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Boeing knew of flaw in part linked to UPS plane crash, NTSB report says
- toomuchtodo 9mo agohttps://www.ntsb.gov/investigations/Documents/DCA26MA024%20Investigative%20Update.pdf https://www.ntsb.gov/investigations/Documents/DCA26MA024%20I...
- yearolinuxdsktp 9mo agoThank you this document is so much more straightforward than most YouTube videos covering the same.
- SilverElfin 9mo agoEvery 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 9mo agoSounds 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#ABC_check_system 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 9mo agoThanks 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 9mo agoI’m guessing that manufacturers know of lots of flaws in the parts they make.
- autoexec 9mo agoHopefully they don't usually downplay the risks of dangerous known flaws in critical parts like Boeing seems to have done in this case.
- hsbauauvhabzb 9mo agoThey 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.
- rootusrootus 9mo agoIs that your professional assessment as an aerospace engineer, or as a software engineer?
- autoexec 9mo agoIt's my assessment of the professional assessments of experts such as aviation safety consultant and former air accident investigator Tim Atkinson and former FAA and NTSB investigator Jeff Guzzetti, as well as the contents of the NTSB's report, and Boeing's well documented history of putting profit over safety. I believe that it's the opinion of experts that Boeing either misjudged the safety risk of the bearing assembly when they should not have or that they incorrectly downplayed that risk when disclosing the flaw to their customers and I'm inclined to believe those experts because Boeing has already demonstrated themselves to be outright dishonest and negligent when it comes to the safety of their products. That said, while I would not be surprised if things truly are as they currently appear to be, my assessment is always subject to change if additional information comes to light which makes that less likely to be the case.
- potato3732842 9mo ago
- jacquesm 9mo agoI 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.
- mrtksn 9mo 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 9mo agoAs 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.
- mrtksn 9mo agoI'm sure that a flaw in the plane can be handled more gracefully by the more skilled set of pilots however that's not the point really. Their point was that the flaw in the plane wasn't a big deal and the loss of life and equipment wasn't Boeing's fault, which wasn't true.
- benced 9mo agoThe reason we focus on the OEM more than the pilots is that Boeing getting its act together (or being regulated to do so) is more scalable than every pilot in the world becoming more skilled. Individually blaming pilots isn't effective, regardless of whether you're morally for or against it.
- DoesntMatter22 9mo agoIsn't it a mostly Boeing project that is going to go around the moon next month? I'm really afraid for that crew.
- CGMthrowaway 9mo agoThe headline is missing an important bit. Boeing knew of the flaw, and sent a letter to airlines about it. In 2011.
- rabidonrails 9mo agoWell 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 9mo agoYeah 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.
- itopaloglu83 9mo agoAnd that’s how McDonnell Douglas took over Boeing from the inside and eroded its engineering mindset altogether.
- dralley 9mo agoThe FAA has not determined that this flaw did lead to a safety of flight condition. Investigation is still ongoing.
- autoexec 9mo agoA 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
- vsgherzi 9mo agoInsane 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
- mmooss 9mo agoI 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 9mo ago12/32 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.
- dylan604 9mo agothe 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
- mmooss 9mo agoRight, it was risk management. I doubt that leaking fuel would be acceptable risk management for a commercial passenger plane at a public airport. Obviously they could have designed something that could expand and contract if they thought it was worth it.
- mmooss 9mo agoSome 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.
- ksaj 9mo agoThey do mention that the DC10 (this plane's predecessor) was decommissioned for similar issues.
- fransje26 9mo agoThis article does not? And the DC-10 was not decommissioned. It is, in fact, still in service.
- beowulfey 9mo agoThey may have meant grounded, not decommissioned. DC-10s were grounded alongside the MD-11s. https://www.flightglobal.com/safety/us-faa-broadens-md-11-grounding-order-to-remaining-dc-10-fleets/165313.article https://www.flightglobal.com/safety/us-faa-broadens-md-11-gr...
- ksaj 9mo agoClose. I meant decommissioned from the UPS fleet, nearly 25 years ago. MD11 was considered a more modern and flexible replacement.
- kayfox 9mo agoDid UPS Airlines ever fly the DC-10/MD10? FedEx did and they retired them in the last 5 years because they had reached the end of their economical service lifetime and not because of any major flaw.
- lashingflank 9mo agoOne 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 9mo agoAlternative to paywall: https://archive.ph/8xF1w https://archive.ph/8xF1w
- rob74 9mo agoI 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 9mo ago"There are two wings right?"
- potato3732842 9mo 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 9mo agoWhenever I see these I think of Fight Club
- 12_throw_away 9mo agoReading 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%20Investigative%20Update.pdf https://www.ntsb.gov/investigations/Documents/DCA26MA024%20I...
- tiahura 9mo agoTo be fair, there were a few folks on x avh and the other typical sites who guessed the cause pretty quickly.
- thomascountz 9mo agoI 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 https://www.ntsb.gov/investigations/Pages/DCA24MA063.aspx
- metalman 9mo ago
- burnt-resistor 9mo agoThis 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.