kalvado
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 4:57 pm

OldAeroGuy wrote:
kalvado wrote:
OldAeroGuy wrote:

Ahh.. How soon we forget.

https://www.flightglobal.com/news/artic ... ad-204716/

Which is the more difficult problem to solve, wing structure or a cargo door latch/structure?

Let's see. A380 failed too early in an ultimate load test to destruction. Early failure is, of course, a problem, but it is a 2% error after all - and test artifact is a write-off either way
Is there any indication 777X was undergoing a destruction test to determine safety margin? I am pretty sure that would be explicitly mentioned a few times by now - but quazi-official "policy statement" above is pretty mum, and no official response from Boeing. Did they come to 2% within ultimate load during routine test, or this was a maximum load test - and that would mean whooping 50% error and no safety margin exists in the design?
This is a fatigue test frame; as far as I understand those are used for continuing test after the aircraft enters service - so destructive test is pretty doubtful to begin with.

Besides, are you sure this is a latch failure - and not a catastrophic structural failure of primary load-bearing structures? We all hope for the best....


Please read the referenced article.

ttps://simpleflying.com/boeing-777x-st ... l-testing/ quotes a Boeing spokesman:

"During final load testing on the 777X static test airplane, the team encountered an issue that required suspension of the test. The testing conditions were well beyond any load expected in commercial service. The event is under review and the team is working to understand the root cause. Final load testing is the last in a series of tests that Boeing has been conducting on this full-scale test airplane over the past several months."

- This was the static test airplane, not the fatigue airplane.
- Final load testing is to 150% of limit load, it doesn't need to be to destruction.
- The door failure could be due to a latching failure or structural failure. It's still easier to solve than a wing structural failure.

Glass half full or glass half empty?
We don't really know anything. Can be a latch failure at 149.95% of load limit, can be a structural failure at 102%. I am not actually aware of what the load limit could be; stuck outflow valve maybe? People throw around numbers that A is testing to 2x in-service maximum.
Overall, the issue can be resolved by analysis and a bit of reinforcement designed within a week, or it can require a dedication of another frame to testing due to structural damage to test article and still having to pass the test (which would be worse than A380 case). Neither you nor I are privileged to Boeing test data (and maybe it is still being processed). There are people who consider the best-case scenario only, I am looking at both ends of the spectrum. With Boeing recent history we can only pray things are closer to a mild problem.
 
WIederling
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 4:58 pm

OldAeroGuy wrote:
WIederling wrote:
OldAeroGuy wrote:
Which is the more difficult problem to solve, wing structure or a cargo door latch/structure?


"wings not coming off" has been mastered earlier than "doors not blowing out" afair.


While I'd prefer no failures, a cargo door failure is preferable to a wing failure.


In flight yes.
during certification it is a wash.
Murphy is an optimist
 
Checklist787
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 5:15 pm

WIederling wrote:
OldAeroGuy wrote:
WIederling wrote:

"wings not coming off" has been mastered earlier than "doors not blowing out" afair.


While I'd prefer no failures, a cargo door failure is preferable to a wing failure.


In flight yes.
during certification it is a wash.


What is the difference?
A cargo door failure is ALWAYS preferable to a wing failure!
Last edited by Checklist787 on Sun Sep 08, 2019 5:17 pm, edited 1 time in total.
 
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keesje
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 5:15 pm

It was final maximum load testing. Nobody says the door flew at or close to maximum load. Maybe it was at 117%. We don't know yet.
"Never mistake motion for action." Ernest Hemingway
 
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Stitch
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 5:28 pm

kalvado wrote:
Is there any indication 777X was undergoing a destruction test to determine safety margin?


According to the reports, articles and statements, the test was performed at Ultimate Load, which is 150% of Limit Load (which itself is equal to what the OEM calculates an airframe could ever possibly experience in actual service). So somewhere between 100 and 150% is where it failed as Boeing would have no reason to go beyond 150%.
 
kalvado
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 5:31 pm

Stitch wrote:
kalvado wrote:
Is there any indication 777X was undergoing a destruction test to determine safety margin?


According to the reports, articles and statements, the test was performed at Ultimate Load, which is 150% of Limit Load (which itself is equal to what the OEM calculates an airframe could ever possibly experience in actual service). So somewhere between 100 and 150% is where it failed as Boeing would have no reason to go beyond 150%.

Do you have any link using the word "ultimate"?
I've seen final load testing being mentioned, but not "ultimate"
 
oschkosch
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 5:38 pm

Checklist787 wrote:
WIederling wrote:
OldAeroGuy wrote:

While I'd prefer no failures, a cargo door failure is preferable to a wing failure.


In flight yes.
during certification it is a wash.


What is the difference?
A cargo door failure is ALWAYS preferable to a wing failure!
excuse my ignorance, but have they done the wing tests on this plane yet? And what the foldable wing tips? How are they tested?

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Revelation
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 5:38 pm

Wow, a total tempest in a teapot.
A380: Problem analyzed and addressed, never an issue in service
777X: Problem analyzed and addressed, never an issue in service
Wake up to find out that you are the eyes of the world
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kalvado
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 5:41 pm

Revelation wrote:
Wow, a total tempest in a teapot.
A380: Problem analyzed and addressed, never an issue in service
777X: Problem analyzed and addressed, never an issue in service

True. Question is if it will delay the program - and for how long; and how much it is going to cost.
 
Olddog
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 5:43 pm

Revelation wrote:
Wow, a total tempest in a teapot.
A380: Problem analyzed and addressed, never an issue in service
777X: Problem analyzed and addressed, never an issue in service


Wow, the 777x has no in service data, no analyze can be made and problem can't be solved in 24 h.

We don't know at what load the door failed but if it was very close to the 150 % threshold, Boeing would have let the whole word know by now.
When UK was in it wanted a lot of opt-outs, now it is out it wants opt-ins
 
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par13del
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 5:53 pm

Lets go with worst case scenario since Boeing has said nothing, it was at 50% load, if it was between 100 to 150 as Stitch point out Boeing would not have said loads not expected to ..........
 
kalvado
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 6:03 pm

par13del wrote:
Lets go with worst case scenario since Boeing has said nothing, it was at 50% load, if it was between 100 to 150 as Stitch point out Boeing would not have said loads not expected to ..........

Very unrealistic.
This was the final test - and there should be a series of tests before that one with increasing loads, and measurements taken to verify the model Boeing has.
So, on one hand, this means that 50% mark should be tested a while ago, and on the other hand, Boeing had plenty of knowledge and had certain expectations about what is going on.
That is why a significant failure looks strange from my perspective.
 
stresskid
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 6:10 pm

To clarify, the 1.5 ultimate load factor does not apply to cabin pressure. The factor for cabin pressure is 1.33, and we don't know whether or not Boeing chooses to design and test to a higher pressure.
 
kalvado
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 6:22 pm

stresskid wrote:
To clarify, the 1.5 ultimate load factor does not apply to cabin pressure. The factor for cabin pressure is 1.33, and we don't know whether or not Boeing chooses to design and test to a higher pressure.

What is the base value for that 1.33 factor? Is it normal flight pressure differential, os something else?
From my perspective, pressure vessel must be protected by rupture membranes calibrated for pressure above the normal differential, and then safety factor should be on top of those membranes limit.
 
stresskid
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 6:26 pm

kalvado wrote:
stresskid wrote:
To clarify, the 1.5 ultimate load factor does not apply to cabin pressure. The factor for cabin pressure is 1.33, and we don't know whether or not Boeing chooses to design and test to a higher pressure.

What is the base value for that 1.33 factor? Is it normal flight pressure differential, os something else?
From my perspective, pressure vessel must be protected by rupture membranes calibrated for pressure above the normal differential, and then safety factor should be on top of those membranes limit.

It's 1.33x the "maximum relief valve setting", so not the normal differential I guess, but how different, I'm not sure.

Source: https://www.law.cornell.edu/cfr/text/14/25.365
 
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enzo011
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 7:15 pm

I have a question, I believe the 777X changed the window size from the 777, what effect would this have had and would it be related?
 
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SEPilot
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 7:45 pm

enzo011 wrote:
I have a question, I believe the 777X changed the window size from the 777, what effect would this have had and would it be related?

Since this was a cargo door, the windows would have no effect. Neither would the thinner sidewalls since the cargo door is below the floor and the windows and thinner sidewalls are above it. The only relevant change is changing the cabin altitude from 8,000 ft to 6,000 ft.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
Checklist787
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 8:15 pm

Revelation wrote:
Wow, a total tempest in a teapot.
A380: Problem analyzed and addressed, never an issue in service
777X: Problem analyzed and addressed, never an issue in service


Totally agree!

I do not understand why there are some who continue ...
 
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Stitch
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 8:18 pm

kalvado wrote:
Do you have any link using the word "ultimate"?
I've seen final load testing being mentioned, but not "ultimate"


Well the final test is the Ultimate Load test, so...
 
trex8
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 8:21 pm

Checklist787 wrote:
Revelation wrote:
Wow, a total tempest in a teapot.
A380: Problem analyzed and addressed, never an issue in service
777X: Problem analyzed and addressed, never an issue in service


Totally agree I do not understand why there are some who continue ...


I'm so grateful we have people here who have ESP and can predict the future perfectly. I'm sure its not an issue that B can't fix, besides they'll have months to fix it before the first flight!
 
WIederling
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 9:04 pm

Revelation wrote:
Wow, a total tempest in a teapot.
A380: Problem analyzed and addressed, never an issue in service
777X: Problem <you are here> analyzed and addressed, never an issue in service


The door blew out.
Nothing beyond that fact is known at the moment.
( at least to the wider public posting here.)
Murphy is an optimist
 
tomcat
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 9:06 pm

Finn350 wrote:
Just for comparison, here is a video from the A350 static ground testing including mechanical load and pressurization testing. On an A350, the pressurization is tested up to 1.3 bar according to the video.
https://youtu.be/B74_w3Ar9nI


Haha, you should have extended the quote (2'14'' and on):
More than 1.3 bar, it's like a bomb. If ever a cargo door is opening, we can damage the complete building up to detrimental effect.
It's like this guy had a premonition but luckily for Airbus it wasn't applicable to the A350.
 
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Erebus
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Re: Boeing 777X Testing Thread - 2019

Sun Sep 08, 2019 10:09 pm

OldAeroGuy wrote:
WIederling wrote:
OldAeroGuy wrote:
Which is the more difficult problem to solve, wing structure or a cargo door latch/structure?


"wings not coming off" has been mastered earlier than "doors not blowing out" afair.


While I'd prefer no failures, a cargo door failure is preferable to a wing failure.


In theory, yes I can agree. But in reality, a wing failure on a large modern airliner in normal service is unheard of. Cargo door failures, however, have had multiple fatal consequences.
 
Max Q
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 12:41 am

trex8 wrote:
There was that CI 747-400F whose nose door blew open damaging the cockpit area during a pressurization test on an in production model. https://www.seattlepi.com/business/arti ... 197536.php




That’s the incident I was referring to

I think that aircraft was for China Airlines and I believe they may have refused delivery on it despite Boeing repairing the airframe app
The best contribution to safety is a competent Pilot.


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RickNRoll
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 2:26 am

SEPilot wrote:
enzo011 wrote:
I have a question, I believe the 777X changed the window size from the 777, what effect would this have had and would it be related?

Since this was a cargo door, the windows would have no effect. Neither would the thinner sidewalls since the cargo door is below the floor and the windows and thinner sidewalls are above it. The only relevant change is changing the cabin altitude from 8,000 ft to 6,000 ft.

My understanding is that the construction of the hull will be the same all the way around. That has been changed.
 
JayinKitsap
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 3:25 am

zeke wrote:
JayinKitsap wrote:
What isn't known is whether the test pressure when the door failed was below, at, or above the required test pressure. Often in structures the test continues to failure. It is a good way to find what margin remains, if only a few percent not worth mining. But if it is like 10% over, it can be used for a MTOW increase or similar.


I think Boeing tests every production aircraft built beyond the normal maximum by increasing the internal pressure with the aircraft sealed.


I agree that Boeing tests every production aircraft by internal pressure, but I don't know to what specific pressure. Usually an operational test would be to about 110% of design pressure. It is a great way to test seals, joints, door hinges and latches, etc. If it holds pressure for 5 to 10 min without falloff the test is good. A test to ultimate (the 150% of the the maximum design pressure, which as noted above is like 1.3 x the operating pressure (cabin pressure less pressure at altitude.) Usually in structures and piping systems tests past 125%, in particular of materials have exceeded yield stress, the article would not be returned to service. There is the potential of damage once past yield.
 
Theseus
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 6:35 am

In fact, what makes me the most sad about this is that I do not expect much details to be ever released. Am I wrong ?
Pictures and full stories would be fascinating to read, as about all engineering issues.
 
cpd
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 1:59 pm

OldAeroGuy wrote:
WIeder

ling wrote:
OldAeroGuy wrote:
Which is the more difficult problem to solve, wing structure or a cargo door latch/structure?


"wings not coming off" has been mastered earlier than "doors not blowing out" afair.


While I'd prefer no failures, a cargo door failure is preferable to a wing failure.


Thanks to the person who posted this as a separate topic (and had the moderator lock it). I wouldn’t have seen this otherwise buried in a mega topic with a broad title.

It’s not ideal having this occur while other planes have already been built.
 
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zkojq
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 2:33 pm

Max Q wrote:
I believe this happened to a 747 freighter where the forward cargo
door blew off the aircraft during pressure testing ?



trex8 wrote:
There was that CI 747-400F whose nose door blew open damaging the cockpit area during a pressurization test on an in production model. https://www.seattlepi.com/business/arti ... 197536.php


Max Q wrote:
I think that aircraft was for China Airlines and I believe they may have refused delivery on it despite Boeing repairing the airframe app



LN1372 delivered to China Airlines Cargo as B-18722. Spent the first decade of its life painted white due to superstitions of employees or something.

https://m.planespotters.net/airframe/Bo ... s/MdROIj0e

Revelation wrote:
777X: Problem analyzed and addressed, never an issue in service

I hope so.
First to fly the 787-9
 
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zkojq
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 2:36 pm

morrisond wrote:
Isn't the 777X going to be flying with a lower Cabin Altitude? Aren't they setting it lower like the 787?

Wouldn't that require testing at a higher Pressure Differential than they did when they first certified the 777?

Is that why maybe the Cargo door failed?

That should be an easy fix.


Why is it an easy fix if more pressure was put on a component and it failed? :scratchchin:
First to fly the 787-9
 
iamlucky13
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 6:01 pm

stresskid wrote:
It's 1.33x the "maximum relief valve setting", so not the normal differential I guess, but how different, I'm not sure.

Source: https://www.law.cornell.edu/cfr/text/14/25.365


Thank you for providing both the actual criteria and the authoritative source. Excellent contribution to the discussion.

mjoelnir wrote:
The worst problem for Boeing could be the number of frames already built, all to be reworked with the changes. I start to question how sensible it is, to start production of customer frames, before you have finished certain tests. In this case the static tests and parts of the flight testing. The dynamic test run to long to wait for the final results.
In this case the rework on the production frames has to wait for the redesign and retesting. I assume flight test can commence before the new design regarding the cargo door problem is finished.


Aircraft development schedules already factor in time to incorporate changes determined to be necessary during certification. The first 777X to be delivered could well be months away from even starting assembly.

There is a cost to retrofitting aircraft versus waiting until the certification configuration is set in stone, but the cost of creating a production system, qualifying it to produce an aircraft, and then leaving everyone sitting around doing nothing for a year or more is usually even higher.
 
morrisond
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 6:16 pm

CNBC just reported that Boeing stated the failed door will not impact their schedule - which is still First Flight beginning of 2020 with First Customer Delivery by end of 2020.
 
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seabosdca
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 7:59 pm

morrisond wrote:
CNBC just reported that Boeing stated the failed door will not impact their schedule - which is still First Flight beginning of 2020 with First Customer Delivery by end of 2020.


But it might make the intervening time significantly more hectic for the fuselage team!
 
Spetsnaz55
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 8:09 pm

iamlucky13 wrote:
stresskid wrote:
It's 1.33x the "maximum relief valve setting", so not the normal differential I guess, but how different, I'm not sure.

Source: https://www.law.cornell.edu/cfr/text/14/25.365


Thank you for providing both the actual criteria and the authoritative source. Excellent contribution to the discussion.

mjoelnir wrote:
The worst problem for Boeing could be the number of frames already built, all to be reworked with the changes. I start to question how sensible it is, to start production of customer frames, before you have finished certain tests. In this case the static tests and parts of the flight testing. The dynamic test run to long to wait for the final results.
In this case the rework on the production frames has to wait for the redesign and retesting. I assume flight test can commence before the new design regarding the cargo door problem is finished.


Aircraft development schedules already factor in time to incorporate changes determined to be necessary during certification. The first 777X to be delivered could well be months away from even starting assembly.

There is a cost to retrofitting aircraft versus waiting until the certification configuration is set in stone, but the cost of creating a production system, qualifying it to produce an aircraft, and then leaving everyone sitting around doing nothing for a year or more is usually even higher.



Huh? The 4th or 5th Emirates 777x is getting final body join right now
 
StTim
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 09, 2019 8:34 pm

RickNRoll wrote:
SEPilot wrote:
enzo011 wrote:
I have a question, I believe the 777X changed the window size from the 777, what effect would this have had and would it be related?

Since this was a cargo door, the windows would have no effect. Neither would the thinner sidewalls since the cargo door is below the floor and the windows and thinner sidewalls are above it. The only relevant change is changing the cabin altitude from 8,000 ft to 6,000 ft.

My understanding is that the construction of the hull will be the same all the way around. That has been changed.



The have changed the ribs in the passenger area to be lower profile (intrude into the cabin area less) in order to create the extra width.

This will change the stress paths. If (and I doubt it) this was the cause then it could’ve substantial redesign. I truly hope this is not the case.
 
kevin5345179
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Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 5:01 am

Finn350 wrote:
Just for comparison, here is a video from the A350 static ground testing including mechanical load and pressurization testing. On an A350, the pressurization is tested up to 1.3 bar according to the video.
https://youtu.be/B74_w3Ar9nI


interesting
according aviation week, 787 only tested up to 14.9 psi (1.03 bar)

https://aviationweek.com/commercial-avi ... 08ab35500b
 
mjoelnir
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Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 7:22 am

Interesting this discussion. A cargo door has blown out on the 777x static test frame. Boeing has stopped the testing to research whet has happened. Nothing is known, but one thing. This will not have any influence on the test flight and delivery schedule of the 777-9.

And some posters here take Boeing declaration about time frames regarding test flights and EIS of the 777-9 still serious. :sarcastic:
 
Noshow
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Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 7:49 am

Boeing has become so quiet about everything. Is it just me or do all the rumors start to become wilder and wilder since then? How about some more information again from Boeing itself? Who is behind this hush strategy? It does no good. This goes for the MAX progress as well.
 
WIederling
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Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 7:53 am

mjoelnir wrote:
Interesting this discussion. A cargo door has blown out on the 777x static test frame. Boeing has stopped the testing to research whet has happened. Nothing is known, but one thing. This will not have any influence on the test flight and delivery schedule of the 777-9.

And some posters here take Boeing declaration about time frames regarding test flights and EIS of the 777-9 still serious. :sarcastic:

They don't lie. never. :-)
But the background is held out of focus.
Go back to the 787:
Take away any _single_ issue and nothing would have changed in the general time line of 787 progress towards EIS.

Noteworthy that "foreign" hickups were regularly moved up front to "give reasons for delays".
And the same for the MAX: ... return to service only held back by EASA denying their nod to go ahead.
Murphy is an optimist
 
Oykie
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Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 8:15 am

WIederling wrote:
mjoelnir wrote:
Interesting this discussion. A cargo door has blown out on the 777x static test frame. Boeing has stopped the testing to research whet has happened. Nothing is known, but one thing. This will not have any influence on the test flight and delivery schedule of the 777-9.

And some posters here take Boeing declaration about time frames regarding test flights and EIS of the 777-9 still serious. :sarcastic:

They don't lie. never. :-)
But the background is held out of focus.
Go back to the 787:
Take away any _single_ issue and nothing would have changed in the general time line of 787 progress towards EIS.

Noteworthy that "foreign" hickups were regularly moved up front to "give reasons for delays".
And the same for the MAX: ... return to service only held back by EASA denying their nod to go ahead.


I can’t seem to recall that Boeing has blamed EASA for the MAX still being grounded? They have not sent their fix to approval as far as I know
Dream no small dream; it lacks magic. Dream large, then go make that dream real - Donald Douglas
 
trijetsonly
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Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 9:00 am

Spetsnaz55 wrote:
Huh? The 4th or 5th Emirates 777x is getting final body join right now


That doesn't necessarily mean that they are going to be the first to be delivered.
Happy Landings
 
Opus99
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Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 9:44 am

morrisond wrote:
CNBC just reported that Boeing stated the failed door will not impact their schedule - which is still First Flight beginning of 2020 with First Customer Delivery by end of 2020.

They sure seem fixated on this end of 2020 EIS. I don’t know what magic they plan on performing to ensure that.
 
mjoelnir
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Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 9:52 am

trijetsonly wrote:
Spetsnaz55 wrote:
Huh? The 4th or 5th Emirates 777x is getting final body join right now


That doesn't necessarily mean that they are going to be the first to be delivered.


The point was about necessary expensive rework, by producing production frames early.
 
justloveplanes
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Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 9:55 am

SEPilot wrote:
enzo011 wrote:
I have a question, I believe the 777X changed the window size from the 777, what effect would this have had and would it be related?

Since this was a cargo door, the windows would have no effect. Neither would the thinner sidewalls since the cargo door is below the floor and the windows and thinner sidewalls are above it. The only relevant change is changing the cabin altitude from 8,000 ft to 6,000 ft.


What about the AlLi Fuselage? Does that material have different bending/brittleness under load? Another factor maybe?

And the top fuselage design changes can transfer more bending loads ETC. to the bottom. So it may be a legacy door hinge design needs rework.

If the main tube is okay, it would seem an updated door design should not be a big issue.
 
asdf
Posts: 372
Joined: Tue Mar 18, 2014 12:03 am

Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 10:05 am

justloveplanes wrote:
If the main tube is okay, it would seem an updated door design should not be a big issue.


With our current knowledge of FAA's certification procedures with boeing ("... you do not have to document your results, you just have to say whether it's OK or not ..."): Is it possible that they never did such a pressure test for the original 777 framework?

That the FAA has requested one now, simply due to the current MAX / EASA developments?
It has been said several times that this pressure test should have been done much earlier according to the 777X schedule ...
 
WIederling
Posts: 8744
Joined: Sun Sep 13, 2015 2:15 pm

Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 10:26 am

Oykie wrote:
I can’t seem to recall that Boeing has blamed EASA for the MAX still being grounded? They have not sent their fix to approval as far as I know


Obviously they would not try that.
But who inserts the funny rumors "ready to go, just EASA hanging back"
into the discussions ( media, specialist sites like here, .. )
to the potential benefit of Boeing's publicly perceived performance ?
Q3 reports are coming up. you have to prepare our bedding accordingly.
Murphy is an optimist
 
User avatar
zkojq
Posts: 3831
Joined: Fri Sep 02, 2011 12:42 am

Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 11:03 am

mjoelnir wrote:
Interesting this discussion. A cargo door has blown out on the 777x static test frame. Boeing has stopped the testing to research whet has happened. Nothing is known, but one thing. This will not have any influence on the test flight and delivery schedule of the 777-9.

And some posters here take Boeing declaration about time frames regarding test flights and EIS of the 777-9 still serious. :sarcastic:


I'm most surprised at the people here who speak about the matter as if a cargo door exploding during testing is somehow a good thing. :eyepopping:
First to fly the 787-9
 
asdf
Posts: 372
Joined: Tue Mar 18, 2014 12:03 am

Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 11:18 am

zkojq wrote:
mjoelnir wrote:
Interesting this discussion. A cargo door has blown out on the 777x static test frame. Boeing has stopped the testing to research whet has happened. Nothing is known, but one thing. This will not have any influence on the test flight and delivery schedule of the 777-9.

And some posters here take Boeing declaration about time frames regarding test flights and EIS of the 777-9 still serious. :sarcastic:


I'm most surprised at the people here who speak about the matter as if a cargo door exploding during testing is somehow a good thing. :eyepopping:


Well, actually it is not THAT bad
Because it proofs that test and certification works

What is kinda smelling is that a part failed that has been already certified till years
it seems like there are no modifikations on the modules at that frame aerea

why didnt it fail at the 777 test years ago?
 
User avatar
zkojq
Posts: 3831
Joined: Fri Sep 02, 2011 12:42 am

Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 12:04 pm

asdf wrote:
zkojq wrote:
mjoelnir wrote:
Interesting this discussion. A cargo door has blown out on the 777x static test frame. Boeing has stopped the testing to research whet has happened. Nothing is known, but one thing. This will not have any influence on the test flight and delivery schedule of the 777-9.

And some posters here take Boeing declaration about time frames regarding test flights and EIS of the 777-9 still serious. :sarcastic:


I'm most surprised at the people here who speak about the matter as if a cargo door exploding during testing is somehow a good thing. :eyepopping:


Well, actually it is not THAT bad
Because it proofs that test and certification works

What is kinda smelling is that a part failed that has been already certified till years
it seems like there are no modifikations on the modules at that frame aerea

why didnt it fail at the 777 test years ago?


Older 777s have higher cabin altitudes which means less differential pressure compared to the new 777-9x with it's lower cabin altitude. Higher differential pressure means more stress on the fuselage, windows, doors etc so that could be a reason - though I wouldn't want to jump to conclusions, especially when we don't know much first hand about what happened.
First to fly the 787-9
 
justloveplanes
Posts: 996
Joined: Thu Jul 08, 2004 5:38 am

Re: Boeing 777X Testing Thread - 2019

Tue Sep 10, 2019 12:08 pm

asdf wrote:
justloveplanes wrote:
If the main tube is okay, it would seem an updated door design should not be a big issue.


With our current knowledge of FAA's certification procedures with boeing ("... you do not have to document your results, you just have to say whether it's OK or not ..."): Is it possible that they never did such a pressure test for the original 777 framework?

That the FAA has requested one now, simply due to the current MAX / EASA developments?
It has been said several times that this pressure test should have been done much earlier according to the 777X schedule ...


If is was a simultaneous condition as part of the ultimate load test for checking a worse case scenario, then it could only be done now.

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