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Door blows off Boeing 777X during stress test

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Re: Door blows off Boeing 777X during stress test

#41

Post by jussij »

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…

> The entire point of these tests is specifically to break things

When you do these types of tests you are testing for a expected outcome.

If you do a test and the outcome is un-expected (i.e. the fuselage fails prematurely) it means your engineering and the expectations built around that engineering are wrong.

Re: Door blows off Boeing 777X during stress test

#42

Post by txcwpalpha »

jussij wrote: post #41
txcwpalpha wrote: post #29

Earlier quoted context omitted.

>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…

> The entire point of these tests is specifically to break things When you do these types of tests you are testing for a expected outcome. If you do a test and the outcome is un-expected (i.e. the fuselage fails prematurely) it means your engineering and the expectations built around that engineering are wrong.

This is incorrect. These tests are specifically done because they want to gather data on what the failure loads (which are previously unknown) are.

Re: Door blows off Boeing 777X during stress test

#43

Post by jussij »

txcwpalpha wrote: post #40
jussij wrote: post #36

Earlier quoted context omitted.

The first time the A380 tried the test it failed. Read the link. And yes it did eventually pass that wing test only because if it had not it would not never have been certified.

>The first time the A380 tried the test it failed. Read the link. I suggest you read it. The A380 did not fail. It says so in the link you provided.

"We'll be able to demonstrate" that the plane meets requirements, "maybe with some refinements needed for certification in time for first delivery at the end of the year," Kracht said in a telephone interview Thursday.

We'll is we will (i.e some time in the future).

Re: Door blows off Boeing 777X during stress test

#45

Post by 29_29 »

jussij wrote: post #26
cyberferret wrote: post #16

It's a stress test. You would expect things to break during a stress test. > "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." Here is another video of a 777 wing test where it broke at 154% of the [s/normal/maximum theoretical/] load - a bit beyond what was expected by the engineering team. https://www.youtube.com/watch?v=Ai2H…

> 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...

I'd rather it break in a stress test - than when I'm on it.

Re: Door blows off Boeing 777X during stress test

#46

Post by txcwpalpha »

jussij wrote: post #43
txcwpalpha wrote: post #40

Earlier quoted context omitted.

>The first time the A380 tried the test it failed. Read the link. I suggest you read it. The A380 did not fail. It says so in the link you provided.

"We'll be able to demonstrate" that the plane meets requirements, "maybe with some refinements needed for certification in time for first delivery at the end of the year," Kracht said in a telephone interview Thursday. We'll is we will (i.e some time in the future).

The A380 was already in production at the time of the Feb 2006 test. No modifications to the wings were required because it did not fail it's structural stress test. The entire point of the test was to gather data on what load the test wings (which are weaker than the production wings) failed at, which is why they intentionally broke the wings. The engineers then used this data to calculate the load limit that the production wings (which are stronger than the test wings) failed at. The calculated load limit for the production wings was above the EASA certification requirement, meaning the wings passed their test.

Re: Door blows off Boeing 777X during stress test

#48

Post by anigbrowl »

cyberferret wrote: post #16

It's a stress test. You would expect things to break during a stress test. > "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." Here is another video of a 777 wing test where it broke at 154% of the [s/normal/maximum theoretical/] load - a bit beyond what was expected by the engineering team. https://www.youtube.com/watch?v=Ai2H…

That's...not something any client wants to hear.

Re: Door blows off Boeing 777X during stress test

#49

Post by RcouF1uZ4gsC »

cyberferret wrote: post #16

It's a stress test. You would expect things to break during a stress test. > "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." Here is another video of a 777 wing test where it broke at 154% of the [s/normal/maximum theoretical/] load - a bit beyond what was expected by the engineering team. https://www.youtube.com/watch?v=Ai2H…

Good point about it being normal for stuff to break during a stress test. However, it seems the door blowing off is not something that normally happens and that to me is more worrisome than if it was a common failure when the stresses greatly exceed the theoretical limits.

>Former Boeing Engineer Dr. Todd Curtis runs Airsafe.com and said this doesn't happen often. "I've never heard of a case where a door popped off like this during a stress test before," he said. "Doesn't mean it hasn't happened before, I'm just not aware of it."

Re: Door blows off Boeing 777X during stress test

#50

Post by jussij »

txcwpalpha wrote: post #46
jussij wrote: post #43

Earlier quoted context omitted.

"We'll be able to demonstrate" that the plane meets requirements, "maybe with some refinements needed for certification in time for first delivery at the end of the year," Kracht said in a telephone interview Thursday. We'll is we will (i.e some time in the future).

The A380 was already in production at the time of the Feb 2006 test. No modifications to the wings were required because it did not fail it's structural stress test. The entire point of the test was to gather data on what load the test wings (which are weaker than the production wings) failed at, which is why they intentionally broke the wings. The engineers then used this data to calculate the load limit that the pr…

> The A380 was already in production at the time of the Feb 2006 test.

There is more than one version of the A380.

But there was no A380 Airbus with a 550 seat capacity in service at that time.

The whole point of that wing testing was so this newer, higher capacity A380 could get certification.

http://www.modernairliners.com/airbus-a380/airbus-a380_histo...

25 October 2007 - The first commercial flight of the A380 took place from Singapore to Sydney. All seats were auctioned off for charity.

FYI that link also shows the certification wing test failed:

14 February 2006 - Stress testing of the wing revealed that the wing broke at 146% of the required level instead of 150%. Further strengthening was added which increased the weight by 30Kg

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