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Door blows out during ground test on Boeing 777X jet

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Door blows out during ground test on Boeing 777X jet

Old 27th Nov 2019, 17:05
  #121 (permalink)  
 
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Originally Posted by golfyankeesierra View Post
So, the prototype doesn’t meet the certification criteria. So why not let the certification criteria meet the prototype?
It is surprisingly similar to the A-380 wing structure test "The wing of the Airbus A380 static test specimen suffered a structural failure below the ultimate load target during trials in Toulouse earlier this week, but Airbus is confident that it will not need to modify production aircraft." The aircraft was still certified by EASA without repeating the test and you are all happy to fly (on) A-380s.

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Old 27th Nov 2019, 19:05
  #122 (permalink)  
 
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Originally Posted by Ian W View Post
It is surprisingly similar to the A-380 wing structure test "The wing of the Airbus A380 static test specimen suffered a structural failure below the ultimate load target during trials in Toulouse earlier this week, but Airbus is confident that it will not need to modify production aircraft." The aircraft was still certified by EASA without repeating the test and you are all happy to fly (on) A-380s.
​​​​True, very similar!
Now, what is all the secrecy and fuss about a cargo door?
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Old 27th Nov 2019, 20:03
  #123 (permalink)  
 
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Originally Posted by Ian W View Post
It is surprisingly similar to the A-380 wing structure test "The wing of the Airbus A380 static test specimen suffered a structural failure below the ultimate load target during trials in Toulouse earlier this week, but Airbus is confident that it will not need to modify production aircraft." The aircraft was still certified by EASA without repeating the test and you are all happy to fly (on) A-380s.
Thanks for the heads up.
To be fair, one must quote the entire paragraph :
However Garcia says that the failure of the wing below the 1.5 target will require “essentially no modifications” to production aircraft: “This static test airframe has the first set of wings built, and we have refined the structural design for subsequent aircraft due to increased weights etc. We will use this calibration of the FEM to prove the adequacy of the structure on production aircraft.”
They say they have "refined" the structure of the production aircraft, utilizing this test on a pre-prod wing to calibrate their calculations.

Nobody will reproach a failed test to Boeing, except maybe this was to be a demonstration that the previous tests had succeeded.
Also it comes at an unfortunate time, with many other quality/engineering issues cropping up.
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Old 27th Nov 2019, 21:40
  #124 (permalink)  
 
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Finally it's a passenger door that blew open, and the fuselage is a write-off...

https://www.seattletimes.com/busines...r-stress-test/
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Old 28th Nov 2019, 00:58
  #125 (permalink)  
 
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The fuselage buckled and failed just aft of the wing. The door popping out was secondary.
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Old 28th Nov 2019, 06:18
  #126 (permalink)  
 
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To be honest I am surprised this is any worry.

My understanding is that the certification is being subcontracted to Boeing themselves in this day and age (why would the FAA do they their job in the first place? Such an outdated concept) so it should be relatively simple to make this a flying success (pun intended).

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Old 28th Nov 2019, 07:49
  #127 (permalink)  
 
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From the Seattle Times article referred to above:
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Old 28th Nov 2019, 08:06
  #128 (permalink)  
 
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Didn't they want to run it on higher cabin pressure like the 787?
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Old 28th Nov 2019, 13:36
  #129 (permalink)  
 
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Originally Posted by Less Hair View Post
Didn't they want to run it on higher cabin pressure like the 787?
Yes, max diff on the 777X will be a tad under 1 psi higher than its predecessors to give a 6,000' cabin instead of 8,000'.
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Old 28th Nov 2019, 14:09
  #130 (permalink)  
 
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Originally Posted by ThorMos View Post
99.999% of 150% of the way to SFO
Sounds more like a massive overshoot. What's 4,500 km east of SFO?
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Old 28th Nov 2019, 15:26
  #131 (permalink)  
 
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Last week FAA declared testing on the 777X would be tougher.
https://seekingalpha.com/news/352087...n-dickson-says

Too late apparently
https://www.theepochtimes.com/foreig...s_3159634.html

Take into consideration there are no US based 777X customers. There's no way Boeing can again try to get around EASA and other foreign authorities.
Boeing, US congress and FAA can no longer, shoulder to shoulder, work the system. They created this situation themselves, by half-informing, bending & pushing.

They may have been legally be right, pushing congress around for new rulings, streamlining FAA, allow FAA to make exemptions, self regulation.
But they lost trust. & credibility Translate that in free cash flow..

Last edited by keesje; 28th Nov 2019 at 15:49.
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Old 28th Nov 2019, 16:39
  #132 (permalink)  
 
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My understanding is that this was not a fit-for-flight test article that failed and only a test used for extrapolation of some proposed features. Surely the final aircraft configuration will meet all the published requirements.applicable to growth airframes validated by many hours of safe-flight experience.

Before condemning the FAA. and Boeing perhaps the posters could cite specific exceptions to a rule that applies in this case.
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Old 28th Nov 2019, 17:08
  #133 (permalink)  
 
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There are now the conspiracy theories floating around, that BA increased the pressure to prevent the hull from buckling during the test.

Looking at the failure, that was quite the explosion?
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Old 28th Nov 2019, 17:29
  #134 (permalink)  
 
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My understanding is that this was not a fit-for-flight test article that failed and only a test used for extrapolation of some proposed features. Surely the final aircraft configuration will meet all the published requirements.applicable to growth airframes validated by many hours of safe-flight experience.

Before condemning the FAA. and Boeing perhaps the posters could cite specific exceptions to a rule that applies in this case.
Aside from the conspiracy theories, the test is a single event test, not a repetitive or cyclical test.

Slowly bringing the ac up to 1.5 loading really doesnt provide a real test of conditions.
I think there is quite a bit of value in repetitive testing to the typical loading, many issues found in the field may have been avoided. having driven through quite a bit of turbulence, I always wonder about the stresses on the airframe.
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Old 28th Nov 2019, 19:00
  #135 (permalink)  
 
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Originally Posted by lomapaseo View Post
My understanding is that this was not a fit-for-flight test article that failed and only a test used for extrapolation of some proposed features. Surely the final aircraft configuration will meet all the published requirements.applicable to growth airframes validated by many hours of safe-flight experience.

Before condemning the FAA. and Boeing perhaps the posters could cite specific exceptions to a rule that applies in this case.

Geeze- a simple check and knowledge re structural ( static ) test or even videos of 777 test in the mid 90's would make it obvious that the test to 1.5 times design or ' ultimate ' wouild reveal that the article under test was NOT designated or assembled for eventual flight. Airbus does different - but Boeing has never used the structural test article for flight. Usually the structural test article is amoung the first three airframes built. One for structural, one for fatigue test, and one for flight. For example, the first 767 built was for flight test and later sold to United. The second was for static test, the third for fatigue test. By the time of static test, about a half dozen 767 were already in various stages of assembly.
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Old 28th Nov 2019, 21:46
  #136 (permalink)  
 
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Originally Posted by India Four Two View Post
From the Seattle Times article referred to above:
Oh boy ... So
the door blew out
is the new
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Old 28th Nov 2019, 21:47
  #137 (permalink)  
 
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Originally Posted by turbidus View Post
Aside from the conspiracy theories, the test is a single event test, not a repetitive or cyclical test.

Slowly bringing the ac up to 1.5 loading really doesnt provide a real test of conditions.
I think there is quite a bit of value in repetitive testing to the typical loading, many issues found in the field may have been avoided. having driven through quite a bit of turbulence, I always wonder about the stresses on the airframe.
Apples and Oranges. The test is question is 'ultimate load' - stress to 1.5x the max anticipated load and often to failure even if it's higher than the 1.5x requirement. A different airframe will be used for fatigue life testing, running the airframe through tens of thousands of simulated flight cycles - a test that takes many months to complete. That being said, fatigue life testing is a bit of a black art - accurately simulating actual flight loads is non-trivial.

BTW, for all the Boeing bashing going on, I notice this little tidbit apparently escaped notice:
At the same time, the fuselage was bent downward at the extreme front and aft ends with millions of pounds of force. 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.
In other words, Boeing had previously done the 1.5x pressurization test - and passed. Then, although it's not a regulatory requirement, they again pressurized the fuselage to 1.5x when they did the wing ultimate load test - when it failed at 99% of target.
Oh, and for all the bitching about 'self certification' - there were six FAA people observing the test when the failure occurred.

Oh Grebe, the first 767 - VA001 - was not sold to United. It was initially kept by Boeing for use as a flying test bed, before being modified to the AOA (Airborne Optical Adjunct) test aircraft as part of Reagan's 'Star Wars' initiative.



Last edited by tdracer; 28th Nov 2019 at 22:00.
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Old 28th Nov 2019, 22:23
  #138 (permalink)  
 
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Originally Posted by tdracer View Post
Oh, and for all the bitching about 'self certification' - there were six FAA people observing the test when the failure occurred.
OK, but that doesn't actually say anything, at all, about the reality of delegated certification authority, which is an undeniable, inarguable reality -- whatever you think of it.

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Old 28th Nov 2019, 22:53
  #139 (permalink)  
 
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Originally Posted by tdracer View Post
BTW, for all the Boeing bashing going on, I notice this little tidbit apparently escaped notice:

In other words, Boeing had previously done the 1.5x pressurization test - and passed. Then, although it's not a regulatory requirement, they again pressurized the fuselage to 1.5x when they did the wing ultimate load test - when it failed at 99% of target.
That much was reported soon after the event:

Door blows off Boeing 777X during stress test

"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.

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."

Though the combined test was subsequently denied by another poster

Originally Posted by Smythe View Post
Point of clarification here.

The wings were NOT being tested at the SAME TIME as the cabin pressure test.

They were simply doing the cabin pressure test while it was on the stand. (which was prudent, given the results)
who subsequently declined to cite any evidence for that assertion.
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Old 28th Nov 2019, 23:47
  #140 (permalink)  
 
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Originally Posted by medod View Post
I wonder why Boeing bothered doing a non-FAA test then. And why FAA staff were there. Shits and giggles?
The regulations spell out the minimum requirements - it's always acceptable to do cert tests that exceed those minimum requirements.

Originally Posted by OldnGrounded View Post
OK, but that doesn't actually say anything, at all, about the reality of delegated certification authority, which is an undeniable, inarguable reality -- whatever you think of it.
The reality of delegated authority is that the FAA picks and chooses what is delegated and what it retained, whatever you might think of it in your reality.

The level of ignorance of certification requirements, testing, and procedures exhibited by some of the critics on this forum is rather disturbing.
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