Door blows off Boeing 777X during stress test • Hacker News Board

Re: Door blows off Boeing 777X during stress test

#21

Post by cyberferret » Sat, Sep 07, 2019, 1:32 AM UTC

kbenson wrote: post #19

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…

> Here is another video of a 777 wing test where it broke at 154% of the normal load I really hope you mean 154% of the max load, and I hope that max load is engineered to be far above what should be seen in actual service. 50% over the normal service load is not what I would consider extreme, and not something I would expect to be acceptable in an aircraft.

Sorry, I mistyped. It is indeed the maximum theoretical load as calculated by the engineering team.

Re: Door blows off Boeing 777X during stress test

#22

Post by usefulcat » Sat, Sep 07, 2019, 1:34 AM UTC

bombela wrote: post #2

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

I use a curated hosts file and I don't see a single ad on that page.

Re: Door blows off Boeing 777X during stress test

#23

Post by BalinKing » Sat, Sep 07, 2019, 1:35 AM UTC

jrockway wrote: post #18

I like how their PR person says "Safety is the highest priority at Boeing." I feel like the reality is that "doing what our customers tell us so we sell more airplanes than Airbus" is their actual highest priority. I wonder how they fix that. I wonder if it's even possible for a publicly-traded corporation to do?

Personally, I think the onus is on the airlines to not buy unsafe airplanes. (Although, you do then get the argument of "why would they be incentivized to do so," which is admittedly a trickier question.)

Re: Door blows off Boeing 777X during stress test

#24

Post by frankharv » Sat, Sep 07, 2019, 1:35 AM UTC

erikig wrote: post #15

..."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."

I almost didn't shit my pants when the door blew off.

I almost didn't didn't make it out of the burning building.

'Almost Certain' to never happen in the real world. Not very scientific to me. Sounds like PR talk.

Re: Door blows off Boeing 777X during stress test

#25

Post by rolph » Sat, Sep 07, 2019, 1:38 AM UTC

ok 1: the wings were bent in an extreme manner.

so you have a cylinder to a close approximation, with a hole in the side of it. Then you have two levers [wings] affixed to said cylinder, then you apply force to the levers, and distort the cylinder thus distorting the hole in the cylinder....

at this point i would invoke a toplogical parlour trick of making a quarter fall through a dime sized hole as an analogy.

https://prop-tricks.wonderhowto.com/how-to/do-large-coin-sma...

my hypothesis is that the entire airframe flexed causing the door frame to distort thus loosing its grip on the door panel, then FOOF! door goes away!

Re: Door blows off Boeing 777X during stress test

#26

Post by jussij » Sat, Sep 07, 2019, 1:39 AM UTC

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...

Re: Door blows off Boeing 777X during stress test

#27

Post by cyberferret » Sat, Sep 07, 2019, 1:39 AM UTC

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…

Also - need to ensure that all testing methodologies were up to scratch. Here is an article about a KC-135 pressure test that ended up making the plane pop like a balloon [0] - all because the pressure gauge used by the tester didn't have a 'stop' peg and he missed the fact that the needle had cycled around.

A door hatch from the aircraft was found 70 yards away.

[0] - https://theaviationgeekclub.com/time-kc-135-stratotanker-air...

Re: Door blows off Boeing 777X during stress test

#28

Post by org3432 » Sat, Sep 07, 2019, 1:41 AM UTC

That's surprising since afaik it's a plug door that presses up against the airframe when under pressure. So sounds like a major failure of the door or the airframe itself.

Re: Door blows off Boeing 777X during stress test

#29

Post by txcwpalpha » Sat, Sep 07, 2019, 1:41 AM UTC

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...

>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, which is what they were testing for.

edit for the sake of being less of an argumentative asshole: I see where you're coming from when you say that it was a 'failure'. However, what I mean to say is that while the wings failed in the test, the failure was intentional, and the data gathered during the test was exactly what was needed to prove that the A380's wings were strong enough for certification, and the A380 was certified based on the results of this test. In my mind, that means the test passed.

Re: Door blows off Boeing 777X during stress test

#30

Post by senectus1 » Sat, Sep 07, 2019, 1:42 AM UTC

amatecha wrote: post #8

huffmsa wrote: post #7

Earlier quoted context omitted.

Pi-hole my dude. Makes local news sites actually readable.

Nice, thanks for the reminder about pi-hole! Been meaning to set it up for so long now! :)

it really is super easy to do. took me an hour while i was watching TV