton• 3 years ago

They now know "what broke": https://news.ycombinator.com/item?id=38922366

FerretFred• 3 years ago

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

anonfromsomewhe• 3 years ago

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

alexpc2012• 3 years ago

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.

MarkMarine7• 3 years ago

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 wire and installed part.

There is something rotten in Boeing.

RF_Savage• 3 years ago

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.

rvba• 3 years ago

Looks like the installer did their job poorly and the QA rubber stamped it without checking. Are the QAs required to make photos to prove that they did their job? Like those food delivery people.

Alternative is wrong bolts, or sabotage.

But more possible - one lazy QA ghosting.

markdown3• 3 years ago

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.

leptons• 3 years ago

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

lvl102• 3 years ago

[REDACTED]

giardini• 3 years ago

Wby the rush to judgement ("The fish rots from the head."). What was done and not done will be traced and the causes determined with good old engineering and detective work. Responsibility will be revealed and the proper parties punished.

Rushing to judgement merely obscures the true responsibilities.

whatever1• 3 years ago

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).

gregoriol• 3 years ago

Don't they have many ways to prevent bolts from unscrewing? I know at least a few by doing mechanical stuff on motorcycles, and it seems that other planes don't have such problems (at least not within 2 months after the last inspection).

somewhereoutth• 3 years ago

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.

stjohnswarts2• 3 years ago

Did you torque every bolt every time before every flight?

defrost• 3 years ago

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.

MarkMarine7• 3 years ago

Every bolt you could see was checked before every flight yes. Every important bolt you couldn’t see during inspection was torqued, witnessed by QA, secured via safety wire or cotter pin, and secondary torque holding was then inspected by QA.

This thing is obviously not just an interior part, look at the meat in those castings, and it’s obviously safety critical, look at the cotter pins on other bolts. Sounds like it was going to be installed behind interior paneling and not inspected every day. For something like that, every important bolt should be secured by secondary methods, torqued and witnessed installed correctly. This looks like a failure in engineering (not having wire on this bolts), then a profound failure in assembly with multiple people not doing their jobs (not torquing, not witnessing, faking logs), risking the lives of passengers.

If this happened at cruising altitude and speed, people would have died. I can’t find the flight number but I believe 9 people died when a jet lost cabin pressure and a piece of the plane while decompressing during cruising altitude over water.

DANmode2• 3 years ago

signed their life on the line

Clearly this is hyperbole.

MarkMarine7• 3 years ago

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

storf45• 3 years ago

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.

x86x872• 3 years ago

Let me ask this: assuming they did not tighten the bolts correctly and qa didn't check it, what are the odds they keep an accurate paper trail?

radu_floricica2• 3 years ago

Were these plug doors mounted by Boeing themselves? Or under Boeing's aegis, which is the same thing. Or were they sold in a different configuration and an external contractor did the modifications?

wateralien• 3 years ago

I would like Google Flights to be able to filter for aircraft equipment manufacturer.

londons_explore2• 3 years ago

Which 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.

nikanj• 3 years ago

* A lazy/time-pressured worker skips applying threadlocker before assembly

justinjlynn• 3 years ago

Insufficient and negligent quality control systems design permits a single point of failure in manufacturing process specifically designed and funded to prevent such things - calling into question the trustworthiness of the manufacturing process compliance for the entire product line.

arghwhat• 3 years ago

Those are not the only options.

* Improper bolt tensioning process where bolt tension is later unintentionally reduced due to tensioning order.

* Design or material failure where bolt tension post-installation drops more than design allows.

* Miscalibrated or otherwise defective equipment.

* Other failure in manufacturing not caused by the worker, e.g. missed a necessary second or third tensioning pass (different torque or rotation angle) without appropriate failsafes or final validation to discover it.

Bolt tension validation is normally done with an ultra-sonic scan. Torque only provides a rough approximation of the tension at time of installation, and is only suitable where precision is not a requirement.

I suggest https://www.youtube.com/watch?v=XLzTB4KLCxU for those curious about bolts - a very specific, but interesting video.

legacynl4• 3 years ago

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.

londons_explore2• 3 years ago

The mistake was forgetting to tighten them. The offence was faking the torque wrench results to hide the fact you forgot to tighten them.

whywhywhywhy• 3 years ago

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.

DrScientist• 3 years ago

Is 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?

hugh-avherald• 3 years ago

Not just the US economy but the US military and the worldwide aviation sector.

The Europeans would, if it truly came down to the wire, pay quite a lot to keep Boeing afloat, even though they own its main competitor, such is the danger of a monopoly on large commercial aircraft.

alexpc2012• 3 years ago

Something strange, isn't it? First, the fuselage panel detaches in the only row of seats with no passengers. What is the probability of this happening? Then, an iPhone is sucked into the hole and is found on the edge of a road after falling 5000 meters in perfect condition with an airline message on its screen. Really weird.

Zetobal• 3 years ago

That's what happens if your employees don't care about your company.

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

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