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morrisond
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 4:35 pm

There is an interesting idea in 777X thread that this may be one of the reasons they scrapped the Robotic riveting machine.
 
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PW100
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 4:39 pm

BlatantEcho wrote:
scbriml wrote:
BlatantEcho wrote:
So there was a failure 3x at what is ever expected in the most extreme real life situation ever.

Why is this stuff news?


How do you get 3X? Ultimate load is 1.5X expected maximum in-service load.


Uhm, read the article?


I guess he bothered (as I do) that you extended . . . maximum of 1.3 G in normal flight . . . from the linked article to your words . . . the most extreme real life situation ever . . .

Which is a totally different thing.
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Polot
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 4:40 pm

Baldr wrote:
Also, is this the first time that wings being tested at ultimate load (1.5 times the limit load) has resulted in the rupture of the fuselage instead of the wings themselves?

This is not the wing load test you are thinking of.
 
robsaw
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 4:41 pm

TTailedTiger wrote:

I didn't know Boeing or any other company had any obligations to answer to the public. As far as I know they only answer to the regulators. And since this test exceeded government requirements, I still fail to see the outrage. If Boeing said they weren't going to worry about it or fix it then we might have cause for concern.


This whole thread from the title onward is a reflection of trash journalism and arm-chair engineers chiming in.

Really glad there is no expectation on me to make public test cases that fail on any of my projects - particularly when there is ALWAYS a follow-on process to rank, and plan the resolution of every issue.
 
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PW100
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 4:46 pm

Francoflier wrote:
An engineer's job is to aim for the certification requirement, no more, no less.

Less means you can't sell the airplane, more means you've made it too heavy... They were pretty close to the target here, so minor tweaks and reinforcements should be all it takes. That still means they need to analyse the failure, design a fix, test it in massive computer simulations and implement it, including in airframes that have already been built...

Impressive boom, however.

What's funny about the pressurization test is that it essentially takes the airframe to around 1 Bar of differential pressure, which equates to pressurizing the cabin to sea level atmospheric pressure in space...


I'd say the engineers job is first to understand the load (distribution) pattern. Testing beyond minimum requirements usually is quite helpful in that.

I'm sure that they did not increase all the loads at the same time to the max, and "played" around a lot with the different load setting combinations.
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 4:53 pm

keesje wrote:
Are we serious ?! Airframe write-off. No wonder it became so quiet & everybody was looking the other way.



Are you serious?!

From your postings you make me believe that you are/were closely involved with airframe acceptance tests. In that case you should know that these kind of tests (ultimate load test) involve writing off the test specimen. Further, it is not unusual to extend successful testing beyond 150% all the way up to destruction. Airframe write-off is factored in as for this type of testing practice.
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Baldr
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 5:00 pm

Polot wrote:
Baldr wrote:
Also, is this the first time that wings being tested at ultimate load (1.5 times the limit load) has resulted in the rupture of the fuselage instead of the wings themselves?

This is not the wing load test you are thinking of.


Which test am I thinking of then?

The test wing of the 777-200 failed at 154% of limit load; the test wing of the C-5A failed at 125% of limit load, while the test wing of the A380 failed at 146% of limit load -- no massive fuselage ruptures occurred.
 
Exeiowa
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 5:24 pm

I am mostly interested in people building planes that I will not be killed or injured on regardless of the sticker on it. Other people should probably worry about that too. We do not have any say in these things except by public pressure on the people who write the rule book, people who would like to make building their aircraft cheeper already try to add their own pressure in a certain direction.

I am also fed up with the complaining about corporations as this excuses the people who make the decisions from being accountable for their actions, if we instead direct our attention at an amorphous entity instead of the people who actually caused these things to happen.
 
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NeBaNi
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 5:40 pm

The thing that's been weighing on my mind is that Boeing is scalloping the inside walls on the 777x to create extra space for wider seats at 10-abreast than the current 777. If we approximate the fuselage as being a cylinder, wouldn't having thicker walls help, in terms of being able to hold pressure well? Does anyone know if or think Boeing pressurized the interior to more than the amount needed to see how the thinner walls would hold up?
 
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scbriml
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 5:50 pm

NeBaNi wrote:
The thing that's been weighing on my mind is that Boeing is scalloping the inside walls on the 777x to create extra space for wider seats at 10-abreast than the current 777. If we approximate the fuselage as being a cylinder, wouldn't having thicker walls help, in terms of being able to hold pressure well? Does anyone know if or think Boeing pressurized the interior to more than the amount needed to see how the thinner walls would hold up?


The scalloped interior walls are not load bearing. They're just the fancy inside bits that cover and hide all the real gubbins behind it. AFAIK, the 77X physical fuselage (before interior fittings are installed) is exactly the same as all other 777s (but a bit longer).
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TC957
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 6:00 pm

Which actual airframe ( line no ) is this please ?
Boeing should have known that pictures and the real extent of the airframe failure would eventually been leaked out so why hush it up from the beginning ?
 
ewt340
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 6:20 pm

I wonder, B777X interior width is 4" roomier than standard B777. They put thinner interior wall and "better insulation" to make it roomier. They also fitted it with B787's features like bigger windows and better pressurization at 6,000ft.

I wonder if combinations of these changes are the reason to this failure.
 
morrisond
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 6:20 pm

scbriml wrote:
NeBaNi wrote:
The thing that's been weighing on my mind is that Boeing is scalloping the inside walls on the 777x to create extra space for wider seats at 10-abreast than the current 777. If we approximate the fuselage as being a cylinder, wouldn't having thicker walls help, in terms of being able to hold pressure well? Does anyone know if or think Boeing pressurized the interior to more than the amount needed to see how the thinner walls would hold up?


The scalloped interior walls are not load bearing. They're just the fancy inside bits that cover and hide all the real gubbins behind it. AFAIK, the 77X physical fuselage (before interior fittings are installed) is exactly the same as all other 777s (but a bit longer).


Actually the Curve of the inside of the Ribs is kind of eliptical on the 777X with the width slightly wider than the height - making the ribs less deep on the sides vs the crown.

Look at my posts 89 and 90 in this thread - the picture has been of course deleted and I can't find it anywhere else - but it did exist.

viewtopic.php?f=3&t=1411905&p=21102825&hilit=Rib#p21102825

You can kind of see it in this picture - scroll to the bottom of the article https://www.aero-mag.com/ge-aviation-ge9x-boeing-777x/
 
Antarius
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 6:22 pm

TC957 wrote:
Which actual airframe ( line no ) is this please ?
Boeing should have known that pictures and the real extent of the airframe failure would eventually been leaked out so why hush it up from the beginning ?


Because until an RCFA is performed, theres no point speculating and causing confusion.

It's like flying; aviate, navigate, communicate. No point doing part 3 until 1 and 2 are done and clear.
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Carlos01
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 7:04 pm

morrisond wrote:
There is an interesting idea in 777X thread that this may be one of the reasons they scrapped the Robotic riveting machine.


What is going to happen to the airframes already built then?

One thing that worries me heavily, is the fact that this hull popped like a balloon at 99%. They tested this once as far as I know. What if they would put the frame through say 5000 cycles of "normal" stress testing, and then give it another go? I doubt it would reach even the 99% before popping.

Given the chance in the upcoming years to fly on a MAX or an X, would I? Probably yes. Would I feel less secure than in a 737-300 or a 777-200? You bet.
 
Bradin
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 7:17 pm

I think we need to stop hurling stones and rocks here. The static test did what it is suppose to do: independently verify the computer simulations and modeling are accurate.

For the most part, the computer models are correct except for that last 1%. Not only does this impact Boeing, but it also impacts Airbus and any other aircraft manufacturer because everyone uses computer assisted design and modeling for planes. The question becomes an engineering question of why the modeling and the static test differ.

Failure is a tool that can be learned from. How Boeing learns and approaches the failure is a different question.
 
MSPNWA
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 7:30 pm

What this actually is is another chink in the armor of the media and specifically Gates and the ST. They are not a credible news organization. They are agenda-driven, and it's a disservice to the public. They were wrong about the initial failure, and now they're wrong again by trying to save face and making a mountain out of a mole hill in this piece.
 
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Polot
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 7:43 pm

Carlos01 wrote:
morrisond wrote:
There is an interesting idea in 777X thread that this may be one of the reasons they scrapped the Robotic riveting machine.


What is going to happen to the airframes already built then?

One thing that worries me heavily, is the fact that this hull popped like a balloon at 99%. They tested this once as far as I know. What if they would put the frame through say 5000 cycles of "normal" stress testing, and then give it another go? I doubt it would reach even the 99% before popping.

Given the chance in the upcoming years to fly on a MAX or an X, would I? Probably yes. Would I feel less secure than in a 737-300 or a 777-200? You bet.

It did not pop like a balloon at 99%. It popped like a balloon at 148-149%. The problem is it isn’t allowed to pop like a balloon until after 150%. 150% is chosen precisely to account for years of “normal” stress occurring in service to the frame. This frame has also been undergoing various stress tests before this one. This wasn’t a fresh frame right off the production line.
Last edited by Polot on Wed Nov 27, 2019 7:50 pm, edited 1 time in total.
 
Checklist787
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 7:44 pm

seahawk wrote:

Notice the difference, in the Airbus case the damage was limited to a specific area of the wing. The pics of the fuselage show many structural components broken.


With a little bit of glue and tape
It should be fine... :scratchchin:
 
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Polot
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 7:49 pm

Checklist787 wrote:
seahawk wrote:
Bigfootz67 wrote:

This is news because everything remotely negative concerning a Boeing aircraft right now is news. This is what happens when a company screws up as bad as they did with the MAX. It will get fixed. This is not the first time something like this has happened. Note, the A380 had a static test wing break between 1.45 and the target 1.5% target. “The failure occurred last Tuesday between 1.45 and 1.5 times the limit load at a point between the inboard and outboard engines,” says Airbus executive vice president engineering Alain Garcia. “This is within 3% of the 1.5 target, which shows the accuracy of the FEM.” He adds that the ultimate load trial is an “extremely severe test during which a wing deflection of 7.4m (24.3ft) was recorded”. This didn't make the mainstream news because Airbus hadn't suffered a monumental failure on the scale that Boeing inflicted on itself. People in the industry understand this.


Notice the difference, in the Airbus case the damage was limited to a specific area of the wing. The pics of the fuselage show many structural components broken.


With a little bit of glue and tape
It should be fine :scratchchin:

Boeing’s looks worse in picture because a fuselage as more structure than a wing, but that doesn’t mean it is actually worse. You have to filter out which structural components broke because of the stress of the test, and which broke during the “destressing” event (aka the explosive decompression after the failure). The former are important, the second less so (although they can clue you into where you need to look and how to fix the problem).
 
Opus99
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 8:00 pm

Honestly, people need to give it a rest. Why is this news. The aircraft broke at 148% stress out of the required 150%. FAA employees themselves have said it doesn’t need a retest that they need computer verification for any reinforcements and it’s ready to go. Same thing happened with the A380 that is flying safely today. Like really I think everyone just looks for the next Boeing headline and tries their best to attach disaster to it. This is the point of testing and sorry at 148% (99% of the maximum) I mean it seems like a strong structure to me. If it snapped at 150% I hope you’d be all okay with it. Boeing has FAILED recently yes, but the 777x program is still carrying on, the engines have been reinstalled, an engine run has occurred with the new engines and taxi tests are kicking off any moment now. So obviously this clearly wasn’t cause to up root the program and go back to the drawing board. Give it a rest.
 
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 8:17 pm

What Boeing Said:

https://boeing.mediaroom.com/news-relea ... tem=130500

Boeing Statement on 777X Load Testing

"CHICAGO, September 10, 2019 – During final load testing of the 777X static test airplane, a test which involves bending the wings of the airplane up to a level far beyond anything expected in commercial service, an issue arose that required the team to suspend testing. The testing issue occurred during the final minutes of the test, at approximately 99 percent of the final test loads, and involved a depressurization of the aft fuselage.

The test team followed all safety protocols, and we are conducting a comprehensive root-cause assessment over the coming weeks. The static airplane has been successfully undergoing testing since June, and this was the final test for the static test article. While our root cause assessment continues, at this time we do not expect that this will have a significant impact on aircraft design or on our overall test program schedule. We remain fully focused on safety as our highest priority, as we subject the 777X to a rigorous test program prior to first flight."

--

So, I do not see any kind of "lie" from Boeing - and don't have a clue what many of you are complaining about. What appears worse... it seems to show how little many do in fact checking.

Also, given that the fuselage was pressurized to 10 PSI (which was not required) any skin failure would almost certainly involve a huge rush of air out of the aircraft... which would rip unsupported panels adjacent to the failure off (explosive decompression). Which, in my opinion, is what the pictures show. As an engineer with a lot of pressure vessel experience (and having seen pressure vessel failures) - I don't think this looks bad at all.

There are possible failure modes where you would get a small hole with sufficient strength to prevent the explosive decompression of the fuselage.

I am unsure of why Boeing decided to pressurize the fuselage. I don't have enough knowledge of the failure area to be able to predict how such pressurization would affect the failure; although, I doubt that Boeing could have done something that would minimize a possible failure during testing.

Have a great day,
 
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 8:36 pm

2175301 wrote:
What Boeing Said:

https://boeing.mediaroom.com/news-relea ... tem=130500

Boeing Statement on 777X Load Testing

"CHICAGO, September 10, 2019 – During final load testing of the 777X static test airplane, a test which involves bending the wings of the airplane up to a level far beyond anything expected in commercial service, an issue arose that required the team to suspend testing. The testing issue occurred during the final minutes of the test, at approximately 99 percent of the final test loads, and involved a depressurization of the aft fuselage.

The test team followed all safety protocols, and we are conducting a comprehensive root-cause assessment over the coming weeks. The static airplane has been successfully undergoing testing since June, and this was the final test for the static test article. While our root cause assessment continues, at this time we do not expect that this will have a significant impact on aircraft design or on our overall test program schedule. We remain fully focused on safety as our highest priority, as we subject the 777X to a rigorous test program prior to first flight."

--

So, I do not see any kind of "lie" from Boeing - and don't have a clue what many of you are complaining about. What appears worse... it seems to show how little many do in fact checking.

Also, given that the fuselage was pressurized to 10 PSI (which was not required) any skin failure would almost certainly involve a huge rush of air out of the aircraft... which would rip unsupported panels adjacent to the failure off (explosive decompression). Which, in my opinion, is what the pictures show. As an engineer with a lot of pressure vessel experience (and having seen pressure vessel failures) - I don't think this looks bad at all.

There are possible failure modes where you would get a small hole with sufficient strength to prevent the explosive decompression of the fuselage.

I am unsure of why Boeing decided to pressurize the fuselage. I don't have enough knowledge of the failure area to be able to predict how such pressurization would affect the failure; although, I doubt that Boeing could have done something that would minimize a possible failure during testing.

Have a great day,


Good post. As for the question on pressure, I googled and found this link from the 787: https://www.boeing.com/news/frontiers/a ... i_ca05.pdf (emphasis mine)

“We need to get through three of the static-test conditions before we can fly,” said Mark Jenks, vice president of 787 development. The first one is what’s known as “high blow,” which applies 14.9 pounds per square inch (1 kg per square centimeter) internal pressure to test the fuselage structure as a pressure vessel, or its ability to maintain cabin pressurization when flying at altitude. On subsequent test conditions, the internal pressure will be combined with fuselage bending and torsion to simulate worst-case flight maneuvering loads critical for wing/fuselage bending, Jenks said.

The Seattle Times was the one who said door, not Boeing. Unfortunately, this site is covered with fanboys who take far more glee in bashing the respective manufacturers, far more than either manufacturer would ever dream of doing.
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PW100
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 9:00 pm

From the other thread:

bikerthai wrote:
Dang, the Seattle Times article was pretty good. They did own up on the misinformation disseminated when the news broke. They also included this tid-bit.

And the interior of the plane was pressurized beyond normal levels to about 10 pounds per square inch — not typically a requirement for this test, but something Boeing chose to do.


So they over pressured the plane and got a fuselage failure for their effort. :melting:
Anyone out there know how the over pressure would impact the fuselage buckling load? Intuitively you would think it would make it worse, but load interactions are not always intuitive.

bt


If at all, wouldn't fuselage (over)pressure actually help to somewhat alleviate compression stress at the bottom of the fuselage, when bending the fuselage by pulling downward on tail and nose, and upwards on wing? Probably not much, but won't hurt either.
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KlimaBXsst
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 9:36 pm

Transparency is the first sign of a managerial cultural renaissance and shift at Boeing in terms of those recent safety events affecting its narrow- bodies.

A solid Boeing public relations department should and could find ways of capitalizing off of these most recent 777-x certification tests.

I applaud Boeing for allowing these photos to seep out at this time so Boeing may address the incident success and test expectations in depth.
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enzo011
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 10:47 pm

On reflection Boeing didn't mislead with their press release. What seems clear is that the sources used by the journalists didn't give away anything at the time. I doubt Dominic Gates would have made up the cargo door story himself from reading the Boeing press release. So while their official statement was lacking details, unofficially Boeing was sending different information out than the truth. So the next time we hear a source from Boeing telling us the MAX will be ready to fly or the 777X will be good to fly before 2020, take it as a lie as the information is what Boeing wants you to know, not what we hope to be close to the facts.
 
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 10:50 pm

The concern is not whether or not it failed within certification tolerances.
The concern is that it failed at an unexpected point of failure and in a catastrophic way.

You can downplay it by saying that a B777X will never see these loads in actual operation.
But this is factually incorrect.
Aircraft suffer from fatigue. Each cycle that they fly, the airframe becomes weaker and weaker as they undergo all imaginable types of stresses.
So while a brand new airframe can withstand 4.5G, what happens after 100.000 hours and 8.000 cycles, a few hard landings, a few turbulence encounters, airframe repairs right and left, exposure to the elements, engine and other vibrations, cargo loaders banging against the doors' edges, etc...?

So where a brand new airframe can withstand 4.5G, this could be as low as 2G when it reaches 20 years of service as a workhorse.
 
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 11:05 pm

Waterbomber2 wrote:
The concern is not whether or not it failed within certification tolerances.
The concern is that it failed at an unexpected point of failure and in a catastrophic way.

You can downplay it by saying that a B777X will never see these loads in actual operation.
But this is factually incorrect.
Aircraft suffer from fatigue. Each cycle that they fly, the airframe becomes weaker and weaker as they undergo all imaginable types of stresses.
So while a brand new airframe can withstand 4.5G, what happens after 100.000 hours and 8.000 cycles, a few hard landings, a few turbulence encounters, airframe repairs right and left, exposure to the elements, engine and other vibrations, cargo loaders banging against the doors' edges, etc...?

So where a brand new airframe can withstand 4.5G, this could be as low as 2G when it reaches 20 years of service as a workhorse.


Which aircraft in service today did not initially fail one or more certification tests?
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 11:14 pm

Polot wrote:
Carlos01 wrote:
morrisond wrote:
There is an interesting idea in 777X thread that this may be one of the reasons they scrapped the Robotic riveting machine.


What is going to happen to the airframes already built then?

One thing that worries me heavily, is the fact that this hull popped like a balloon at 99%. They tested this once as far as I know. What if they would put the frame through say 5000 cycles of "normal" stress testing, and then give it another go? I doubt it would reach even the 99% before popping.

Given the chance in the upcoming years to fly on a MAX or an X, would I? Probably yes. Would I feel less secure than in a 737-300 or a 777-200? You bet.

It did not pop like a balloon at 99%. It popped like a balloon at 148-149%. The problem is it isn’t allowed to pop like a balloon until after 150%. 150% is chosen precisely to account for years of “normal” stress occurring in service to the frame. This frame has also been undergoing various stress tests before this one. This wasn’t a fresh frame right off the production line.

Agreed, but the A388 had a major wing failure at similar conditions. Boeing over pressurized for the test. Well, they proved that added too much stress.

They will find a fix, reinforce, and move on.

As you note, this was one beat up, at end of life airframe.

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mjoelnir
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 11:20 pm

scbriml wrote:
NeBaNi wrote:
The thing that's been weighing on my mind is that Boeing is scalloping the inside walls on the 777x to create extra space for wider seats at 10-abreast than the current 777. If we approximate the fuselage as being a cylinder, wouldn't having thicker walls help, in terms of being able to hold pressure well? Does anyone know if or think Boeing pressurized the interior to more than the amount needed to see how the thinner walls would hold up?


The scalloped interior walls are not load bearing. They're just the fancy inside bits that cover and hide all the real gubbins behind it. AFAIK, the 77X physical fuselage (before interior fittings are installed) is exactly the same as all other 777s (but a bit longer).


The 777X fuselage is actually changed from the 777. The frames are lower, to give a bigger diameter inside with the same diameter outside.
 
bennett123
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 11:21 pm

IMO, at the present time, and particularly for Boeing, the key is be up front with this sort of thing.

That way, not only do you demonstrate openness, but you are able to explain the facts in the appropriate context.

The most damage is done if you appear evasive or that you are trying to hide something.


The first thing that there disclosure would involve is explaining that the test frame is tested to a level greatly exceeding what will be experienced in service. Secondly, that the failure happened when the frame was subject to a load of almost 50% greater than would be experienced in service and finally that following the test, that the B777X would be strengthened further to ensure that it had an even greater safety margin.

These pictures were bound to get out, perhaps their PR Department were not ahead of the curve.
 
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 11:28 pm

Like others I'm surprised by the over pressurization, I don't understand the point of doing that.

Also I wonder, but this also applies to other failed tests like the A380 one and the 787 one, if it's that easy to reinforce the part that broke : isn't it likely to lead to a weakness elsewhere ?
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DfwRevolution
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 11:45 pm

Baldr wrote:
Polot wrote:
Baldr wrote:
Also, is this the first time that wings being tested at ultimate load (1.5 times the limit load) has resulted in the rupture of the fuselage instead of the wings themselves?

This is not the wing load test you are thinking of.


Which test am I thinking of then?

The test wing of the 777-200 failed at 154% of limit load; the test wing of the C-5A failed at 125% of limit load, while the test wing of the A380 failed at 146% of limit load -- no massive fuselage ruptures occurred.


I recall that the 767 ultimate load test resulted in a failure along the fuselage at the wing-body joint, but I have no concrete evidence to support that claim.

Regarding the topic title: does an airplane *ever* look good after it reaches its limit load? You would have no way to visually distinguish a passed test and a failed test from your eyeball alone. :scratchchin:
I have a three post per topic limit. You're welcome to have the last word.
 
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ER757
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 11:47 pm

I guarantee you the customers are knocking on Boeing's door demanding a re-test or their money back.


Good Lord people - some of the tripe posted here these days defies belief!
As was pointed out by someone upthread, the pictures are exactly what one would expect to see when a pressure vessel fails - when they do it's usually in quite dramatic fashion.
This took place at 148% of ultimate load when they were shooting for 150%. Some people are carrying on as if it happened at 90% and Boeing is getting ready to send their test pilots to certain doom.
Get a grip
Rant over.....carry on
 
caljn
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Wed Nov 27, 2019 11:57 pm

Boeing is under a microscope, which they brought upon themselves. That said I really don't see what the "problem" is here, the result is precisely what the test intended. You correct then move on. Title of this thread is hysterical click bait. .
 
ltbewr
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 12:16 am

This failed within the 'margin of error' but raises issues as to how these structures are designed, unintended consequences of the new design that shows computer modeling vs real life limits and how these structures will be consistently above tolerances in real production.
 
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SheikhDjibouti
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 12:28 am

Carlos01 wrote:
What if they would put the frame through say 5000 cycles of "normal" stress testing, and then give it another go?

Polot wrote:
150% is chosen precisely to account for years of “normal” stress occurring in service to the frame. This frame has also been undergoing various stress tests before this one. This wasn’t a fresh frame right off the production line.

lightsaber wrote:
As you note, this was one beat up, at end of life airframe.

Whoah!, steady on there.

I believe Boeing included the following line in it's statement.
Boeing wrote:
The static airplane has been successfully undergoing testing since June,

I don't see any numbers of tests, nor degree of testing, other than "since June". That only gives as a number of days, with the airframe sitting motionless in an air-conditioned hangar, with or without some artificial environmental and loading factors according to a schedule we don't have. And hence that is about as useless a figure as they come.

We simply don't have any details as to how many years normal service life this testing equates to. :shakehead:

However, if the standard test is 150% when new (or at least fairly new), then that is what we must accept, whether it's Airbus, Boeing. or Wright Flyer.

FWIW we may also legitimately wonder if at the end of a long hard life, the same airframe might only survive a 128.39% over-loading, such as it might encounter whilst flying upside down through a tornado. Again, this concern applies equally whether it is Airbus or Boeing. But if any of us are genuinely worried about that possibility, then we can all pay extra to fly airlines with younger, newer fleets.
Nothing to see here; move along please.
 
dragon6172
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 12:30 am

Waterbomber2 wrote:
The concern is not whether or not it failed within certification tolerances.
The concern is that it failed at an unexpected point of failure and in a catastrophic way.

You dont know that it is an unexpected point of failure. It is possible that this failure came at the location expected to fail first. And the failure certainly would expected to be catastrophic in this sort of test.

The only thing known is that it failed at a lower level of stress than forecasted.
Phrogs Phorever
 
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Polot
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 12:36 am

SheikhDjibouti wrote:
I don't see any numbers of tests, nor degree of testing, other than "since June". That only gives as a number of days, with the airframe sitting motionless in an air-conditioned hangar, with or without some artificial environmental and loading factors according to a schedule we don't have. And hence that is about as useless a figure as they come.


They are not wasting time and space having it sit there doing nothing. While maybe not running 24 hrs they were likely doing testing almost daily. The manufacturers don’t just decide to suddenly run the test to 11- they work their way up to it. All tests requiring the static frame are run prior, this is the last test due to the increased likelihood that the airframe gets significantly damaged (as happened) and the static frame becomes unusable.
 
travelhound
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 1:06 am

Attn Mods:

Can we please have the thread title changed. The use of 'they are bad" in the thread title incorrectly portrays the ultimate load test failure as serious.
This may not be correct, when we consider:
(1) there are reports the failure will have no impact on the certification of the 777X aircraft,
2) failures of this nature have occurred during previous aircraft certification programs,
3) there is no evidence to suggest the engineering and certification of the aircraft has been performed in a compromised manner; and
4) testing of this type is performed to validate and test engineering calculations. This is normal practice in all streams of engineering.

Regards

Travel
 
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BaconButty
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 1:14 am

The A380 wing failure is an interesting one. One of the programme guys came out and said it was due to a late MTOW increase - this was widely ridiculed here, as much like their counterparts in Chicago now, they were at a the nadir of their credibility. Turned out to be true, it was the 569T option available from launch, presumably because early frames were 6T overweight. So basically the wing test failed at 147% of ultimate load iirc, but it was actually pretty close to what was presumably required for a 560T mtow aircraft. They were quick off the mark with the fix too, so were probably expecting it.

Idle speculation but I wonder if something similar is happening on the 77X? It could be bad news if there's an MTOW increase to compensate for being overweight, good news if they found margins elsewhere and made a late decision to add capability. Are the fuselage stress tests dependent on MTOW to the extent the wing tests are? Or are pressurisation loads the key driver?
Down with that sort of thing!
 
AngMoh
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 1:20 am

bennett123 wrote:
IMO, at the present time, and particularly for Boeing, the key is be up front with this sort of thing.

That way, not only do you demonstrate openness, but you are able to explain the facts in the appropriate context.

The most damage is done if you appear evasive or that you are trying to hide something.


The first thing that there disclosure would involve is explaining that the test frame is tested to a level greatly exceeding what will be experienced in service. Secondly, that the failure happened when the frame was subject to a load of almost 50% greater than would be experienced in service and finally that following the test, that the B777X would be strengthened further to ensure that it had an even greater safety margin.

These pictures were bound to get out, perhaps their PR Department were not ahead of the curve.


All these tests are highly confidential. Maybe you say these pictures were bound to get out, but someone violated an NDA doing so. So how can you do PR on something which is not supposed to be public in the first place?
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LH748
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 2:02 am

I'm seriously wondering if Boeing learned anything from their Max disaster and how they handled it in their statements.
Downplaying even the slightest technical issue is exactly what started ruining their reputation. I understand that they don't want negative press about the new 777 but keeping it under cover is reinforcing the doubts in Boeing's trustworthiness.
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rbavfan
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 2:11 am

TTailedTiger wrote:
What exactly do you want Boeing to say? Do you think any company is going to trash talk their own product? Neither Boeing or Airbus (or any other aircraft manufacturer) even take swipes at each other. It was a stress test and and it did exactly what it was intended to do. Find the weak points. If you can do better and promise a flawless result the first time then I'm sure they'd love to hear from you.


The point is not that it failed at 1% below the required limit. Those things are fixed & retested. The point is rather than state if failed and they are going over the location and doing strengthening. But rather that they said a door blew off. Also note in the story about how they are looking at not having to repeat the test. NO you should do the test again on the strengthened frame and make sure it passes the FAA min. Then go from there. Thats what Boeing used to do when they were only Boeing and before the stock market played how many deaths can we withstand if it happens to fail. My veiw of that is those that care more about pure profit than how many could die should have their relatives die in the crash, "if it happens"

I want the old Boeing back, Safety before share value! Because safety builds share value.
 
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Polot
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 2:12 am

rbavfan wrote:
TTailedTiger wrote:
What exactly do you want Boeing to say? Do you think any company is going to trash talk their own product? Neither Boeing or Airbus (or any other aircraft manufacturer) even take swipes at each other. It was a stress test and and it did exactly what it was intended to do. Find the weak points. If you can do better and promise a flawless result the first time then I'm sure they'd love to hear from you.


The point is not that it failed at 1% below the required limit. Those things are fixed & retested. The point is rather than state if failed and they are going over the location and doing strengthening. But rather that they said a door blew off. Also note in the story about how they are looking at not having to repeat the test. NO you should do the test again on the strengthened frame and make sure it passes the FAA min. Then go from there. Thats what Boeing used to do when they were only Boeing and before the stock market played how many deaths can we withstand if it happens to fail. My veiw of that is those that care more about pure profit than how many could die should have their relatives die in the crash, "if it happens"

I want the old Boeing back, Safety before share value! Because safety builds share value.

Boeing never said the door blew off. Please provide the quote where Boeing said the door flew off.
 
rbavfan
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 2:14 am

BlatantEcho wrote:
So there was a failure 3x at what is ever expected in the most extreme real life situation ever.

Why is this stuff news?


Because failing like this 1% below the required FAA limits means you failed the test. Failing should mean it does not get it's cert till the upgrade is fully tested and passes above the requirement line, not below it.
 
rbavfan
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 2:17 am

United1 wrote:
morrisond wrote:
Yes they are expected to fail - I think the bigger part of the story will be Boeing downplaying the story.

Pictures https://www.seattletimes.com/business/b ... uffer_tw_m


It failed within one percent of plan which means they will do a little strengthening here and there and call it a day. This was just another step in the certification process and seems like the airframe did exactly what it was supposed to do...show Boeing where there are any weaknesses at FAR beyond anything you will run into with passenger service.

Airbus had to do the same thing in 2006 when the A380 wings failed at just under their design max.


Yes & I do beleve they had to re test the upgraded unit to get approval.
 
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Polot
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 2:17 am

rbavfan wrote:
United1 wrote:
morrisond wrote:
Yes they are expected to fail - I think the bigger part of the story will be Boeing downplaying the story.

Pictures https://www.seattletimes.com/business/b ... uffer_tw_m


It failed within one percent of plan which means they will do a little strengthening here and there and call it a day. This was just another step in the certification process and seems like the airframe did exactly what it was supposed to do...show Boeing where there are any weaknesses at FAR beyond anything you will run into with passenger service.

Airbus had to do the same thing in 2006 when the A380 wings failed at just under their design max.


Yes & I do beleve they had to re test the upgraded unit to get approval.

You believe incorrectly.
 
Waterbomber2
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 2:19 am

dragon6172 wrote:
Waterbomber2 wrote:
The concern is not whether or not it failed within certification tolerances.
The concern is that it failed at an unexpected point of failure and in a catastrophic way.

You dont know that it is an unexpected point of failure. It is possible that this failure came at the location expected to fail first. And the failure certainly would expected to be catastrophic in this sort of test.

The only thing known is that it failed at a lower level of stress than forecasted.


I know it because Boeing said it: "an issue occurred that required the team to suspend testing" . Translated: we didn't expect that to happen.

I can't say though if overpressurising gives more or less margin in this test. On the one hand it puts tension on the cage structure, but on the other the skin is stiffer and less prone to knicking amd hence should br able to withstand more.

In any case, it's worth studying it and figuring out what the issue is.
 
TTailedTiger
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Re: Pictures surfacing of 777X Sept Test Failure - they are Bad

Thu Nov 28, 2019 2:21 am

rbavfan wrote:
TTailedTiger wrote:
What exactly do you want Boeing to say? Do you think any company is going to trash talk their own product? Neither Boeing or Airbus (or any other aircraft manufacturer) even take swipes at each other. It was a stress test and and it did exactly what it was intended to do. Find the weak points. If you can do better and promise a flawless result the first time then I'm sure they'd love to hear from you.


The point is not that it failed at 1% below the required limit. Those things are fixed & retested. The point is rather than state if failed and they are going over the location and doing strengthening. But rather that they said a door blew off. Also note in the story about how they are looking at not having to repeat the test. NO you should do the test again on the strengthened frame and make sure it passes the FAA min. Then go from there. Thats what Boeing used to do when they were only Boeing and before the stock market played how many deaths can we withstand if it happens to fail. My veiw of that is those that care more about pure profit than how many could die should have their relatives die in the crash, "if it happens"

I want the old Boeing back, Safety before share value! Because safety builds share value.


Did you not catch where the media made a mistake in their reporting? The Washington Times even issued an apology. Boeing did not mislead anyone, it was the media.
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