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Door blows off Boeing 777X during stress test

komonews.com

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Re: Door blows off Boeing 777X during stress test

#81

Post by inferiorhuman »

Groxx wrote: post #59
tpmx wrote: post #20

Earlier quoted context omitted.

"A door blew off a Boeing 777X as the new plane was undergoing what was supposed to be its final structural inspection by federal regulators." It's literally the first sentence of the article. I doubt Boeing were pushing the envelopes further than the FAA required. And a door fell out.

The second, third, and fourth sentences seem to imply otherwise? > The test is meant to push the plane beyond its limits. Engineers had the plane pressurized and on the ground. They loaded it up well beyond capacity and bent its wings in an extreme manner, in a way almost certain to never happen in the real world. and also further down, more "not necessarily a normal test" evidence: > ... The ultimate load test is th…

The second, third, and fourth sentences seem to imply otherwise?

Semantics.

https://www.seattletimes.com/business/boeing-aerospace/door-...

The Seattle Times explains it thusly:

During the ultimate load test, the wings are then pulled upward. To pass the test and be certified, the wings must bend without breaking until the load on them reaches at least 150 percent of the normally expected load.

…

Sometimes this final test is continued beyond the 150 percent load target until a wing actually breaks. But not always.

…

This time, however, though the wings did not give way; it was one of the doors that failed — an outcome that is definitely not supposed to happen.

Re: Door blows off Boeing 777X during stress test

#82

Post by inferiorhuman »

txcwpalpha wrote: post #29
jussij wrote: post #26

Earlier quoted context omitted.

> You would expect things to break during a stress test. Except, the whole point of the test is to stress the plane and to have nothing break. The test is designed to make sure the aircraft has built-in safety (i.e. is over engineered). When the A380 was attempting to earn it's certification it failed a similar static wing test: http://www.airmech.co.uk/forums/showthread.php/5340-A380-Win...

>Except, the whole point of the test is to stress the plane and to have nothing break. What? No it's not. The entire point of these tests is specifically to break things. If nothing breaks, they did not perform the test correctly. >When the A380 was attempting to earn it's certification it failed a similar static wing test: No, it didn't. It passed the test handily. The wing broke well beyond the max load limit, whic…

What? No it's not.

Yes, it is. The point is to check that the wings can take 150% of the rated load. The point of an ultimate load test is NOT to break things.

Re: Door blows off Boeing 777X during stress test

#83

Post by xiphias2 »

,,Investors were disappointed recently when Boeing announced delays in delivering its first 777X model into next year.''

,,Safety is the highest priority at Boeing."

I'm not sure if both of these sentences can be true at the same time. At the same time I wouldn't be a Boeing investor after how the MAX plane was designed.

Re: Door blows off Boeing 777X during stress test

#84

Post by ChuckMcM »

kortilla wrote: post #79
ChuckMcM wrote: post #70

Earlier quoted context omitted.

And it is, it is 154% or slightly more than 2.5x the 'design limit load'.

90% of $100 is not $190

Interestingly the 154% number seems to be gone from the article now

The language is tricky, if you interpret it as I did, or 154% "more" than the design limit, then it is the design limit plus 1.54 more design limits. Like saying you salary is $100 and we're paying you 90% beyond your salary. Then you would expect to get $190.

If you interpret it to be 154% "of" the design limit, then I would agree it would be 1.54x the design limit.

Since other publications from Boeing, and Boeing staff at the "Future of Flight" museum in Everett have said that the planes are safer because they can withstand over twice their design limit, I read the 154% number as the amount "over" the limit.

Since folks from Boeing read Hackernews, it would be great for one of them to chime in here with some clarification :-).

Re: Door blows off Boeing 777X during stress test

#85

Post by ehnto »

clebio wrote: post #47

The front fell off. It's perfectly normal. They towed it out of the environment. https://www.youtube.com/watch?v=3m5qxZm_JqM

A wave hit it, ...in the sea? Chance in a million.

I was trying to find the right place to reply with that video. Classic skit humour.

Re: Door blows off Boeing 777X during stress test

#87

Post by DavidSJ »

fastball wrote: post #55
DavidSJ wrote: post #10

Earlier quoted context omitted.

One would presume this is purely a function of the pressure differential between the cabin and environment, which they presumably controlled for.

Doesn't sound like it. "Engineers had the plane pressurized and on the ground. They loaded it up well beyond capacity and bent its wings in an extreme manner..."

I was responding to a question about the difference between being on the ground and in the air, not one about the many other differences between this test and real-world operation.

Re: Door blows off Boeing 777X during stress test

#88

Post by Aloha »

walrus01 wrote: post #4
bombela wrote: post #2

ads. ads everywhere. it's almost impossible to read the article.

KOMO is owned by Sinclair broadcasting now, which you can Google about and draw your own conclusions.

How do you think Sinclair's purported bias coloring this story?

Re: Door blows off Boeing 777X during stress test

#90

Post by dmix »

ChuckMcM wrote: post #84
kortilla wrote: post #79

Earlier quoted context omitted.

90% of $100 is not $190

Interestingly the 154% number seems to be gone from the article now The language is tricky, if you interpret it as I did, or 154% "more" than the design limit, then it is the design limit plus 1.54 more design limits. Like saying you salary is $100 and we're paying you 90% beyond your salary. Then you would expect to get $190. If you interpret it to be 154% "of" the design limit, then I would agree it would be 1.54x…

It’s in the above Boeing video not the article.
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