"Tech Deep Dive" Boeing 787 fuselage shimming issues
Thread Starter
"Tech Deep Dive" Boeing 787 fuselage shimming issues
I jump start this thread with some info that WillowRun, Commander Taco and I collected in the Boeing News thread
Maybe some members with knowledge help to do an amateur/preliminary assessment or "Deep Dive" of the recent Whistleblower versus the Boeing statements. So Rumour Section seems to be appropriate?
I put the sources in separate posts.
Maybe some members with knowledge help to do an amateur/preliminary assessment or "Deep Dive" of the recent Whistleblower versus the Boeing statements. So Rumour Section seems to be appropriate?
I put the sources in separate posts.
Thread Starter
Source: Shims: The thin end of Boeing’s wedge (key.aero)
(June 2021, digged out by waito, bold is my marking of highlights)
==============
"In August of 2019, we determined that there was an issue with shimming in a specific batch of aircraft that was produced in early 2019," a Boeing spokesperson told Airliner World.
That warrants some explanation. The problem was found in the joints between two aft fuselage tubes: section 47, which includes the rear pressure bulkhead, and the unpressurised section 48, which accommodates the horizontal tailplane. Like the rest of the fuselage, these are made from carbon fibre-reinforced plastics. While produced to strict specifications, carbon fibre is a rigid material where even a slight imperfection can cause tiny gaps when parts are mated together. Shims fill these gaps.
It turned out that a batch of shims produced in early 2019 were of an incorrect size, with Boeing’s spokesperson adding: “The initial problem that was identified in August 2019 was down to a software issue related to the size of shims… An electric ‘eye’ failed to identify incorrectly sized shims. After we discovered the issue, it was addressed in the production system.” However, the US aerospace giant was quick to state “that issue, in itself, was not an immediate safety of flight issue.”
The fault isn’t new to the Dreamliner. A March 2014 critical systems review of the 787-8 prompted by its notorious battery issues described shimming problems on sections 46, 47, 48 and the horizontal stabiliser. Boeing has stressed that this fault has been addressed and that it is unrelated to the latest problems. This also applies to a quality issue on the horizontal tailplane and vertical fin, where slight deformation was discovered after too much pressure had been placed on specific areas during production.
The bad batch
Fast-forward to August 2020 and further production irregularities showed up on fuselage sections 47 and 48. This time, the skin flatness of the inner mould line – the inside of the barrels close to the joints – was incorrect. The US aerospace giant’s spokesperson explained: “There are very tight tolerances for the flatness of the fuselage skin inner mould line. Anything greater than five one-thousandths (0.005) of an inch is outside of the engineering tolerance. This is comparable to the width of a human hair or a piece of paper. Related to the skin flatness, we found that there were some non-conformances and that, on some aircraft, skin flatness was found to be beyond engineering tolerances.
“When that was identified, we also looked across our production system to understand if there would be other impacts to safety or quality. We went back to look at the earlier batch of airplanes produced in 2019 and identified eight airplanes that had both of these issues. Based on that determination, we recommended that those eight be put out of service.
“While neither the shimming nor the skin flatness problem is a safety of flight issue on its own, the combination of the two factors in the same location in the aft body was why we recommended the removal of those eight airplanes from service until the repair.”
=============================
I summarize:
March 2014: [EDIT] A Critical Systems Review by FAA and Boeingpublished their final report, including "shimming issues sect 46-48 + Horizontal stab" & "Deformation in HS/Vertical Fin Area" due to over pressure on some parts
August 2019: shims with incorrect size
August 2020: The surface tolerance issue exceeding 0.005" in section 47-48
October 2020-March 2021: Deliveries to customers stopped
(June 2021, digged out by waito, bold is my marking of highlights)
==============
"In August of 2019, we determined that there was an issue with shimming in a specific batch of aircraft that was produced in early 2019," a Boeing spokesperson told Airliner World.
That warrants some explanation. The problem was found in the joints between two aft fuselage tubes: section 47, which includes the rear pressure bulkhead, and the unpressurised section 48, which accommodates the horizontal tailplane. Like the rest of the fuselage, these are made from carbon fibre-reinforced plastics. While produced to strict specifications, carbon fibre is a rigid material where even a slight imperfection can cause tiny gaps when parts are mated together. Shims fill these gaps.
It turned out that a batch of shims produced in early 2019 were of an incorrect size, with Boeing’s spokesperson adding: “The initial problem that was identified in August 2019 was down to a software issue related to the size of shims… An electric ‘eye’ failed to identify incorrectly sized shims. After we discovered the issue, it was addressed in the production system.” However, the US aerospace giant was quick to state “that issue, in itself, was not an immediate safety of flight issue.”
The fault isn’t new to the Dreamliner. A March 2014 critical systems review of the 787-8 prompted by its notorious battery issues described shimming problems on sections 46, 47, 48 and the horizontal stabiliser. Boeing has stressed that this fault has been addressed and that it is unrelated to the latest problems. This also applies to a quality issue on the horizontal tailplane and vertical fin, where slight deformation was discovered after too much pressure had been placed on specific areas during production.
The bad batch
Fast-forward to August 2020 and further production irregularities showed up on fuselage sections 47 and 48. This time, the skin flatness of the inner mould line – the inside of the barrels close to the joints – was incorrect. The US aerospace giant’s spokesperson explained: “There are very tight tolerances for the flatness of the fuselage skin inner mould line. Anything greater than five one-thousandths (0.005) of an inch is outside of the engineering tolerance. This is comparable to the width of a human hair or a piece of paper. Related to the skin flatness, we found that there were some non-conformances and that, on some aircraft, skin flatness was found to be beyond engineering tolerances.
“When that was identified, we also looked across our production system to understand if there would be other impacts to safety or quality. We went back to look at the earlier batch of airplanes produced in 2019 and identified eight airplanes that had both of these issues. Based on that determination, we recommended that those eight be put out of service.
“While neither the shimming nor the skin flatness problem is a safety of flight issue on its own, the combination of the two factors in the same location in the aft body was why we recommended the removal of those eight airplanes from service until the repair.”
=============================
I summarize:
March 2014: [EDIT] A Critical Systems Review by FAA and Boeingpublished their final report, including "shimming issues sect 46-48 + Horizontal stab" & "Deformation in HS/Vertical Fin Area" due to over pressure on some parts
August 2019: shims with incorrect size
August 2020: The surface tolerance issue exceeding 0.005" in section 47-48
October 2020-March 2021: Deliveries to customers stopped
Last edited by waito; 29th Apr 2024 at 20:27.
Thread Starter
From WillowRun's summary of
Aviation Week dated April 22-May 5, 2024(?)
(I don't know a link, probably behind paywall: Bold again is my markup)
========================
(Remark from WillowRun: The person quoted is the vp and chief engineer etc ....) :
In-service reviews of the oldest and most used airframes underpin results from tests done early in the program to validate the 787’s design—tests that unknowingly trialed production flaws discovered years later.
“The most impactful data is the data that we got from our full-scale fatigue test,” Chisholm said. “The build condition [was] the same as what we saw in the later build.”
Put another way, the same nonconformances that crept into the first 980 aircraft were present in the fatigue test article. While the revelation does not reflect well on Boeing’s original quality assurance process, it bolsters the argument that its design—including material selection and tolerances—is robust.
“In over 165,000 cycles, there were zero fatigue issues in the composite structure,” Chisholm said.
The tests, which began in September 2010 on ZY998, the third 787 airframe built, ran through 2015 and simulated entire flights, from taxi through ascent, cruise, descent and back to taxi (AW&ST Dec. 21, 2015-Jan. 3, 2016, p. 51). Targeted at creating a dataset for the airframe’s durability, the tests subjected the structure to loads that simulated more than 3.6 times the design life of 44,000 flight cycles.
Testing was conducted in a steel rig weighing more than 1 million lb. at the Boeing manufacturing plant in Everett, Washington. The rig included more than 100 mechanical connections to push, pull and twist the 182-ft.-long fuselage, wing forward leading edge and vertical stabilizer. The 787 structure incorporated over 3,000 sensors that evaluated more than 40 million discrete load conditions as the airframe was subjected to shear forces, bending moments and torsion loads typically experienced during five flight conditions ranging from benign to extremely turbulent.
Although some parts failed over the course of testing, they were all metallic. Components and parts that cracked or failed prematurely included a metal bearing pad in the main landing-gear support structure and tie-rod end lug and support fittings. There were no catastrophic failures during the test, Boeing adds.
The fatigue-test airframe incorporated additional sensors along the side-of-body wingbox joint, which was reinforced after earlier static tests revealed weakness in the area. The redesign, which pushed back first flight of the 787 to December 2009, was validated in static tests the previous month and later incorporated into ZY998. Compared with fatigue tests on earlier metallic airframes, the 787 test unit included more sensors on various stiffener terminations and more extensive periodic inspections than required by the baseline maintenance program.
Average 787 utilization is about 600 cycles per year, Boeing said. The busiest aircraft operate 900-1,400 cycles annually, Aviation Week Network Fleet Discovery data show. The highest-time 787, an All Nippon Airways 787-8, has flown 16,500 cycles in its 11-year service life.
The 44,000-cycle life expectancy is reflected in the extent of the 787 tests compared with previous fatigue tests on conventional aluminum-built airframes, such as the 777, which completed the then-record number of 120,000 simulated cycles in 1997. This represented the equivalent of 60 years in operation or twice the 777’s design service objective (DSO) of 60,000 flights. The DSOs of the 787 and 777 have both been significantly extended beyond previous generations, such as the 757 and 767, which underwent fatigue tests simulating 100,000 flights, or twice a 20-year DSO of 50,000 flights.
Aviation Week dated April 22-May 5, 2024(?)
(I don't know a link, probably behind paywall: Bold again is my markup)
========================
(Remark from WillowRun: The person quoted is the vp and chief engineer etc ....) :
In-service reviews of the oldest and most used airframes underpin results from tests done early in the program to validate the 787’s design—tests that unknowingly trialed production flaws discovered years later.
“The most impactful data is the data that we got from our full-scale fatigue test,” Chisholm said. “The build condition [was] the same as what we saw in the later build.”
Put another way, the same nonconformances that crept into the first 980 aircraft were present in the fatigue test article. While the revelation does not reflect well on Boeing’s original quality assurance process, it bolsters the argument that its design—including material selection and tolerances—is robust.
“In over 165,000 cycles, there were zero fatigue issues in the composite structure,” Chisholm said.
The tests, which began in September 2010 on ZY998, the third 787 airframe built, ran through 2015 and simulated entire flights, from taxi through ascent, cruise, descent and back to taxi (AW&ST Dec. 21, 2015-Jan. 3, 2016, p. 51). Targeted at creating a dataset for the airframe’s durability, the tests subjected the structure to loads that simulated more than 3.6 times the design life of 44,000 flight cycles.
Testing was conducted in a steel rig weighing more than 1 million lb. at the Boeing manufacturing plant in Everett, Washington. The rig included more than 100 mechanical connections to push, pull and twist the 182-ft.-long fuselage, wing forward leading edge and vertical stabilizer. The 787 structure incorporated over 3,000 sensors that evaluated more than 40 million discrete load conditions as the airframe was subjected to shear forces, bending moments and torsion loads typically experienced during five flight conditions ranging from benign to extremely turbulent.
Although some parts failed over the course of testing, they were all metallic. Components and parts that cracked or failed prematurely included a metal bearing pad in the main landing-gear support structure and tie-rod end lug and support fittings. There were no catastrophic failures during the test, Boeing adds.
The fatigue-test airframe incorporated additional sensors along the side-of-body wingbox joint, which was reinforced after earlier static tests revealed weakness in the area. The redesign, which pushed back first flight of the 787 to December 2009, was validated in static tests the previous month and later incorporated into ZY998. Compared with fatigue tests on earlier metallic airframes, the 787 test unit included more sensors on various stiffener terminations and more extensive periodic inspections than required by the baseline maintenance program.
Average 787 utilization is about 600 cycles per year, Boeing said. The busiest aircraft operate 900-1,400 cycles annually, Aviation Week Network Fleet Discovery data show. The highest-time 787, an All Nippon Airways 787-8, has flown 16,500 cycles in its 11-year service life.
The 44,000-cycle life expectancy is reflected in the extent of the 787 tests compared with previous fatigue tests on conventional aluminum-built airframes, such as the 777, which completed the then-record number of 120,000 simulated cycles in 1997. This represented the equivalent of 60 years in operation or twice the 777’s design service objective (DSO) of 60,000 flights. The DSOs of the 787 and 777 have both been significantly extended beyond previous generations, such as the 757 and 767, which underwent fatigue tests simulating 100,000 flights, or twice a 20-year DSO of 50,000 flights.
Thread Starter
Aviation Week “Check 6” podcast of April 19, 2024
Podcast: Boeing Over A Barrel | Aviation Week Network
3 Journalists with expertise in Aviation
Its Transcript is quite long, so here my imperfect selection of quotes. The linked Transcript is worth the read, but again note these seem to be "only" Aviation specialised Journalists
====================
… manufacturing problems that are known now on the 787 and caused production to slow to a crawl in the 2021/'22 time period, and caused deliveries to stop for the better part of two years really, those manufacturing issues are being... The fixes that Boeing was supposed to put in place are being short-cutted and the assembly processes are still introducing risk on the production line.
Boeing has acknowledged that not only did the 787 assembly process have issues, but basically, every 787 out there was not built to their design specs. They didn't conform and getting them into conformance is they were able to get the FAA to sign off on their plan to begin deliveries again or restart deliveries in (what was it?) August of 2022.
…
The issues are, in the simplest terms possible, mainly gaps between pieces of structure in mostly fuselage barrels, but there are some other parts as well (door surrounds and things like that) where there were gaps. Tolerances are exceeded in the assembly process. There are a couple of ways that those gaps are normal in every aircraft assembly process and they are failed using shims usually. In Boeing's case, sometimes shims were not used when they should have been sometimes incorrect shims were used.
Salehpour (waito: The whistleblower I abbreviated as Sam S.) also said that the process that Boeing uses to get pieces to fit together, a step known as fit-up force, basically means you're using force to get the fit between two large pieces of structure as tight as possible and minimize that gap. Boeing was using force that was outside of its own declared engineering specifications and, therefore, introducing potential strain into pieces before they were being fastened together. That's still with some gaps left in there potentially.
=======================
Later in the transcript, a very detailed explanation of stresses, joints and composite behaviour. I should not copy all of that, please read it as a whole! Here are some snippets to hint what they discussed:
Now, I'll get to why composites are challenges, …
So let's go and look at why composites and metals are different…
Composites wants the loads to go in in the direction…
Now with composites, the biggest thing with …
Secondly, it's very stiff, so you can't bend it…
These are bolted joints, …
You size the shim to fill that gap….
And as Sean again said, it's different with composites. In composites, it's about microcracking of the plastic resin. It's about pull-through and other types of failures around the fasteners. …
Podcast: Boeing Over A Barrel | Aviation Week Network
3 Journalists with expertise in Aviation
Its Transcript is quite long, so here my imperfect selection of quotes. The linked Transcript is worth the read, but again note these seem to be "only" Aviation specialised Journalists
====================
… manufacturing problems that are known now on the 787 and caused production to slow to a crawl in the 2021/'22 time period, and caused deliveries to stop for the better part of two years really, those manufacturing issues are being... The fixes that Boeing was supposed to put in place are being short-cutted and the assembly processes are still introducing risk on the production line.
Boeing has acknowledged that not only did the 787 assembly process have issues, but basically, every 787 out there was not built to their design specs. They didn't conform and getting them into conformance is they were able to get the FAA to sign off on their plan to begin deliveries again or restart deliveries in (what was it?) August of 2022.
…
The issues are, in the simplest terms possible, mainly gaps between pieces of structure in mostly fuselage barrels, but there are some other parts as well (door surrounds and things like that) where there were gaps. Tolerances are exceeded in the assembly process. There are a couple of ways that those gaps are normal in every aircraft assembly process and they are failed using shims usually. In Boeing's case, sometimes shims were not used when they should have been sometimes incorrect shims were used.
Salehpour (waito: The whistleblower I abbreviated as Sam S.) also said that the process that Boeing uses to get pieces to fit together, a step known as fit-up force, basically means you're using force to get the fit between two large pieces of structure as tight as possible and minimize that gap. Boeing was using force that was outside of its own declared engineering specifications and, therefore, introducing potential strain into pieces before they were being fastened together. That's still with some gaps left in there potentially.
=======================
Later in the transcript, a very detailed explanation of stresses, joints and composite behaviour. I should not copy all of that, please read it as a whole! Here are some snippets to hint what they discussed:
Now, I'll get to why composites are challenges, …
So let's go and look at why composites and metals are different…
Composites wants the loads to go in in the direction…
Now with composites, the biggest thing with …
Secondly, it's very stiff, so you can't bend it…
These are bolted joints, …
You size the shim to fill that gap….
And as Sean again said, it's different with composites. In composites, it's about microcracking of the plastic resin. It's about pull-through and other types of failures around the fasteners. …
Last edited by waito; 28th Apr 2024 at 09:17.
I seem to recall reporting that the shim problem started with an attempt by Boeing to computerize a process that had been done by humans. This resulted in Boeing being able to get rid of 220 production and QA people. Sadly like so many recent Boeing decisions the short term savings were overwhelmed by the resultant costs to clean up the inevitable mess.
Is this story correct or was it miss reported?
Is this story correct or was it miss reported?
Thread Starter
A hint was in the first article above:
and the shimming issues didn't start with it, nor did they end ...
was identified in August 2019 was down to a software issue related to the size of shims… An electric ‘eye’ failed to identify incorrectly sized shims.
Last edited by waito; 28th Apr 2024 at 16:43.
The problem, once again, isn't the cost saving change. Automation generally produces far more consistent and traceable results that are far cheaper. The CPU in the computer that is used to enter comments here wasn't hand-wired by exhaustively trained CPU builders.
The problem appears to be in a failed transition program that would have run the shims through whatever automated inspection and then have that inspection confirmed before moving the shims to production. Perhaps they did run a transition program, but for not long enough to catch edge cases or something changed when the equipment was moved from off-line to on-line with production.
The result is 219 fewer sources of random error, and one new source of procedural error. It is far easier to change automation to fix a procedural error. Unfortunately for an automation procedural error, it can make a lot of mistakes, but a correctly designed system will also make every step traceable. In automotive, they have sometimes had recalls down to a particular operation on a particular shift using an automated tool to install bolts; the tool was miscalibrated or malfunctioning, and there is traceability into exactly which cars were worked on during that period.
I can think of nothing more mind-numbing than an effort that requires 220 people measuring the thickness of shims.
The problem appears to be in a failed transition program that would have run the shims through whatever automated inspection and then have that inspection confirmed before moving the shims to production. Perhaps they did run a transition program, but for not long enough to catch edge cases or something changed when the equipment was moved from off-line to on-line with production.
The result is 219 fewer sources of random error, and one new source of procedural error. It is far easier to change automation to fix a procedural error. Unfortunately for an automation procedural error, it can make a lot of mistakes, but a correctly designed system will also make every step traceable. In automotive, they have sometimes had recalls down to a particular operation on a particular shift using an automated tool to install bolts; the tool was miscalibrated or malfunctioning, and there is traceability into exactly which cars were worked on during that period.
I can think of nothing more mind-numbing than an effort that requires 220 people measuring the thickness of shims.
Thread Starter
I'm struggling what - reading the info we collected here so far - was the shimming issue that Boeing said was covered by the Full Fatique test, and the author of the article linked with the first 980 produced 787s. The nature of the 2014 findings is unclear to me.
The findings in 2019 was the incorrect shimming size - was this a condition that could have happened before when workers checked the size?
The finding in 2020 was the out of tolerance of the skin flatness. I assume this was present all the time, but I can't pinpoint it.
Now, the fuselage in the testbed, did it have all 3 issues, or at least 2 issues combined? If not, the fatique test wouldn't cover the worst case.
I mean, they pulled 8 aircraft from service to address the combined issue of skin flatness + wrong sized shims. Checking planes from 2019 production on. What if the earlier aircraft, built before the magic eye check, also had this combination? The Fatique test was equipped with perfect sized shims I assume.
This could be the weakness that Whistleblower Sam S. is pointing to.
What's your assessment?
The findings in 2019 was the incorrect shimming size - was this a condition that could have happened before when workers checked the size?
The finding in 2020 was the out of tolerance of the skin flatness. I assume this was present all the time, but I can't pinpoint it.
Now, the fuselage in the testbed, did it have all 3 issues, or at least 2 issues combined? If not, the fatique test wouldn't cover the worst case.
I mean, they pulled 8 aircraft from service to address the combined issue of skin flatness + wrong sized shims. Checking planes from 2019 production on. What if the earlier aircraft, built before the magic eye check, also had this combination? The Fatique test was equipped with perfect sized shims I assume.
This could be the weakness that Whistleblower Sam S. is pointing to.
What's your assessment?
Without any documentation I have no way to know what validity there is to the whistleblower complaint. It's got to run thousands to tens of thousands of pages of inspection results, as-installed shims vs. ideal sized shims; what engineering studies may have done; what calculations may have been performed; what testing may have done. On second thought - hundreds of thousands of pages.
But I have every confidence that no one in Congress looking at this problem will do more than play to the crowd and the usual "demand answers."
But I have every confidence that no one in Congress looking at this problem will do more than play to the crowd and the usual "demand answers."
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Without any documentation I have no way to know what validity there is to the whistleblower complaint. It's got to run thousands to tens of thousands of pages of inspection results, as-installed shims vs. ideal sized shims; what engineering studies may have done; what calculations may have been performed; what testing may have done. On second thought - hundreds of thousands of pages.
But I have every confidence that no one in Congress looking at this problem will do more than play to the crowd and the usual "demand answers."
But I have every confidence that no one in Congress looking at this problem will do more than play to the crowd and the usual "demand answers."
Of course the ACSAA legislation doesn't solve long-term issues with FAA; funding, separating the Air Traffic Management function (if not creating an entity funded other than by Congressional machinations and whims) from Certification, among other things.
If I wished to pick a little bit of a fight with a well-known D.C. attorney and law firm - the legal eagles representing and (presumably) advising Mr Salehpour - I wouldn't do so from behind an internet forum's callsign anonymity setup. For now, it needs to be emphasized again, why are the documents that legal counsel included with their letter to FAA not being released to the public? (Inquiring minds ..... hat, coat)
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I haven't designed an internal reporting system that would prevent or materially mitigate the concerns articulated (MechEngr), although the notion of putting a short timeline in place for a reporting and review loop into Congress is (I think) a straw man. Beyond not denying the objections to it raised in the post, it can't be viewed seriously, because of the currently dysfunctional status of the United States Congress, especially the House. It wasn't always this bad but it is now.
If the recent legislation does nothing more than produce the report, and testimony, of the Expert Panel - I mean, those three individuals have pretty impressive backgrounds and qualifications, no? - then it was worth the effort.
I disagree about the confidentiality of a settlement through an NDA. That is a different matter entirely from the failure to release the documents provided to FAA. Neither Salehpour nor his legal counsel have the right to claim protection of Boeing's proprietary information on the company's behalf - if that's even what is in the documents. They have brought his claims to the public arena, and without full disclosure, the scrutiny is incomplete. And failure to release the documents provided to FAA by the law firm cannot be squared with the scope, or specific items, of the request for documents sent by the Senate Permanent Subcommittee on Investigations to Boeing. I have no knowledge, direct, personal, or otherwise, of the existence or absence of any category of documents requested in the letter. But I do read standard written English and it is quite difficult to describe anything Salehpour could have submitted to FAA not also within the scope and items of the Senate Subcommittee request. Perhaps Mr Salehpour has private notes; but Boeing would not have those, so not covered by the Subcommittee request.
I mean, I'm plenty cynical, particularly when it comes to Senatorial grandstanding. But to produce a hearing about what the American people have to know about safety of major aircraft programs but then not produce the full record currently in process within the interagency -- "hard disagree" as they say.
If the recent legislation does nothing more than produce the report, and testimony, of the Expert Panel - I mean, those three individuals have pretty impressive backgrounds and qualifications, no? - then it was worth the effort.
I disagree about the confidentiality of a settlement through an NDA. That is a different matter entirely from the failure to release the documents provided to FAA. Neither Salehpour nor his legal counsel have the right to claim protection of Boeing's proprietary information on the company's behalf - if that's even what is in the documents. They have brought his claims to the public arena, and without full disclosure, the scrutiny is incomplete. And failure to release the documents provided to FAA by the law firm cannot be squared with the scope, or specific items, of the request for documents sent by the Senate Permanent Subcommittee on Investigations to Boeing. I have no knowledge, direct, personal, or otherwise, of the existence or absence of any category of documents requested in the letter. But I do read standard written English and it is quite difficult to describe anything Salehpour could have submitted to FAA not also within the scope and items of the Senate Subcommittee request. Perhaps Mr Salehpour has private notes; but Boeing would not have those, so not covered by the Subcommittee request.
I mean, I'm plenty cynical, particularly when it comes to Senatorial grandstanding. But to produce a hearing about what the American people have to know about safety of major aircraft programs but then not produce the full record currently in process within the interagency -- "hard disagree" as they say.
Have there been any reported issues around those production joints with in service 787s?
I'm pretty sure I'm up to date with service bulletins but I can remember any.
I'm pretty sure I'm up to date with service bulletins but I can remember any.
Thread Starter
We went back to look at the earlier batch of airplanes produced in 2019 and identified eight airplanes that had both of these issues. Based on that determination, we recommended that those eight be put out of service.
Only this hint from the Boeing Spokesperson (see first article)
We went back to look at the earlier batch of airplanes produced in 2019 and identified eight airplanes that had both of these issues. Based on that determination, we recommended that those eight be put out of service.
We went back to look at the earlier batch of airplanes produced in 2019 and identified eight airplanes that had both of these issues. Based on that determination, we recommended that those eight be put out of service.
Thread Starter
Thread Starter
From https://theaircurrent.com/aviation-s...uctural-issue/
August 27th, 2020:
They are strict on copyright, so I refrain to quote all of it. It names some airlines affected, the rest is the same info we already collected.
-------------------
From 2012
https://www.reuters.com/article/idUSL2E8DNATN/
And the article mentions that they intended to save more than a Billion Dollars by streamlining the production
------------------- It's really easy to quickly find sources.
AD for 787-8 and - 9 ... shimming issues
https://www.federalregister.gov/docu...pany-airplanes
-------------------
That one took a while. I found the 2014 Final report of the Critical Systems Review by FAA and Boeing. So that one addressed earlier findings, the ones from 2012?
I haven't read the report beyond the exec summary. That listed the fuselage, shimming issues in both categories "Design" and "Manufacturing"
Boeing 787-8 Design, Certification, and Manufacturing Systems Review - March 19, 2014 (faa.gov) (PDF file)
August 27th, 2020:
Boeing earlier this week instructed airlines to pull a batch of eight recently-manufactured 787 Dreamliners...
-------------------
From 2012
https://www.reuters.com/article/idUSL2E8DNATN/
Boeing exec says 787 shim repair takes 10-14 days
Feb 23 (Reuters) - The repair needed to correct a flaw in the fuselage of Boeing Co's new 787 Dreamliner will take 10 to 14 days per plane, a top Boeing executive said on Thursday.Speaking at an event hosted by Barclays Capital, Pat Shanahan, general manager of airplane programs for Boeing Commercial Airplanes, said it is not a complex repair, but it takes valuable time as the company races to ramp up production for the long-awaited carbon-composite airplane.
(...)
Earlier this month, Boeing reported incorrect shimming and signs of "delamination" on a support structure in the rear fuselage. Delamination occurs when repeated stress causes laminated composite materials to begin to separate.
(...)
Feb 23 (Reuters) - The repair needed to correct a flaw in the fuselage of Boeing Co's new 787 Dreamliner will take 10 to 14 days per plane, a top Boeing executive said on Thursday.Speaking at an event hosted by Barclays Capital, Pat Shanahan, general manager of airplane programs for Boeing Commercial Airplanes, said it is not a complex repair, but it takes valuable time as the company races to ramp up production for the long-awaited carbon-composite airplane.
(...)
Earlier this month, Boeing reported incorrect shimming and signs of "delamination" on a support structure in the rear fuselage. Delamination occurs when repeated stress causes laminated composite materials to begin to separate.
(...)
------------------- It's really easy to quickly find sources.
AD for 787-8 and - 9 ... shimming issues
https://www.federalregister.gov/docu...pany-airplanes
-------------------
That one took a while. I found the 2014 Final report of the Critical Systems Review by FAA and Boeing. So that one addressed earlier findings, the ones from 2012?
I haven't read the report beyond the exec summary. That listed the fuselage, shimming issues in both categories "Design" and "Manufacturing"
Boeing 787-8 Design, Certification, and Manufacturing Systems Review - March 19, 2014 (faa.gov) (PDF file)
Last edited by waito; 30th Apr 2024 at 05:54.
Thread Starter
From The FAA 2014 report:
regarding manufacturing issues fuselage aft section
PDF-page 55 chapter A4.
quote of page 57:
regarding manufacturing issues fuselage aft section
PDF-page 55 chapter A4.
quote of page 57:
Topic: Discrepant shimming on the horizontal stabilizer and aft fuselage sections.Boeing observed numerous production nonconformances in the form of gaps between structural elements and structure pull-up(2) resulting from improper shimming. In the horizontal stabilizer, Boeing identified gaps common to the horizontal stabilizer rear spar terminal fitting. In the aft fuselage (sections 46, 47, and 48), Boeing identified a significantly higher number of nonconformances related to shimming as compared to other fuselage sections with comparable design features. Aft fuselage shimming issues were identified in production and in the full-scale fatigue test.
Observation: No systemic engineering or design/certification issues were identified during the examination of the horizontal stabilizer and the aft fuselage sections.
Although the subteam did not identify systemic engineering or design/certification issues, it reviewed shimming issues directly related to various aspects of the assembly and manufacturing processes. The subteam passed its observations to the Manufacturing/Quality Subteam for consideration during its deep-dive review at Boeing South Carolina (BSC) and Alenia Aeronautica.
A.4.3.CONCLUSION
Boeing addressed the shimming issues identified in fuselage sections 46, 47, and 48 through corrective actions implemented before delivery. However, five airplanes were delivered with potentially discrepant shims in section 48. Boeing issued Alert Service Bulletin No. B787-81205-SB530004-00 with inspection and repair requirements for the affected airplanes in anticipation of an AD; however, all inspections and required corrective actions were completed before AD issuance.
(2)Structure pull-up is a gap between two structural elements resulting from the gap being too large or the structure too stiff. The gap occurs as the structural elements are being fastened together by tightening the bolts to close the gap. Boeing applies Boeing Process Specification BAC5430, "Fabrication and Installation of Resin Bonded Laminated Shims and Solid Fillers,' for the assembly of composite structural elements on the B787 This specification establishes the requirements for fabricating and installing resin bonded laminated shims, solid fillers, and radius fillers as necessary to fill gaps between structural elements during part assembly. The gaps occur between structural elements due to typical part build tolerances
Observation: No systemic engineering or design/certification issues were identified during the examination of the horizontal stabilizer and the aft fuselage sections.
Although the subteam did not identify systemic engineering or design/certification issues, it reviewed shimming issues directly related to various aspects of the assembly and manufacturing processes. The subteam passed its observations to the Manufacturing/Quality Subteam for consideration during its deep-dive review at Boeing South Carolina (BSC) and Alenia Aeronautica.
A.4.3.CONCLUSION
Boeing addressed the shimming issues identified in fuselage sections 46, 47, and 48 through corrective actions implemented before delivery. However, five airplanes were delivered with potentially discrepant shims in section 48. Boeing issued Alert Service Bulletin No. B787-81205-SB530004-00 with inspection and repair requirements for the affected airplanes in anticipation of an AD; however, all inspections and required corrective actions were completed before AD issuance.
(2)Structure pull-up is a gap between two structural elements resulting from the gap being too large or the structure too stiff. The gap occurs as the structural elements are being fastened together by tightening the bolts to close the gap. Boeing applies Boeing Process Specification BAC5430, "Fabrication and Installation of Resin Bonded Laminated Shims and Solid Fillers,' for the assembly of composite structural elements on the B787 This specification establishes the requirements for fabricating and installing resin bonded laminated shims, solid fillers, and radius fillers as necessary to fill gaps between structural elements during part assembly. The gaps occur between structural elements due to typical part build tolerances
