Whenever I see these I think of Fight Club
Boeing knew of flaw in part linked to UPS plane crash, NTSB report says
121–130 of 188 posts
Re: Boeing knew of flaw in part linked to UPS plane crash, NTSB report says
#122Earlier quoted context omitted.
After watching the below video, it's the excess bearing play and thus no-longer-constrained force directions that would seem to be the issue. With a proper tolerance bearing in place, the force is constrained so that other parts are only stressed in directions they're well suited to handle (because the bearing takes the load). Once the bearing develops excess tolerance, you've got a bucking engine that (to your point…
> The fact that Boeing supposedly modeled this and came up with non-safety critical in the event of bearing breakage... curious how that will turn out. They'd have to show at least one plane with a bearing gone that still flies as intended. I suggest we break one on purpose, put the full complement of Boeing execs on that plane to prove its safety given the alternative of retracting that statement.
My company has a policy limiting the number of high level execs traveling on a plane at a time. I wonder if plane manufacturers have similar restrictions. It’d be an ironic to for them to simultaneously assert that their planes are safe for the general public, and also believe the risk is too high for a planeload of their execs to fly in one.
Re: Boeing knew of flaw in part linked to UPS plane crash, NTSB report says
#123Earlier quoted context omitted.
> The fact that Boeing supposedly modeled this and came up with non-safety critical in the event of bearing breakage... curious how that will turn out. They'd have to show at least one plane with a bearing gone that still flies as intended. I suggest we break one on purpose, put the full complement of Boeing execs on that plane to prove its safety given the alternative of retracting that statement.
My company has a policy limiting the number of high level execs traveling on a plane at a time. I wonder if plane manufacturers have similar restrictions. It’d be an ironic to for them to simultaneously assert that their planes are safe for the general public, and also believe the risk is too high for a planeload of their execs to fly in one.
Controlled flight into terrain is a thing
Re: Boeing knew of flaw in part linked to UPS plane crash, NTSB report says
#124Earlier quoted context omitted.
That's indeed a very naive conclusion. Once that bearing is gone the stress that it would normally allow to escape on account of rotation would be directly transferred to the metal around it and to the bolts holding the whole thing in place. Guess what broke first? So if that bearing went that's not quite a smoking gun yet but it would definitely be a step closer to a root cause.
After watching the below video, it's the excess bearing play and thus no-longer-constrained force directions that would seem to be the issue. With a proper tolerance bearing in place, the force is constrained so that other parts are only stressed in directions they're well suited to handle (because the bearing takes the load). Once the bearing develops excess tolerance, you've got a bucking engine that (to your point…
To see extreme examples of this, look at any wallowed-out/wallered-out through-bore in construction equipment (e.g. excavator buckets), particularly when a pin hasn't been greased, or is seized.
This same scenario combined with the amount of vibration and stresses caused by the engine, should scream "this is a catastrophe waiting to happen" for any engineer.
Re: Boeing knew of flaw in part linked to UPS plane crash, NTSB report says
#125Earlier quoted context omitted.
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…
I think every company operating Boeing aircraft should have reviewed their stance on Boeing directives in light of MCAS and the aftermath by now. If they did not that is a failure of sorts as well.
> I think every company operating Boeing aircraft should have reviewed their stance on Boeing directives in light of MCAS and the aftermath by now. If they did not that is a failure of sorts as well.
Actual question: would an airline have the engineering competence to second-guess an airplane manufacturer's engineering guidance? They operate airplanes but don't build them, and I'd assume they'd out of necessity need to trust the manufacturer's judgement.
Re: Boeing knew of flaw in part linked to UPS plane crash, NTSB report says
#126Earlier quoted context omitted.
I think every company operating Boeing aircraft should have reviewed their stance on Boeing directives in light of MCAS and the aftermath by now. If they did not that is a failure of sorts as well.
> I think every company operating Boeing aircraft should have reviewed their stance on Boeing directives in light of MCAS and the aftermath by now. If they did not that is a failure of sorts as well. Actual question: would an airline have the engineering competence to second-guess an airplane manufacturer's engineering guidance? They operate airplanes but don't build them, and I'd assume they'd out of necessity need…
Maybe the airline doesn’t but their insurance company should, if not directly than indirectly.
Re: Boeing knew of flaw in part linked to UPS plane crash, NTSB report says
#127Earlier quoted context omitted.
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.
It was replaced because the USSR managed to shoot one down. Spy satellites are as of yet off limits.
I think you might be misremembering the shoot-down of a U2 plane, which was also a U.S. spy plane operating around the same time.
Re: Boeing knew of flaw in part linked to UPS plane crash, NTSB report says
#128The headline is missing an important bit. Boeing knew of the flaw, and sent a letter to airlines about it. In 2011.
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.
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.
Re: Boeing knew of flaw in part linked to UPS plane crash, NTSB report says
#129The headline is missing an important bit. Boeing knew of the flaw, and sent a letter to airlines about it. In 2011.
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.
Re: Boeing knew of flaw in part linked to UPS plane crash, NTSB report says
#130I’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.
Is that your professional assessment as an aerospace engineer, or as a software engineer?