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

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31–40 of 188 posts

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

#31

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

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.

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.

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

#32
post #21

Earlier quoted context omitted.

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.

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 hold…

Juan Browne (blancolirio) breaks this down:

https://www.youtube.com/watch?v=q5OQzpilyag

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

#33
post #5

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 an…

> 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.

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

#34

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

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

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.

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

#35
post #18

Earlier quoted context omitted.

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 menti…

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

Right, 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.

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

#36
post #33
post #5

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 an…

> 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.

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.

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

#37
post #36
post #33

Earlier quoted context omitted.

> 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.

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.

I'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.

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

#38
post #35

Earlier quoted context omitted.

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

Right, 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.

They designed special fuel that wouldn’t catch on fire under normal circumstances.

Also, this was done because airframe skin temps exceeded 400F during flight due to the high speeds.

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

#39
post #37
post #36

Earlier quoted context omitted.

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.

I'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.

The 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.

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

#40
post #23

Earlier quoted context omitted.

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.

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.

Interestingly, the reason American Airlines was removing the engines (and pylons) in the first place was to replace that same aft bearing. McDonnell-Douglas had found that the aft bearing could wear out sooner than expected and issued a service bulletin requiring replacement. There is mention of it in the AA191 NTSB report[1] and also at Admiral Cloudberg's article on the accident[2].

[1] https://www.ntsb.gov/investigations/AccidentReports/Reports/... [2] https://admiralcloudberg.medium.com/rain-of-fire-falling-the...

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