Boeing knew of flaw in part linked to UPS plane crash, NTSB report says

https://www.bbc.com/news/articles/cly56w0p9e1o

by 1659447091 • 6 months ago

343 162 6 months ago

bbc.com

toomuchtodo• 6 months ago

https://www.ntsb.gov/investigations/Documents/DCA26MA024%20I...

yearolinuxdsktp• 6 months ago

Thank you this document is so much more straightforward than most YouTube videos covering the same.

SilverElfin• 6 months ago

Every five years feels too infrequent. These are planes that are 30 years old and have done 100,000 hours of flying. Apparently UPS policy is to keep them around for about 35 years to maximize the ROI. But maybe once they hit a particular age they need to be inspected deeply every few months.

I am not an expert, however. Can metal fatigue be detected with such infrequent inspection?

nebula8804• 6 months ago

Sounds like it is included as part of standardized airplane checks based on age of aircraft + hours flown.

[1] https://en.wikipedia.org/wiki/Aircraft_maintenance_checks#AB...

On things like D check, the aircraft is essentially completely taken apart and inspected at that level typically taking 50,000 man hours and 6 month-1 year of time.

lostlogin• 6 months ago

Thanks for this post. I’m blown away by that 50,000 hours figure.

The article mentions the cost and that Boeing underestimates it. When you divide the cost by the number of hours, it seems very reasonable. Parts and materials being included. I’m surprised any job that extensive isn’t even more expensive.

genghisjahn• 6 months ago

I’m guessing that manufacturers know of lots of flaws in the parts they make.

autoexec5• 6 months ago

Hopefully they don't usually downplay the risks of dangerous known flaws in critical parts like Boeing seems to have done in this case.

hsbauauvhabzb• 6 months ago

They learn pretty quickly to downplay things when their whistleblower collegese either fall down the stairs or kill themselves after telling loved ones that if they die it was not by their own hands.

rootusrootus2• 6 months ago

Is that your professional assessment as an aerospace engineer, or as a software engineer?

potato37328422• 6 months ago

You can't in good conscience advertise a complex assembly as fit for some purpose without knowing how close the component widgets are to their various modes of failure.

jacquesm15• 6 months ago

I recall a lot of fingerpointing minutes after the crash by people blaming the presumably foreign maintenance crew.

Even now there is a lot of uncertainty around this crash, maintenance - or lack thereof - or even wrong maintenance could still be a factor. But given the location of the part asking for a 'visual inspection' is a pretty strange move, the part is all but inaccessible when it is in its normal position and even with an endoscope it would be pretty hard to determine whether or not the part had weakened. That's just not going to show up visually until it is way too late unless the part has been especially prepared to announce the presence of hairline cracks.

You'd have to disassemble a good chunk of the wing to gain access to the part based on the pictures I've seen of how it all holds together when assembled.

mrtksn3• 6 months ago

blaming the presumably foreign maintenance crew

The same happened with MCAS, the pro-Boeing argument was that if those were American pilots it would have been fine.

nickff• 6 months ago

As a matter of fact, the same issue did occur to US-based-airlines, and the pilots did catch it. That does not however answer the question of whether they just got lucky, or were more skilled, though there are some indications that it may have been skill.

Dylan168073• 6 months ago

It's not really the same. Pilots need extensive training for how to handle emergency situations and maintenance crew don't. It's not super harsh to say that pilots in different regions are at different levels for those weird situations. It is super harsh to say that maintenance crews in some regions can't do their baseline job.

sofixa• 6 months ago

Boeing themselves, including their CEOs, kept repeating that bullshit. Even after the FAA finally realised the issue, and refused Boeing's first attempted fix that relied on pilots being able to identify the situation and enact the procedure within 10 seconds (in various tests in a Southwest training center, it was around 30s on average). Then the FAA mandated a full redesign of the MCAS system to actually rely on two sensors and handle disagreements. And Calhoun kept repeating that "this wouldn't have happened with American pilots".

DoesntMatter22• 6 months ago

Isn't it a mostly Boeing project that is going to go around the moon next month? I'm really afraid for that crew.

dylan6043• 6 months ago

Why would you be afraid for them when the Orion capsule worked so flawlessly...oh right.

mrpippy• 6 months ago

Are you talking about Starliner? Starliner's 2 flights have been problematic to say the least, but Orion's single (uncrewed) flight went pretty well.

CGMthrowaway• 6 months ago

The headline is missing an important bit.

Boeing knew of the flaw, and sent a letter to airlines about it. In 2011.

rabidonrails• 6 months ago

Well yes but Boeing also said it "would not result in a safety of flight condition."

There's a lot of gray going on here.

hahahahhaah• 6 months ago

Yeah saved boeing losing face and sales by requiring all the planes be grounded and fixed. Just eye it up every 5 years, if you want to.

dralley• 6 months ago

The FAA has not determined that this flaw did lead to a safety of flight condition. Investigation is still ongoing.

autoexec5• 6 months ago

A former air accident investigator who works as an aviation safety consultant said "It's extraordinary that Boeing concluded that a failure of this part would not have safety consequences," and said the report was "disturbing"

Doesn't seem like gray to me. It seems a company who has a history of cutting corners and ignoring or downplaying safety problems did exactly that in this case too which resulted in the deaths of many people. UPS made an error here as well in trusting Boeing when they said it wasn't a safety issue and they should have installed the revised bearing assembly out of an abundance of caution, but I don't know much they would have known back in 2011 about the changes at Boeing that prioritized profit over safety following the merger with McDonnell Douglas

bombcar• 6 months ago

Apparently they expected it to blow up on the ground, so technically the plane wasn't flying yet ...

somat• 6 months ago

I am wondering what the exact fail mode here is.

Because my naive conclusion after looking at the part in question is exactly the same "would not result in a safety of flight condition." if the bearing cracked at the point in question it is going nowhere, the bearing is still captive in its housing. hell it looks like it could have been designed as two pieces and it would work the same. the large bolt is what is holding the engine on.

The best I can come up with is that a split bearing causes increased wear on the mounting bracket and nobody noticed for a long time.

Anyhow, here is the ntsb update in question https://www.ntsb.gov/investigations/Documents/DCA26MA024%20I...

otikik• 6 months ago

What's gray? To me it looks like written proof of incompetence.

jjk1662• 6 months ago

Which may have been a very reasonable conclusion based on what they knew of the issue. The letter sent out reported a split of the bearing race. A split bearing race won't prevent it from supporting the load. It's easily possible that Boeing's simulation of an aircraft operating with a split bearing race was fine.

The NTSB investigation found that for this crash, not only did the bearing race crack, but also that the bearing lugs, which hold the bearing in place, were fractured. I don't have access to the original text of the letter Boeing sent out, but based on the NTSB report, it sounds like only the issue with the bearing race was previously identified. The two may very well be related, but that doesn't mean that the lug fractures are an expected result of the race failure - perhaps some contributing factor made the lugs more susceptible than predicted. It also remains possible that the bearing damage is a red herring; the aircraft was nearing the end of its service life and had known structural issues in other parts of the pylon. The fact is that for more than a decade after the bearing race issue was reported, it didn't result in a safety of flight condition.

The insinuation that Boeing was deliberately trying to hide or downplay a known issue is simply unwarranted. It would be irresponsible for the NSTB not to mention a known issue that could have potentially been relevant, it's not evidence the issue was improperly handled.

WillPostForFood• 6 months ago

FWIW, the MD-11 was designed by McDonnell Douglas, and manufactured by McDonnell Douglas in 1991, before the Boeing merger. A McDonnell Douglas DC-10 failed in a similar way in Chicago in 1979, so it the issue may go way back.

topspin• 6 months ago

AA Flight 191 in 1979, 273 dead. American Airlines invented their own engine removal procedure using a forklift and damaged a pylon and mounting bracket. The engine ripped off the wing on takeoff.

philipwhiuk• 6 months ago

This would be a better defense if not for the aphorism that "McDonnell-Douglas bought Boeing with Boeing's money"

sidewndr46• 6 months ago

I'm reasonably certain it was McDonnel Douglas that acquired Boeing with Boeing's own money. Most likely everyone who designed that plane has retired at this point anyways.

rootusrootus2• 6 months ago

That is the critical bit. They knew about it, and we can speculate that their assessment was wrong, but there is no coverup, no scandal. Sometimes engineers are wrong.

vsgherzi3• 6 months ago

Insane that we can have places like the skunk works create the sr71 and operate on shoe string budgets but the largest passenger plane company in the world can’t accurately assess risk on planes far under the former planes Mach 3 record

mmooss8• 6 months ago

I don't see that as a valid comparison. SR-71s could operate with a much higher level of risk than commercial passenger planes. IIRC, SR-71s leaked fuel on the ground, and their wings dragged on the ground without special attachments. Pilots needed special pressure suits, etc.

I also expect that they were much less complex than an aircraft that provides a comfortable, pressurized cabin; the high level of safety mentioned above; freight capacity; etc.

Also, despite Boeing's recent problems, I would guess that commerical passenger planes are far more safe than they were decades ago when the SR-71 was developed. Accidents were much more common despite many fewer flights, iirc.

imadethis• 6 months ago

12/32 SR71s were lost in the 33 years they were flying. 11/200 MD-11s have been hull-lost from 1988-2025. Not to mention that passenger/cargo planes will put on a lot more flight hours than the SR71s did in a given year.

dylan6043• 6 months ago

the SR-71 leaking fuel on the ground was not a design flaw. it was designed to be operated at speed where things would expand to fill in. if they were filled in on the ground, they'd have no place to expand at speed/temps. the risk assessment was that it was better to leak fuel on the ground rather than blowing up at speed/temp

jacquesm15• 6 months ago

The SR-71 is pressurized. Not to sea level pressure, obviously, but it wasn't exactly unpressurized either. The main reason the crew wore pressure suits is for heat retention and oxygen delivery.

The_President• 6 months ago

The U-2 is the plane that drags the wings on dolly wheels.

vsgherzi3• 6 months ago

Much less complex? I'm not sure about that for a plane that's expected to travel so fast. In terms of features I'm sure modern passenger planes have quite a bit more. I'm sure planes are absolutely safer now, the point I'm trying to make is the SR71 was thought to be almost impossible to make yet they were able to do it with an impressively small team and (rumored) budget. Yet so many years later we struggle to make reliable workhorse planes that have no such expectations of going faster than anything before. I don't think it's a stretch to say that we could and should be making much better planes.

dghlsakjg2• 6 months ago

Look up the hull loss numbers on the SR-71. More than a third of them were lost in incidents despite never making contact with the enemy.

It was also insanely expensive to operate: $300k/hour in 1990 dollars, and there aren’t reliable numbers on development costs with all of the black budgets.

tempest_• 6 months ago

33 percent attrition and could only fly once a week.

I know satellites and drones have replaced the sr71 but it would be cool if someone would build a plane as capable again.

vsgherzi3• 6 months ago

the point I was trying to make is that the creation of the sr71 was a physics defying problem and something considered nigh impossible. A passenger plane has much less complex expectations. Now don't take this to meant none at all, of course they have to operate 24/ 7 and have high reliability and safety. However, in a world where we can build the SR71 I don't see what we can't build the latter. We can and should be building better planes. I think that's pretty evident with this issue and the infamous software issue of the other boeing planes.

mmooss8• 6 months ago

Some are forgetting how risk in technology works: No technology is designed or operated without flaws; that's an absurd approach and impossible to implement.

To reduce negative outcomes, we use risk management: assessing the likely lifetime cost of the flaw, and taking cost-effective measures to reduce the risk to an acceptable level. As a familiar example, redundant mass storage drives are much more cost-effective than high-reliability mass storage drives.

ksaj2• 6 months ago

They do mention that the DC10 (this plane's predecessor) was decommissioned for similar issues.

fransje264• 6 months ago

This article does not?

And the DC-10 was not decommissioned. It is, in fact, still in service.

itopaloglu832• 6 months ago

The DC-10 and MD-11 are both McDonnell Douglas. They merged into Boeing, but instead of Boeing’s safety and innovation oriented culture, McDonnell‘s finance bros won with their cost and corner cutting measures.

Aviation rules are written by blood, you either follow them or you add a few more lines with your own blood.

anal_reactor2• 6 months ago

Sure, but the problem is, Boeing is a company that has a proven record of lying about the flaws of their products. There's a huge difference between "shit, nobody thought this part would crack in this way" and "we knew someone would eventually die, but we realized that paying the damages in case this happens is cheaper than preventing the disaster in the first place".

mmooss8• 6 months ago

"we knew someone would eventually die, but we realized that paying the damages in case this happens is cheaper than preventing the disaster in the first place".

The fundamental reality is, we can always spend more to prevent another death; and we must draw the line somewhere.

People don't like it, but your latter example is the risk management I'm talking about, and it's unavoidable. Nobody can make airplanes that have no risk of killing people - the only answer would be no airplanes at all (which would result in more automobile deaths, more deaths because life-saving resources are unavailable, etc.). The calculation of cost per death prevented is a real one, and is done by manufacturers of planes, cars, etc.

The problem with your wording is the criteria of paying damages, rather than the industry-standard value for human life. Again, that is awful to think about but there's no way around it.

Edit: And I'm not saying, at all, that Boeing made the right decision here. I don't know enough to say, and Boeing's safety reputation is poor.

IAmBroom• 6 months ago

Please point to someone ITT who is forgetting that. I can't see any such posts.

And "shit happens; suck it up, buttercup" is not an approved PHA determination.

lashingflank• 6 months ago

One thing that worries me about the current political climate is that everything can be politicized. Do we know that behind the scenes Boeing wasn't paying a bribe for better treatment in the report? Or do we know that this report is especially damning because they refused to bribe? I guess we never knew for sure but the level of corruption now is so high I just have no faith that there hasn't been meddling in these investigations. It's the pernicious effect of corruption in a society and I don't think we're ready for it.

stevenjgarner• 6 months ago

Alternative to paywall: https://archive.ph/8xF1w

rob74• 6 months ago

I wonder on what basis Boeing thought that damage to a load-bearing part could be safely ignored? I hope it wasn't "nothing bad has happened for 50+ years, so it's unlikely to happen now"?

blitzar• 6 months ago

"There are two wings right?"

potato37328422• 6 months ago

I wonder on what basis Boeing thought that damage to a load-bearing part could be safely ignored?

Usually this is because the design constraints are complex and in satisfying one you wind up having orders of magnitude more overkill than you need on others.

For example, in situations involving hollow shafts with through shafts or perhaps fluid passages often times you wind up with insanely huge for the load bearing supporting the outer most part because it simply needs to be that big in order to fit around the shaft and have space for reasonable sized roller elements for the speed and realistic race thicknesses, etc. Sure you could go custom, but $$, sure you could use needles or balls, but maybe the stuff on either side has reasons it shouldn't be hard like a race and that might add assembly/construction cost. Now say this overkill bearing is held up by a big web in a big honkin cast housing, because the housing needs to be like that for structural reasons (say it's a specialty pump or maybe this housing is load bearing in the overall assembly, like a tractor's gearbox). Now, say this bearing is in some more complex gearbox that has lubrication windage problems. A valid fix might be to go and cut out a chunk of the web that holds this bearing. Sure it's only supported by 300deg now instead of 360, but it was so overkill to begin with that doesn't matter.

Edit: better example: You can roach dozens of automotive cartridge style wheel bearings without hurting the knuckle it presses into because the knuckle has to be so strong to withstand suspension forces you basically can't apply enough force via the wheel failure to break it and the assembly becomes unserviceable faster than you can get to the point of damaging it by wearing through it.

Edit2: You also need to consider the cost of QA and testing. Sometimes it's cheaper to do a simple overkill waste of material design than something than to do speed holes and engineered webs, etc, etc, because all those features add testing cost as well as manufacturing cost and (especially in ye olden days of the slide rule) make it harder to predict stuff like resonance, exact failure mode, etc, etc and every feature has to be QA'd to some extent. And this all needs to be balanced against expected production volume.

androiddrew• 6 months ago

Whenever I see these I think of Fight Club

12_throw_away• 6 months ago

Reading the actual NTSB report [1], my first reaction is just my usual awe at the professionalism of the NTSB. They started with a 3000-ft-long debris field and in the end could say "here are the microscopic stress fractures in the left pylon aft mount bulkhead's wing clevis spherical bearing assembly's ball element's forward bearing race".

[1] https://www.ntsb.gov/investigations/Documents/DCA26MA024%20I...

tiahura• 6 months ago

To be fair, there were a few folks on x avh and the other typical sites who guessed the cause pretty quickly.

dandelany• 6 months ago

Like most things, guessing and proving require vastly different efforts. In aviation, a few more orders of magnitude than most.

jacquesm15• 6 months ago

If a few thousand people speculate some of them will get it right. It means nothing.

thomascountz• 6 months ago

I share your awe of the NTSB and their reports. Here's my favorite quote from the Alaskan Airlines door plug incident[1]:

   We determined that the probable cause of this accident was the in-flight separation of the left MED plug due to Boeing’s failure to provide adequate training, guidance, and oversight necessary to ensure that manufacturing personnel could consistently and correctly comply with its parts removal process, which was intended to document and ensure that the securing bolts and hardware that were removed to facilitate rework during the manufacturing process were properly reinstalled.

[1]: https://www.ntsb.gov/investigations/Pages/DCA24MA063.aspx

metalman• 6 months ago

as a pilot, we attend regular training sessions, often hosting senior accident investigators who continue to follow a strict logical method where you start with nothing, zero knowledge, just physical evidence and recordings, eyes, ears, nose, touch, and I bet the sneaky ones are tasting stuff. It's a small community, everyone has lost a friend, knowledge and information is sought and shared in a very particular way when it comes to saftey and reliability, though of course there are cheats and greed, passive agresives comiting crimes of omission. and so, here we are, again.

burnt-resistor• 6 months ago

This is the problem with regulatory capture (corruption), "self-regulation", and billionaire bootlicking bozos who shoot their mouths off about "red tape" and "big gubberment".

The part was redesigned without the groove but wasn't mandated because Boeing said even the old part could be used, which is insane. Clearly, the new part wasn't installed and likely 1-2 inspections failed to notice it was broken.

Boeing knew of flaw in part linked to UPS plane crash, NTSB report says

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