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scbriml
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 2:38 pm

Revelation wrote:
For me, one key takeaway was: “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 programme schedule".


Of course. That's what Boeing will continue to say until they announce an impact on design or the test schedule. :spin:
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9Patch
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 3:04 pm

SomebodyInTLS wrote:
I think he's trying to say that AlLi is just another aluminium alloy, like the typical 2024 and 7075 alloys (with added copper, magnesium, iron, chrome, etc.) used for most of the 20th century. I.e. AlLi can ALSO be referred to as "aluminium". Aircraft have never been made from *pure* aluminium...


What confused me was Aviation Week writing the 77X fuselage is constructed of standard aluminum.

It sounds like there's no such thing as standard aluminum. It would have been much clearer if they had simply stated the 77X fuselage is constructed of Al-Li.

I found an interesting article on the use of aluminum alloys in aircraft construction:
https://www.experimentalaircraft.info/a ... uminum.php
 
kalvado
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 3:08 pm

9Patch wrote:
SomebodyInTLS wrote:
I think he's trying to say that AlLi is just another aluminium alloy, like the typical 2024 and 7075 alloys (with added copper, magnesium, iron, chrome, etc.) used for most of the 20th century. I.e. AlLi can ALSO be referred to as "aluminium". Aircraft have never been made from *pure* aluminium...


What confused me was Aviation Week writing the 77X fuselage is constructed of standard aluminum.

It sounds like there's no such thing as standard aluminum. It would have been much clearer if they had simply stated the 77X fuselage is constructed of Al-Li.

I found an interesting article on the use of aluminum alloys in aircraft construction:
https://www.experimentalaircraft.info/a ... uminum.php

"Standard aluminum" can mean "not carbon composite, like 787"
Al-Li, although a (relatively) modern compound, is still Al. And differentiating Al-Li from Al-Zn-Cu or Al-Si is a much finer level of detail
 
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SomebodyInTLS
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 3:14 pm

9Patch wrote:
SomebodyInTLS wrote:
I think he's trying to say that AlLi is just another aluminium alloy, like the typical 2024 and 7075 alloys (with added copper, magnesium, iron, chrome, etc.) used for most of the 20th century. I.e. AlLi can ALSO be referred to as "aluminium". Aircraft have never been made from *pure* aluminium...


What confused me was Aviation Week writing the 77X fuselage is constructed of standard aluminum.

It sounds like there's no such thing as standard aluminum. It would have been much clearer if they had simply stated the 77X fuselage is constructed of Al-Li.


So then I would second-guess them meaning "aluminium rather than composites"...

You're correct that there's no such thing as "standard aluminium" in aircraft structures, although 2024-T3 was more or less a de-facto standard during the glory years of the jet age.
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ikramerica
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 3:33 pm

747classic wrote:
Most of us (incl. myself) initially got the impression that the failure occured during the combined max wingflex and pressurized fuselage test.
However the failure occurred according the Aviation week article of Guy Norris during the (first) fuselage high blow test. (without wing load)
See : https://aviationweek.com/commercial-avi ... re-failure
According Boeing at 99% of the max.load of 150% differential pressure (14,9 psi) the door failure occured.
The problem Boeing is facing that the next test (150% wingload + pressurized fuselage) cannot be performed before the door or door frame structure has been repaired (and reinforced).
But seen the extra time needed to modify the GE9X engines Boeing doesn't anticipate an extra delay due this issue.
We will see how much time is needed for fixing the static test fuselage.

For an explanation of the different static test of the 787, see : https://www.boeing.com/news/frontiers/a ... i_ca05.pdf

Considering the 777x is meant to have a higher air pressure, could the “fix” be dropping that pressure slightly so that 148% becomes 152%? Add 100 feet to the internal altitude?
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Eyad89
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 4:05 pm

Revelation wrote:

For me, one key takeaway was: “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 programme schedule".


The part that stands out is that the root cause of the problem is still being investigated? It is hard to get an exact meaning from an official statement, but he did NOT say that the root cause is already identified.

Let’s see if Boeing gets its fix before GE does.
 
musman9853
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 4:17 pm

scbriml wrote:
Revelation wrote:
For me, one key takeaway was: “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 programme schedule".


Of course. That's what Boeing will continue to say until they announce an impact on design or the test schedule. :spin:


theyre already significantly behind b/c the GE9X delays. it's completely probable they'll fix this issue before ge fixes thier engine.
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 5:58 pm

Revelation wrote:
https://www.flightglobal.com/news/articles/boeing-downplays-impact-of-777x-load-test-issue-460780/ has some updates via a Boeing representative.

I'm not sure if it adds or reduces clarity to what we know already.

For me, one key takeaway was: “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 programme schedule".


Based on this, it was the final test of the static frame after all, wings were bent to the maximum 150 % load and the fuselage was pressurized. All the previous reporting and speculation was misleading or incomplete at the very least.
 
morrisond
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 6:05 pm

Here is the full press release:

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.
 
BEG2IAH
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 6:26 pm

morrisond wrote:
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.


Can Boeing reuse that static frame for a repeated test? Do they even need to repeat the test if they realize it was just a latch that failed?
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Revelation
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 6:41 pm

BEG2IAH wrote:
morrisond wrote:
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.

Can Boeing reuse that static frame for a repeated test? Do they even need to repeat the test if they realize it was just a latch that failed?

I think it's safe to say none of us can know the answer to those questions based on what is publicly shared.

This thread describes how the fix for the A380 wing ultimate load test failure was certified by analysis not a re-test.

It seems that option may be open to Boeing as well, if the static test frame is too damaged to reuse.

I would presume Boeing's statement about this not being thought to be a major schedule or design impact suggests they have a good handle on a timely solution.
Last edited by Revelation on Wed Sep 11, 2019 6:44 pm, edited 1 time in total.
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 6:42 pm

BEG2IAH wrote:
Do they even need to repeat the test if they realize it was just a latch that failed?

Not if they can use calculations/computer modeling to show that it will pass with the fix.
 
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 7:20 pm

Revelation wrote:
This thread describes how the fix for the A380 wing ultimate load test failure was certified by analysis not a re-test.

It seems that option may be open to Boeing as well, if the static test frame is too damaged to reuse.

I would presume Boeing's statement about this not being thought to be a major schedule or design impact suggests they have a good handle on a timely solution.


I'll be curious to know how exactly Airbus passed the A380 wing test by analysis. I can think of two ways. 1. They end up beefing up the structure with the data they already have to the point that it can be guaranteed to pass a hypothetical re-test. 2. Simply lower the final loads. Can it be something else entirely?
 
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 7:22 pm

Polot wrote:
BEG2IAH wrote:
Do they even need to repeat the test if they realize it was just a latch that failed?

Not if they can use calculations/computer modeling to show that it will pass with the fix.


YES --
If you can show that the failure was within error margins of the target simulation.
If things break far below or above your simulation software isn't worth its money.
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 7:26 pm

Erebus wrote:
I'll be curious to know how exactly Airbus passed the A380 wing test by analysis. I can think of two ways. 1. They end up beefing up the structure with the data they already have to the point that it can be guaranteed to pass a hypothetical re-test. 2. Simply lower the final loads. Can it be something else entirely?


IIRC, the final fix to ensure the A380 wing could reach the 150% ultimate load limit was the addition of 2.5Kg of extra material and fasteners per wing.
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 7:38 pm

scbriml wrote:
Erebus wrote:
I'll be curious to know how exactly Airbus passed the A380 wing test by analysis. I can think of two ways. 1. They end up beefing up the structure with the data they already have to the point that it can be guaranteed to pass a hypothetical re-test. 2. Simply lower the final loads. Can it be something else entirely?


IIRC, the final fix to ensure the A380 wing could reach the 150% ultimate load limit was the addition of 2.5Kg of extra material and fasteners per wing.


Ah, straight to the point. Thanks for that answer. So, I'm right with my point # 1 then.

I suppose Boeing could analyse the exact point of failure in the cargo door and strengthen those areas, but the question now is if they could pass the wing structure at 150% load without a re-test, not knowing if and where it could fail.
 
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 7:40 pm

Erebus wrote:
I'll be curious to know how exactly Airbus passed the A380 wing test by analysis. I can think of two ways. 1. They end up beefing up the structure with the data they already have to the point that it can be guaranteed to pass a hypothetical re-test. 2. Simply lower the final loads. Can it be something else entirely?


Lowering the final loads would not meet the Certification Standard so the "fix" would be to analyze why it failed and then calculate the changes necessary to prevent the failure and then implement those changes in the physical units. This will most-likely involve beefing up the structure (as scbriml noted was done to make the A380 wing Certification Compliant).
 
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 8:53 pm

frigatebird wrote:
justloveplanes wrote:
SEPilot wrote:
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?

This could be a possibility. Ferpe wrote about it back in 2015: https://leehamnews.com/2015/04/02/bjorn ... derations/
He also mentions the 6,000 to 8000 ft cabin altitude pressure differences between the previous generation 777s and the 777X.

But does the 777X actually have an AL-LI fuselage? At the time of the article it was not yet decided.

An Alcoa press release from January 2016 doesn't address it directly, but I think you can infer from the following text that the fuselage isn't Al-Li:

    Under the new agreement, Alcoa Forgings and Extrusions will supply differentiated components for Boeing’s airplanes, including the wing, fuselage, and landing gear. These include:

    • Advanced titanium landing gear parts and complex titanium nacelle fittings for the 737 MAX, made using specialized presses gained through the Firth Rixson acquisition;
    • Boeing’s first-ever aluminum-lithium extrusion produced at Alcoa’s Lafayette facility for the 777X cargo floor, helping save weight and improve corrosion resistance; and
    • Large, near net shaped parts that improve the efficiency and help reduce the costs of Boeing’s in-house machining.

https://www.arconic.com/global/en/news/news_detail.asp?pageID=20160128000319en&newsYear=2016
 
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 10:52 pm

Noshow wrote:
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.
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 10:55 pm

Rumor mill once again is saying 777x flight test 1 will fly before the end of the year.

Rumor mill also saying first 2 engines will be back in Everett next month
 
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Re: Boeing 777X Testing Thread - 2019

Wed Sep 11, 2019 11:27 pm

Spetsnaz55 wrote:
Rumor mill once again is saying 777x flight test 1 will fly before the end of the year.

Rumor mill also saying first 2 engines will be back in Everett next month


I'd say that is unreliable. My understanding is GE still has not finalized the new coatings on the internal components that are showing premature wear.
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 3:39 am

Note that a composite wing will react differently than a metal wing at ultimate load. So Boeing can not do what Airbus did with he A380. Recall that the A380 experienced a failure. The metal went beyond yield and broke.

With the 777x wing, there is really no yield point and until you hear fiber break and delaminate, you can bring those wing up the same load path again.

At least if the failure is in the fuselage, they can take the same approach as the A380 and beef up the door structure to continue the test and fix it later. The most important thing is making sure the wing is good to Ultimate.

bt
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Opus99
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 10:29 am

Spetsnaz55 wrote:
Rumor mill once again is saying 777x flight test 1 will fly before the end of the year.

Rumor mill also saying first 2 engines will be back in Everett next month

That’s a very optimistic rumour. As much as I’d like it to be true. I really don’t see how
 
morrisond
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 10:58 am

bikerthai wrote:
Note that a composite wing will react differently than a metal wing at ultimate load. So Boeing can not do what Airbus did with he A380. Recall that the A380 experienced a failure. The metal went beyond yield and broke.

With the 777x wing, there is really no yield point and until you hear fiber break and delaminate, you can bring those wing up the same load path again.

At least if the failure is in the fuselage, they can take the same approach as the A380 and beef up the door structure to continue the test and fix it later. The most important thing is making sure the wing is good to Ultimate.

bt


Wasn't the A380 fix still not sufficient as didn't they have Wing Rib cracking issues in service as well? If the Wing Ribs had cracked in the test would that have meant a failed test?

Was the testing methodology not sufficient enough to catch the Wing Rib failures?

Should they have retested the A380 fix to make sure there were no other issues (wing rib cracking) at Ultimate load?
 
WIederling
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 11:43 am

bikerthai wrote:
Note that a composite wing will react differently than a metal wing at ultimate load. So Boeing can not do what Airbus did with he A380. Recall that the A380 experienced a failure. The metal went beyond yield and broke.

With the 777x wing, there is really no yield point and until you hear fiber break and delaminate, you can bring those wing up the same load path again.

At least if the failure is in the fuselage, they can take the same approach as the A380 and beef up the door structure to continue the test and fix it later. The most important thing is making sure the wing is good to Ultimate.

bt


You can't use a failed specimen a second time ( fixed up or not) . independent of the material composition.

The A380 wing test failed just below design targets. i.e. the simulation model was "good enough" but had a directed error.
Certification requirements were met adjusting the simulation to get rid of that directed error
and then adding material in the right places and rerun the simulation. success? -> method accepted and certification granted.

This could not have worked for the 787 wing test where damage started to develop
long before any sufficient force to create predicted damage was applied.
Additionally defects shew up in "unpredicted" places.
The simulation was fully unfit for the task.
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WIederling
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 11:53 am

morrisond wrote:
bikerthai wrote:
Note that a composite wing will react differently than a metal wing at ultimate load. So Boeing can not do what Airbus did with he A380. Recall that the A380 experienced a failure. The metal went beyond yield and broke.

With the 777x wing, there is really no yield point and until you hear fiber break and delaminate, you can bring those wing up the same load path again.

At least if the failure is in the fuselage, they can take the same approach as the A380 and beef up the door structure to continue the test and fix it later. The most important thing is making sure the wing is good to Ultimate.

bt


Wasn't the A380 fix still not sufficient as didn't they have Wing Rib cracking issues in service as well? If the Wing Ribs had cracked in the test would that have meant a failed test?

Was the testing methodology not sufficient enough to catch the Wing Rib failures?

Should they have retested the A380 fix to make sure there were no other issues (wing rib cracking) at Ultimate load?


wing rib cracking was more of a manufacturing plus different materials mated issue susceptible to fatigue.
Ultimate load test is independent of fatigue effects.

wing rib cracking probably would not have been exposed via the fatigue test frame work either
as it was "pushed" by temp cycles. ( cfrp webbing plate connected into an Al framing part )
QF32 produced early exposure. My understanding is that timed airframe checks would have
still been early enough to not be dangerous.
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StTim
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 11:54 am

I think the crackeed wing ribs were not related to the final load test issue. The testing that should have picked it up was the fatigue testing - not the ultimate strength testing.
 
WIederling
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 12:04 pm

StTim wrote:
I think the crackeed wing ribs were not related to the final load test issue. The testing that should have picked it up was the fatigue testing - not the ultimate strength testing.


Yup. my understanding too.
But the fatigue test would not have exposed it either
as it does not do temp cycles that were at the core of CFRP mated to AL.
Murphy is an optimist
 
StTim
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 12:06 pm

WIederling wrote:
StTim wrote:
I think the crackeed wing ribs were not related to the final load test issue. The testing that should have picked it up was the fatigue testing - not the ultimate strength testing.


Yup. my understanding too.
But the fatigue test would not have exposed it either
as it does not do temp cycles that were at the core of CFRP mated to AL.


True.
It became a new design learning,
 
Noshow
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 12:10 pm

It was early fatigue temperature related to different material used in the ribs.
All ribs became later converted to the same material. Early software could not predict the different material's temperature behavior precise enough.
 
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SomebodyInTLS
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 12:33 pm

morrisond wrote:
Wasn't the A380 fix still not sufficient as didn't they have Wing Rib cracking issues in service as well? If the Wing Ribs had cracked in the test would that have meant a failed test?


Completely different thing. Rib cracking had nothing to do with wing bending loads and was metal fatigue not static strength failure.

Was the testing methodology not sufficient enough to catch the Wing Rib failures?


The fatigue test (not the static test) should catch this and... it did. The fix was based on these test results.

Should they have retested the A380 fix to make sure there were no other issues (wing rib cracking) at Ultimate load?


Again, completely different thing. To make an analogy: take a stepladder, lay it flat across two supports so you can stand on it to paint the ceiling (supported by the main beams, not the steps). There's your wing bending.
Now imagine the steps would sometimes shake loose after a couple of years use, so you change the bolts joining them to the main beams. What effect does that have on you standing on it to paint the ceiling? Pretty much nothing.
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 12:43 pm

GE's use of the term "durability" is so misleading.

The early flight test is about verifying aerodynamics, no one cares about engine durability, unless the durability is so bad one can't count on the engines making it through one flight.

glideslope wrote:
My understanding is GE still has not finalized the new coatings on the internal components that are showing premature wear.

Could we see a scenario where GE uses a coating with more margins just to get one or two airplanes flying, then introduce the intended final coating later in the test program?
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Re: Boeing 777X Testing Thread - 2019

Thu Sep 12, 2019 1:23 pm

Noshow wrote:
Early software could not predict the different material's temperature behavior precise enough.


The thermal expansion differences between aluminum and graphite composite is well known. It is one of the first thing you have to deal with when designing the aluminum cure tool for a graphite composite panel. How it relates to fatigue cycles may not have been predicted precisely, but it could also reflect the difference design philosophy between Airbus and Boeing.

Airbus was more willing to use aluminum/graphite interface relying on extensive corrosion protection schemes. Boeing was less so, they ended up having to do so but I think limit the location to dry areas. Ultimately I believe Boeing went to Graphite and Titanium/Graphite interface and limit the use of the Aluminum/Graphite interfaces, specially where they anticipate moisture collection/condensation.

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Re: Boeing 777X Testing Thread - 2019

Fri Sep 13, 2019 2:41 am

Revelation wrote:
GE's use of the term "durability" is so misleading.

The early flight test is about verifying aerodynamics, no one cares about engine durability, unless the durability is so bad one can't count on the engines making it through one flight.

glideslope wrote:
My understanding is GE still has not finalized the new coatings on the internal components that are showing premature wear.

Could we see a scenario where GE uses a coating with more margins just to get one or two airplanes flying, then introduce the intended final coating later in the test program?


I’m really not in a position to expand on my previous comment.
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Opus99
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 16, 2019 3:03 pm

Hearing again that GE is preparing to ship repaired engines back to Boeing in October
 
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SEPilot
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 16, 2019 3:20 pm

morrisond wrote:
bikerthai wrote:
Note that a composite wing will react differently than a metal wing at ultimate load. So Boeing can not do what Airbus did with he A380. Recall that the A380 experienced a failure. The metal went beyond yield and broke.

With the 777x wing, there is really no yield point and until you hear fiber break and delaminate, you can bring those wing up the same load path again.

At least if the failure is in the fuselage, they can take the same approach as the A380 and beef up the door structure to continue the test and fix it later. The most important thing is making sure the wing is good to Ultimate.

bt


Wasn't the A380 fix still not sufficient as didn't they have Wing Rib cracking issues in service as well? If the Wing Ribs had cracked in the test would that have meant a failed test?

Was the testing methodology not sufficient enough to catch the Wing Rib failures?

Should they have retested the A380 fix to make sure there were no other issues (wing rib cracking) at Ultimate load?

Cracking and failure are not necessarily from the same cause. Cracking, especially in aluminum, can come from repeated flexing at loads well below failure. This would show up in fatigue tests but not in the ultimate load test.
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Re: Boeing 777X Testing Thread - 2019

Mon Sep 16, 2019 4:00 pm

in TWITTER:
GOOD NEWS GE Aviation is getting ready to start shipping repaired GE9X Engine to Boeing Everett Factory between September 28 to October 27, 2019
 
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ikolkyo
Posts: 2648
Joined: Tue Nov 05, 2013 8:43 pm

Re: Boeing 777X Testing Thread - 2019

Mon Sep 16, 2019 4:29 pm

Great news, the aircraft will likely fly this year after all.
 
OmerMaz
Posts: 40
Joined: Mon Aug 05, 2019 8:38 am

Re: Boeing 777X Testing Thread - 2019

Mon Sep 16, 2019 5:12 pm

Who knows, at this rate, it will be nice if it might actualy fly on New Year's eve, or even by that time, allowing for a cerftification by the end of 2020.
But those are all just speculations, we just have to wait for her first take off.
 
9Patch
Posts: 333
Joined: Wed Mar 13, 2019 10:38 pm

Re: Boeing 777X Testing Thread - 2019

Mon Sep 16, 2019 5:16 pm

pabloeing wrote:
in TWITTER:
GOOD NEWS GE Aviation is getting ready to start shipping repaired GE9X Engine to Boeing Everett Factory between September 28 to October 27, 2019

Who Tweeted this?
 
nycbjr
Posts: 185
Joined: Wed Aug 22, 2007 6:45 am

Re: Boeing 777X Testing Thread - 2019

Mon Sep 16, 2019 5:39 pm

9Patch wrote:
pabloeing wrote:
in TWITTER:
GOOD NEWS GE Aviation is getting ready to start shipping repaired GE9X Engine to Boeing Everett Factory between September 28 to October 27, 2019

Who Tweeted this?


This is what I found on twitter.. so not an official source..

https://twitter.com/b777xLovers/status/ ... 83744?s=20
 
Opus99
Posts: 39
Joined: Thu May 30, 2019 10:51 pm

Re: Boeing 777X Testing Thread - 2019

Mon Sep 16, 2019 5:56 pm

nycbjr wrote:
9Patch wrote:
pabloeing wrote:
in TWITTER:
GOOD NEWS GE Aviation is getting ready to start shipping repaired GE9X Engine to Boeing Everett Factory between September 28 to October 27, 2019

Who Tweeted this?


This is what I found on twitter.. so not an official source..

https://twitter.com/b777xLovers/status/ ... 83744?s=20

True, but previous news from that account always seems to be right before it goes mainstream
 
9Patch
Posts: 333
Joined: Wed Mar 13, 2019 10:38 pm

Re: Boeing 777X Testing Thread - 2019

Mon Sep 16, 2019 6:14 pm

nycbjr wrote:
9Patch wrote:
pabloeing wrote:
in TWITTER:
GOOD NEWS GE Aviation is getting ready to start shipping repaired GE9X Engine to Boeing Everett Factory between September 28 to October 27, 2019

Who Tweeted this?


This is what I found on twitter.. so not an official source..

https://twitter.com/b777xLovers/status/ ... 83744?s=20


I hope it's true, but I'll wait for an official announcement from GE or Boeing.
 
Spetsnaz55
Posts: 96
Joined: Wed Feb 20, 2019 2:38 am

Re: Boeing 777X Testing Thread - 2019

Mon Sep 16, 2019 7:14 pm

Told ya!!! Ita gonna happen. 777x will fly before year end
 
justloveplanes
Posts: 996
Joined: Thu Jul 08, 2004 5:38 am

Re: Boeing 777X Testing Thread - 2019

Thu Sep 19, 2019 12:15 pm

As discussed earlier in this thread, Boeing did announce the aft depressurization occurred at 99% of the final test load (@148.5%).
 
User avatar
kanban
Posts: 3948
Joined: Sun Jan 06, 2008 1:00 am

Re: Boeing 777X Testing Thread - 2019

Thu Sep 19, 2019 3:46 pm

Part of the testing involves cycling the fuselage pressure up and down hundreds of times looking for stress/fatigue issues. doing the highest pressure test first destroys all that information. like bending the wings to failure on the first test..... now you need to build another set of wings and install them, however you would have a bastard airframe and anything found on subsequent cycle testing would always be in doubt as to whether it was a basic frame issue or a repair frame issue.

there may be no design failure here, but a manufacturing plan or sequence issue, say something simple like a failure to de-burr the lock attach holes.

Anyway this will all be resolved before the repaired engines arrive.
 
justloveplanes
Posts: 996
Joined: Thu Jul 08, 2004 5:38 am

Re: Boeing 777X Testing Thread - 2019

Thu Sep 19, 2019 4:40 pm

nycbjr wrote:
9Patch wrote:
pabloeing wrote:
in TWITTER:
GOOD NEWS GE Aviation is getting ready to start shipping repaired GE9X Engine to Boeing Everett Factory between September 28 to October 27, 2019

Who Tweeted this?


This is what I found on twitter.. so not an official source..

https://twitter.com/b777xLovers/status/ ... 83744?s=20


Still looking for an official announcement?

I would be interested if GE reran their max stress test, and if so did the max thrust change?
 
User avatar
Stitch
Posts: 26346
Joined: Wed Jul 06, 2005 4:26 am

Re: Boeing 777X Testing Thread - 2019

Thu Sep 19, 2019 7:55 pm

justloveplanes wrote:
I would be interested if GE reran their max stress test, and if so did the max thrust change?


There would be no reason to since no in-service engine would ever operate anywhere near those levels so its effect on reliability is irrelevant.
 
justloveplanes
Posts: 996
Joined: Thu Jul 08, 2004 5:38 am

Re: Boeing 777X Testing Thread - 2019

Thu Sep 19, 2019 8:04 pm

Stitch wrote:
justloveplanes wrote:
I would be interested if GE reran their max stress test, and if so did the max thrust change?


There would be no reason to since no in-service engine would ever operate anywhere near those levels so its effect on reliability is irrelevant.


Hmmm, so why run the extreme test in the first place? If is to gain knowledge and get a certainty level about the reliability of the engine, then a stress test is good.

Question still remains, how do you validate the fix? Rerunning the test or analytical? If max stress is a certification requirement, then you would need at least an analysis.
 
User avatar
Stitch
Posts: 26346
Joined: Wed Jul 06, 2005 4:26 am

Re: Boeing 777X Testing Thread - 2019

Thu Sep 19, 2019 8:48 pm

justloveplanes wrote:
Hmmm, so why run the extreme test in the first place?


Because it is part of the certification process - same reason they bend the wings to 150% of what they could ever possibly see in service. Modern modeling is likely accurate enough to do away with the 150% "cushion", but aviation is still a conservative discipline. :biggrin:


justloveplanes wrote:
If is to gain knowledge and get a certainty level about the reliability of the engine, then a stress test is good.


As I recall from the thread, the engine was only run at this level for around three hours.


justloveplanes wrote:
Question still remains, how do you validate the fix?


I would expect GE would continue to run their test-bed engine on the 747 / in the lab as well as closely monitoring the 777-9 test fleet as it gains hours.

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