Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- Boeing unlikely to meet FAA’s 90-day deadline for new safety program April 18, 2024
- Focus on quality not slowing innovation, says GKN April 18, 2024
- Boeing defends 787, 777 against whistleblower charges April 17, 2024
- Dissecting Boeing CEO’s statement next new airplane will cost $50bn April 15, 2024
- Bjorn’s Corner: New engine development. Part 3. Propulsive efficiency April 12, 2024
Pontifications: 787 deliveries, suspended a year, look for restart soon
By Scott Hamilton
Sept. 27, 2021, © Leeham News: In a few weeks it will be a year since Boeing suspended delivery of virtually all 787s. Inspections revealed some flaws in production. Despite a year-long effort, Boeing hasn’t been able to persuade the Federal Aviation Administration, yet, to grant authority to resume deliveries.
Deliveries may resume next month, The Wall Street Journal reported Sept. 6. Or they may not. Boeing isn’t making any predictions as it continues to work with the FAA to do so.
More than 100 787s have been produced (it is said the number is 106, but this is a moving target). Boeing continues to inspect the aircraft. Those in production at the Charleston (SC) factory are fixed as these are assembled at a very low rate.
A little gap
Boeing’s marquis wide-body airplane is bedeviled by flaws in mating fuselage sections that are variously described as no bigger than the width of paper, a coat of paint or human hair. Calling these flaws “gaps” conjures up something larger. These aren’t safety of flight issues, meaning the in-service fleet didn’t have to be grounded. (Eight 787s were grounded for inspection and analysis soon after the issue was first discovered in August 2019.) But any in-production 787s went into inventory for inspection and, when necessary, fixes that could include rework. Boeing reduced the production rate, first in response to the COVID pandemic. Later, as inventory grew, Boeing reduced production again to an unspecified rate below 5/mo. (Market sources suggest the rate is now at 2/mo.)
Boeing has a video here explaining some of the processes involved. The target areas are inspected with feeler gauges. Given the widths we’re talking about, I expected that something like a laser might be used. The fix for the planes in inventory involves inserting shims—again, imagine the widths we’re talking about. For planes still on the assembly line, the fixes are incorporated there.
Locations
The affected sections were the aft end of the airplane at Sections 47 and 48. As Boeing investigated further, officials asked the suppliers to inspect their work. Spirit Aerosystems, which makes the nose Section 41, also found similar flaws. Like the aft, corrections of the Section 41 mating require either rework or factory fixes.
Boeing CEO David Calhoun, during an earnings call, described the discoveries and additional revelations as Boeing being tough on itself. The Wall Street Journal reported that Boeing employees representing the FAA, called ODAs (for Organization Designation Authorization), refused recently sign off on a proposed Boeing procedure for spot checks on future airplanes. This delayed restarting deliveries. The target date, according to the newspaper, is now next month.
But Boeing—perhaps stung by the repeated forecasts by former CEO Dennis Muilenburg when the 737 MAX would return to the skies—isn’t making any forecasts. The ODA reticence may also be a newfound backbone following the revelations of FAA acquiescence during the MAX development.
Inexcusable delays
With no 787 deliveries, other than one that pre-dated this problem, for a year, some contracts may run up against provisions that allow the customer to cancel the order without penalty. Contracts have “excusable” and “inexcusable” delay provisions, with specificity for each—along with enough ambiguity at times to allow lawyers to enter the fray. Typically, 9-12 months’ delay is required to kick in these provisions. (Boeing declined to discuss contract terms, but these at a general level are common knowledge within the industry and finance communities.)
Given the pandemic, and now the approaching winter season, some airlines may not want to accept delivery once deliveries restart. But this doesn’t necessarily mean wholesale cancellations are around the corner, either.
More likely Boeing and the customer will negotiate a new delivery schedule rather than cancel.
Production issues from the beginning
It remains unclear why these issues surfaced in 2019 and 2020. The 787 has been in production since 2004 and final assembly since 2007. One would think these issues would have surfaced long before. Coming as they did during the MAX crisis only exacerbated Boeing’s cash flow crunch.
But production of the 787 has been troubled from the start.
Outsourcing that Harry Stonecipher, a former Boeing CEO, insisted on caused no end of grief on the program.
“There were two things going on. One was that not wanting to spend as much Boeing money, but the other thing, if you remember going on back then, was this whole large-scale systems integration phenomenon that was sweeping through the industry,” said a key former Boeing official who was assigned to the 787 program at the creation. The 787 was intended to basically be a prefabricated airplane.
“Yes, and the fact that OEMs could push more design, detailed work, and more of the work down into the supply base” also was a factor. “The OEMs would basically be the conductor and orchestrate everybody else doing the vast majority of the assignment. It turned out not a great idea.”
But the former official said, “It wasn’t complete lunacy because the major partners we picked to a large degree were all OEMs in their own right. Mitsubishi has designed and built all kinds of airplanes, and spacecraft, and rockets, and all that kind of stuff.
“Even Alenia (which gave Boeing fits) was an OEM. It wasn’t that we were completely stupid about it, but what really surprised everybody is that it’s one thing to build a Japanese government fighter or transport plane, it’s another thing to be in charge of a big piece of a commercial airplane. It’s just a completely different assignment.”
Boeing’s own actions
One major problem that emerged was mismatched mating of the wing box to the fuselage. Mitsubishi Heavy Industries designed and built the wing box. Boeing was responsible for mating it with the fuselage.
“We were responsible for the interface between the two of them, and that design flaw that caused about a year’s worth of delay. That was a complete screw-up by Boeing. It was one of those ones that after the static load failed and everybody looked at what happened, it was one of those ‘What in the world? How could we have missed that?’” the official said.
Portions of this information appears in my new book, Air Wars, The Global Combat Between Airbus and Boeing. The book is available here.
Very nice, Scott!
Highly valuable lessons to be learned, for sure.
All the more remarkable that, earlier this year, the first fuselage of the T-7A was mated in less than 30 minutes.
Maybe it was a bit more than the width of a paper.. Many feel-good & play down stories floating in advanced, containment driven PR. A year means something serious, not minor.
Early on I heard stories about hydraulics being used to make things fit, collateral damage.
Hope w’ll see Dreamluners being delivered soon. I guess Boeing is lucky airlines parked so many WB’s & international is still so low.
@keesje
Thanks for dreamluners – spot on
It would appear that this issue doesn’t really center on the gaps themselves but instead centers on the inspection process that BA is trying to use on the gaps. Rather than inspecting 100% of planes on the production line, BA wants to instead “spot check” just 3%. The recent ODA row was caused by the fact that the “selected” 3% were considered to be unrepresentative of a larger batch of aircraft, because the “selected” airframes were produced in relatively close succession to one another — which suggests that the person doing the selection had a poor knowledge of statistics, or perhaps was trying to “cook” the process. In response, a figure of 10% has now been suggested.
Burning question: why doesn’t BA just inspect 100% of the aircraft? Is it afraid of what it will find? The argument can’t logically be about saving time/money because the current grounding has probably wasted more time/money than could ever be gained by reducing the inspection task.
Next question: how come Airbus isn’t having these issues?
@Bryce
It’s hard to argue against inspection of everything – but if BA does so argue why do they argue in such an outlandishly cheatifying way
Does the save money mantra backfire all the time because they do not know how to make aircarts or because they do not know how to inspect/regulate them/the process? Or is this just the same not know
How many not knows before strike out
As for the point raised by SH – it is unclear why these issues surfaced only recently – it would be logical to deduce they emerged because of increased inspection of the role of regulation and inspection, rather than to suppose a technical or any other daylight causality
What’s the loss on the 787 program from this delay, to date, and from speculating any/many future cancellations?
Good news is – no more bears in the woods, probably
“.. but if BA does so argue why do they argue in such an outlandishly cheatifying way ..”
Assume that there is a stealth “payload” hidden.
It is rarely seen that Boeing argues the real causes for their actions.
Usually curative measures are presented as “we did this because $avantage” or “delayed because of $OEM issues” ..
@Uwe
You are right -thanks for this
BA are looking at this the other way round – inspecting everything and singling out the 3% that pass muster- their tactics are indeed brilliant
Plus – no one can say that that’s not truly random, who knows how the 3% turned out ok
“The recent ODA row was caused by the fact that the “selected” 3% were considered to be unrepresentative of a larger batch of aircraft, because the “selected” airframes were produced in relatively close succession to one another — which suggests that the person doing the selection had a poor knowledge of statistics, or perhaps was trying to “cook” the process.”
A truly random selection process will produce sequences such a 3, 8, 11, 12, 13, 14, 23… from time to time. Selection of 3 line numbers in a row is not evidence of ‘cooking’ unless it can be shown that the selection process was non-random.
A simple way to avoid this when selecting 3 aircraft from 100 is to divide the batch into three (consecutive) groups (of 33) and then select a sample from each group: that still leaves the possibility of two samples being relatively close, but the third will — by definition — be much further away.
This isn’t rocket science.
It is isn’t something that can be avoided; it is an inherent property of randomness as humans view it via random number generation. In fact for simple distributions such as linear the absence of sequences that “fail the eyeball test” is an indicator that more detailed analysis needs to be done to validate the RNG because highly random streams will often contain what look to the human eye as improbably sequences or patterns but are just randomness, and if they don’t a human may have been “improving” the output of the RNG making it less random.
In your example you have replaced a selection over a longer run with a binned selection out of 33. Maybe a good idea (I’d check with a statistician on that), but the next thing you will see is that in the fourth group of 33 the selections went 2, 5, 6, 7, 21…
There’s no proof that Boeing selected the three based on random sampling.
Could it be the case that Boeing silently tests ALL frames until they have collected 3% of the production samples shown to pass muster?
i.e. up to 97% could be out of spec.:-) That wouljd be brilliant tactics ( for looking good )!
@ Uwe
Brilliant possibility…you have a devious mind 😉
There are standards for picking samples as a part of batch testing – ISO 2859 is one of them. Just follow a standard and you can justify why you picked the specific samples.
My guess is they picked a few ” Queens for a day ” out of a one week production AFTER making sure there were extra efforts- inspectors- crew to ‘ assure’ ‘typical” unit.
Simply check the crew size and extra help available etc
Just an updated and improved ‘ dog and pony show for the brass ‘
Failures were NOT an option message was “explained ” in extra crew meetings that week
Virtuall all statistical methods are predicated on dozens to thousands of items per hour or per day. NOT on a two per day aircraft with x million parts made by 3 to 10 different major subcontractors involved in ‘ final’ assembly of major sections, etc
Just ask mr post it mcnearney how well that worked. Even if it didn’t- he got a great sendoff and bucu $$$$/month pension to allow retireing in other than wrong side of the tracks
I was working for a Telecom company for a while, and they had some bad data being injected into their database. (for example alphabetic characters being placed into the phone number). I attended a meeting of management, and rather than focus on tracking down the source of the bad data, or ways of filtering the bad data, they were suggesting a weekly report to track how much bad data was getting into the system. I was dumb founded. I found the source of the bad data and filtered it out of the system to be examined in detail by humans. You fix the system, you don’t monitor it. It’s the same way doctors seem to approach some medical problems, let’s take a scan and monitor the problem every 6 months to see if it goes away by magic. They seem scared to actually do something proactively and solve the actual problem.
This is a hammer in hand -> problem? nail! thing.
unix operator -> another layer of indirection 🙂
management -> reports
guy with gun -> shoot to kill
bureaucrats -> another layer of rules.
greens, wingnuts -> excessive micromanagement
….
The really sad part is that I was filling in for a manager on vacation, when I attended the meeting and made the change to the process. When he came back from vacation, the first thing he did was to take my program out of production. He had claimed the bad data wasn’t coming from his system to management. They had a team of 30 people cleaning up the data each month. So, he had been hiding the problem for some time. Sound familiar? Had he even just made up some excuse for the bad data, he could have solved the problem, but, he chose to hide it, moving the problem down the line. Take no responsibility, and hide the data.
back when doing the accumulating front end for MIRO on Rosetta I had about the same issues with JPL people. Size 10 ego on a size 1 amateur.
statistical sampling makes a lot of sense when you are making millions of relatively simple parts using automated processes.
when you are building a giant complex item at the rate of 1-2 a week (at best) there is no justification for statistical sampling. done properly it is just another step in the assembly line and while it may introduce a couple of hours of latency into the end to end process (done properly with automated checkers it would add less than 10 minutes), it would have zero impact on total throughput.
the reason not to check them all would be the anticipated cost of rework on all the defects that are not being caught during the assembly process. which says their assembly process is sh**.
bilbo:
Agreed, I am struggling mightily with the rational for statistical sampling.
see comment below
RE the shimming issue- based on VERY faint-casual observation over two decades ago on 777 body join
Most all ‘ join’ fasteners in the circumferential frames are hiloks- or similar nut breaks off at given torque.
So if frame attached to one section does not ‘match’ second section, then fastener does not pull skin in contact with frame. if the gap is ‘ too large ‘ ( xxx ) then under pressure and tension load the fastener is no longer in simple tension and shear stress but now includes a ‘ leveraged’ bending stress. Dont know how much is too much. To avoid the ‘ lerver action loading and to get back to near simple shear ( mating parts with NO gaps under fastener, a xyz thick shim is needed. Is every fastener so checked around the circumference or maybe every 2nd or third ? Dont know- wont guess. The above is MY simplified view analysis of the basic problem. Would sure help IF someone who actually worked the issue would chime in or correct me.
if on tigthening the fastener the gap closing force is elastic/spring compression type the “gripping tension” will be reduced by that spring force.
Worst case the gap isn’t even closed.
But but but- the power pointless presentation used the techniques of sampling described in stat 101, and worked well on making sure the post-it notes had adequate stickum.
And was what mcnearney suggested.
Each inspection and retrofit could take up to a month, and cost hundreds of millions for each jet, if you multiply that by (up to) a thousand, you’d be sure it sends a shiver down the spines of Calhoun and West, and BA would go bankrupt in no time.
“Burning question: why doesn’t BA just inspect 100% of the aircraft?”
Because the whole quality control system of the B787 possibly rests on a similar statistical sampling policy. If they capitulate on the gap they may find vast proportions of the aircraft require 100%.
William:
Which in fact is a reason for statistical sampling as there could be hundreds if not thousands of spots to do so on.
I am seeing the need for the why (comment below) how it went off the rails is the real issue. It took a shim width issue AND a fuselage section issue.
And missing still is can you have a single shim off clearance wise and be ok, ie. does it have to be a 1 foot circular section off, 1 inch, 1/2 etc.
I think there is a mix of measurements taken and when. You would think interface dimensions are always taken but other dimensions are periodically checked especially those not accessible and require a cut-up of the part to verify some dimensions, especially intricate castings.
@Bryce
On “Next Question” . . . has Airbus solved the problem with 13 A350s grounded at Qatar?
https://www.reuters.com/business/aerospace-defense/qatar-airways-says-regulator-grounds-13-its-airbus-a350s-over-surface-issue-2021-08-05/
It is a different problem but a problem nonetheless.
I believe that was resolved.
As no other reports, possibly a Qatar paint choice that had issues.
https://mobile.twitter.com/Frenchpainter/status/1433111804801081345
@ Javier
It certainly was a problem, but has it:
– Led to a long hiatus on all deliveries of the A350? No
– Led to public quibbling between the OEM and EASA? No
– Led to customers invoking cancellation clauses to as to dump orders? No
– Led to QC employees at the OEM resorting to “whistleblowing”? No
– Thrown a suspicious light upon “shortcut” QC procedures at the OEM? No
A single customer bitched about the problem, EASA said that it couldn’t fine any issue and also indicated a lack of any similar problems at other operators.
A somewhat different category of problem, it seems…
In reference to recent cancellations, LOT – Polish nat’l carrier, has cancelled taking delivery of their last two 787’s from BA. Apparently they were also displeased that Boeing didn’t offer them any compensation for the 737 Max grounding.
That and with the way int’l travel has been trending lately, is a no brainer. They still have 15 of the type in service but Boeing now has to deal with two white tails.
I’m guessing the Q3 results aren’t going to be stellar, unless Defense & Service can carry the company, again. Even Space took a hit, with the valve issues forcing them to roll back the rocket to the assembly building.
One has to wonder how close BA is to taking a charge on the 787 program as each day that ticks by costs them in interest expense and they still have about an $18 billion balance on the program to pay down.
You think guys like Stonecipher and others, who had a hand in changing the mentality from a engineering based company, to a profit focused company – look at what they did and have the littlest bit of regret?
Or am I asking too much?
@Frank
You are asking the impossible : the Stoncipher class know nothing, care less
But elaborate, if you wish, as you have in the past, on the 787 program finances to date and in view of possible/probable cancellations
Some August info for you:
In August, Boeing booked 53 orders consisting of 35 single aisle aircraft and 18 wide body aircraft:
777 Partners ordered 8 Boeing 737 MAX aircraft.
United Airlines (UAL) ordered 8 Boeing 737 MAX aircraft.
Alaska Airlines (ALK) ordered 12 Boeing 737 MAX aircraft.
Bain Capital ordered 5 Boeing 737 MAX aircraft.
An unidentified customer ordered 2 Boeing 737 MAX aircraft.
FedEx (FDX) ordered 2 Boeing 777Fs.
An unidentified customer ordered 10 Boeing 777Fs.
An unidentified customer ordered 7 Boeing 787-9s.
During the month the following changes were made to the order book:
For an order from AerCap for 1 Boeing 787-9, Rolls Royce was selected as the turbofan supplier.
Air New Zealand converted an order for 1 Boeing 787-10 to the smaller -9 variant.
Avolon cancelled orders for 3 Boeing 787-8s.
United Airlines cancelled orders or 20 Boeing 737 MAX aircraft.
An unidentified customer cancelled orders for 20 Boeing 737 MAX aircraft.
Jackson Square Aviation was revealed as the customer for 1 Boeing 737 MAX.
https://seekingalpha.com/article/4456937-boeing-scores-and-disappoints-with-737-max
Frank:
With the Sonciper/Walsh mind set you are asking too much.
You see that over and over again.
As Leeham has said, whole new board and management.
The last I heard about Stonechipher he was tied up with cat lawsuits. I doubt he has much free time to reflect.
https://www.citizen-times.com/story/news/local/2016/08/26/biltmore-forest-lawsuit-over-12-well-loved-cats/89399072/
I thought Stonecipher died, but he didn’t. At least Wikipedia says right up front that he was the start of messing up Boeing saying he wasn’t big on engineering.
Funny thing was that William Boeing and William Allen were not engineers.
At that level it is about managing a company and people.
The issue becomes fatal when you have accountants that just want to maximize profit and as a result destroy the company foundation per Stonecipher and followers .
The engineering should be at the BCA level and the program managers.
CEO and the board needs to listen to the engineers and balance the whole shebang.
Muhlenberg is not an accountant, neither is McNerney.
When I say I changed the culture of Boeing, that was the intent, so it’s run like a business rather than a great engineering firm. It is a great engineering firm, but people invest in a company because they want to make money.
Harry Stonecipher, 2004, former CEO of The Boeing Company, reflecting on the late 1990s
mcnearney was also a welch acolyte – rotten from the head
” When I say I changed the culture of Boeing, that was the intent, so it’s run like a business rather than a great engineering firm. It is a great engineering firm, but people invest in a company because they want to make money.
Harry Stonecipher, 2004, former CEO of The Boeing Company, reflecting on the late 1990s”
add in welch mantra re cutting the bottom 10 percent employees every year or two
And bean counters who can read an org chart
and you get GE,Boeing, 3M, etc
Bryce — “Burning question: why doesn’t BA just inspect 100% of the aircraft? Is it afraid of what it will find?” I think that’s two burning questions and I assume that by ‘100%’ Bryce means all of them: every single one.
Scott — “It remains unclear why these issues surfaced in 2019 and 2020. The 787 has been in production since 2004 and final assembly since 2007. One would think these issues would have surfaced long before.”
Does anyone (reader, that is) know how both difficult and expensive it would be to try to check a couple of random early aircraft retrospectively (if such is possible)? And I seem to remember there were some early test airframes that were scrapped(?) because they could/did not meet acceptable standards for delivery: were known gaps, previously detected in initial production, an issue even then…?
@Pundit
Correcting what seems a serious mistake or fault or procedure will always be expensive, this appears to be inevitable
Better to correct than not to correct, surely not to correct would be more expensive, correction would involve exhausting inspection of every unit produced
One year and counting grounding is expensive, perhaps expensive enough to cause multiple cancellations
How cheap can Boeing afford to be?
To cheap to get the fabrication right, too cheap to correct it?
As @bilbo says above – the only reason not to inspect and the only logical conclusion is that BA assembly is bear in the woods bad
Pundit:
Its clearly not only possible but the directive is to check that on the first major check and correct (those that do not have both tolerances out and are not deemed safety of flight issues as of now)
I don’t think its cheap but have not seen any reporting on the cost (I think they should pull some sample aircraft from the OK fleet and check now, but then that is me not FAA)
Which directive??
One thing I’ve never seen reported is by how much these gaps are thought to weaken the fuselage by 1%, 10%, 20%?
Also it is reported as not a “safety of flight issue”. What does that mean? What % of the tested ultimate load does an aircraft need to retain for it to be considered safe? I imagine metal aircraft weaken as they approach fatigue life so there is provision for aircraft to be able to fly even if not as strong as the ultimate load test would indicate.
I also don’t understand not testing all the of aircraft. It seems either this is something that needs to be addressed, in which case it seems they should all be inspected. Or it is not a big deal in terms of structural impact, in which case why all the fuss? Why not attempt to get larger gaps certified if they have no real impact?
@Scott
> More than 100 787s have been produced (it is said the number is 106
Should that not be 1,000 and 1006 respectively?
That also confused me for a second – 106 awaiting delivery.
@ jbeeko
The figure 0f 106 refers to the batch of 787s produced since the start of the grounding but not yet delivered.
I think these issues did arise in 2007, during final assembly, and possibly earlier, but, were not adequately addressed. And might be bigger than a coat of paint.
================
https://www.seattletimes.com/business/boeing-finds-787-pieces-arent-quite-a-perfect-fit/
I’m fascinated by the following quote in the article above:
“…It was one of those ones that after the static load failed and everybody looked at what happened, it was one of those ‘What in the world? How could we have missed that?'”
The 787 didn’t fail its static load test, so can we assume that this is a reference to the spectacular failure of the 777X load test — featuring blown out door and ruptured fuselage? Is this an admission that BA was seriously caught off guard by that incident?
Bryce, I assume Scott was referring to this event in load testing the 787 wing?
===========
https://www.seattletimes.com/business/boeing-aerospace/boeing-787-wing-flaw-extends-inside-plane/
See https://www.seattletimes.com/business/boeing-aerospace/boeing-787-wing-flaw-extends-inside-plane/
@ Richard D and @ jbeeko
Thank you for the link 👍
> @ Richard D and @ jbeeko
Thank you for the link 👍 <
Ditto; very useful.
It was the 787 wing join that failed so clearly wrong on the assumption. T
.3 of an inch off!!!??? My goodness, Airbus’s tolerances are measured down to .0001! At least that’s what I heard. Wow. Can one even imagine .3 of an inch off on a Dodge? This is what the Seattle paper article stated …
What “assumption” in Bill7’s message — or anyone else’s message — are you referring to…?
Sam1:
You can’t mft a fuselage or wing to .0001. That is insane.
Some internal components of hydraulic pumps and diesel injection systems go down to that level but that is a moving part fit and takes incredibly precision machinery to achieve.
Its worth reading about the Leaning Tower of San Francisco to see how far off things can be!
I worked on a house that was a couple inches off on a 60 foot wall.
The decision was to live with it as the remedial would have meant taking out the back fill, redoing the whole foundation.
In that distance it was not a big fit issue. A bit of custom trimming in the corners.
The 787 started to fail its initial load test at something around 100%. 50 % more to go. Aborted at the time.
it was not the wing, center wing box box failing but details in the wing to body attachment. ( actually the way wing skin stresses were “ferried over” into the center box top and bottom skins. elastic discontinuity leading delamination.
https://www.seattletimes.com/business/boeing-aerospace/boeing-787-wing-flaw-extends-inside-plane/
The immediate fix was weakening stiffeners and then adding titanium “shoes” to channel the stresses.
If Scott will permit a small foray off topic, AirInsight has today published a nice update/summary on the situation vis-à-vis the A350F versus the 777XF:
https://airinsight.com/boeing-and-airbus-ready-for-big-freighter-battle/
Of interest:
“Vice President of Commercial Sales and Marketing, Ihssane Mounir, confirmed several customers are talking to Boeing on the 777XF, he said in a rare interview with The Seattle Times on September 26. “We have several customers talking to us about … the 777FX. (…) Watch this space. Things are gonna happen”, Mounir told the newspaper.
It is most likely that both airframers will make announcements at next month’s Dubai Airshow, where Airbus could reveal the launch customer(s) for the A350F and Boeing could launch the 777XF and announce customers as well. It’s no secret that Qatar Airways is keen to have both new freighters in its fleet.”
Good article Scott, thank you.
Some clarifications for you all to ponder. First, the FAA made the determination, not Boeing, to cease deliveries until this issue is resolved. Deeming this as a “not a safety of flight issue” is frankly unprofessional to say this. Minor gaps, even a minute thousands of an inch in any airframe if not addressed with proper engineering and repair/stress analysis could lead eventually to a possible catastrophic failure as the life cycle of the airframe stresses. Just ask Aloha.
All airframe manufacturers have these gap issues, the engineering drawings will specify the amount of shim tolerance allowed not to exceed. Boeing has been exceeding these shim tolerance hopefully using proper MRB, but the FAA questioned why this tolerance is continuing to be allowed. Eventually the airline operators will experience some sort of fatigue (and caught early enough) and if not a possible failure if not addressed properly. Engineering discipline in manufacturing and in service provides for stress engineering to calculate load paths… I’m thinking this stress for the amount of gap is deemed unairworthy and possibly they have to address having the suppliers make a fix, this takes time to address the approved drawings and implement into production.
Someone asked why Airbus doesn’t have these issues, I counter that they do but their approach is much more proactive and handled with proper program management practices. They stay ahead of curve and work closely with the regulatory EASA and keep them informed.
Just my two cents (sense)
Airdoc said …Just ask Aloha…’
That was a corrosion and inspection issue, not a tolerance-shimming issue.
Aloha 737 fatigue failure – plans for a revisitation? SEATTLE — KIRO Team 7 Investigators discover cracks, corrosion and weakened metal hidden inside a growing number of Boeing passenger jets. The problems lie along structural seams called lap joints. A fuselage is designed with overlapping sheets of metal riveted together.
Though the Aloha incident had a different cause, Airdoc correctly drew a parallel in the sense of:
“…catastrophic failure as the life cycle of the airframe stresses.”
i.e. a flaw that only reveals itself — via catastrophic failure — as a function of cycle count.
Once could surmise that the Denver PW 777 engine issue falls into a similar category: catastrophic failure due to hidden cause that only reveals itself after a certain number of operating hours.
More importantly, non-destructive inspection pushed by OEM failed to catch the fracture in blade.
Airdoc:
All fits have tolerances.
We pay the FAA to assess these issues.
Right now, they have looked at it, done the engineering (or review or had them reviewed) calculations on the affects and made a determination it is ok. That may change.
It is solid engineering approach and totally professional.
Engineering builds safety factors into the design.
Boeing was unprofessional to let it get to this point, but those decisions on safety of flight go on all the time.
The design does not stop at perfect, its is run until they see the failure issue (and its possible that failure would be .010).
.005 would be the safety factor keeping way from .010.
A real world example is a house I worked on. There was a design issue with clearance and a glue laminated support.
When found, the entire first floor as built. The Architect called in the engineer, he assessed and approved as was.
The Glue Lam had a 150% safety factor, the situation cut into that but there was still 20% over build.
The space shuttle seal failure was a case in point where they pushed it to the limit and ok. But then they pushed it again and it failed.
There was a safety factor and it was not the first violation, it was the second that went past all safety factors .
@Bryce,
You are correct about Aloha, but my point being minor/major repairs in airframe, including adding shims if exceeding tolerance could be catastrophic. Airline operators will/should accomplish regular interval inspections to ensure integrity and safety.
As for the PW4000, yes that failure was due of course to fan blade fatigue. Those blades were on inspection intervals, but the interval was calculated too far out.
SWA had two separate fan blade failures both uncontained (cert requires they be contained) on CFM 56-7 engines, one of those failures resulted in the inlet cowl failing and breaking away causing a loss of life when slamming into the fuselage. At the time of the first failure there was not regular blade inspection intervals, but GE developed and determined an inspection procedure to inspect fan blades for fractures…. A few operators complained about these inspections as time consuming and then the second failure occurred. I believe it’s now a regular occurring AD.
In SMS we learn all about risks and managing different levels of risk for mitigation. Sometimes we are not very good at it, or simply ignore it. But in defense of US 121 operators, they do a very good job today with SMS and risk in particular.
Did you know, that we don’t see aging aircraft AD’s on Airbus or MCD airframes? Do you know why?
Some background info. showing how P&W’s TAI was a joke:
Go down to
-> “P&W in keeping with NDI industry practice when implementing a new inspection process classified the TAI as a new and emerging technology and therefore did not have to develop a formal program for initial and recurrent training, certify the TAI inspectors, or have a Level 3 inspector on staff, as is done in other established NDI techniques. The 1st shift inspector was trained by the engineers who developed the process and the 2nd shift inspector, who was the one who last inspected the United Airlines fan blade that fractured, was trained by the 1st shift inspector. Both inspectors stated that their training on the TAI was about 40 hours of on-the-job training. In comparison, the certification requirements for the commonly used eddy current and ultrasonic inspections are 40 hours of classroom training and 1,200 and 1,600 hours of practical experience, respectively.P&W in keeping with NDI industry practice when implementing a new inspection process classified the TAI as a new and emerging technology and therefore did not have to develop a formal program for initial and recurrent training, certify the TAI inspectors, or have a Level 3 inspector on staff, as is done in other established NDI techniques. The 1st shift inspector was trained by the engineers who developed the process and the 2nd shift inspector, who was the one who last inspected the United Airlines fan blade that fractured, was trained by the 1st shift inspector. Both inspectors stated that their training on the TAI was about 40 hours of on-the-job training. In comparison, the certification requirements for the commonly used eddy current and ultrasonic inspections are 40 hours of classroom training and 1,200 and 1,600 hours of practical experience, respectively. […]”
http://aerossurance.com/safety-management/ndi-failures-b777-pw4077-fbo/
@Bubba2,
Thank you. You are correct about Aloha, but I’ll add that the high cycle stress on the airframe contributed. There was shimming in those repairs to fill up the tolerance.
You are aware of the aging aircraft AD’s applicable on Boeing airframes and why that is?
“These aren’t safety of flight issues, meaning the in-service fleet didn’t have to be grounded.”
But what exactly is the consequences? Reduced number of cycles?
Is it likely that the entire in-service fleet needs rework?
> Is it likely that the entire in-service fleet needs rework? <
A good question. BA sure want to minimize the sample,
and given their recent issues..
Meg/Bill7:
Currently stated (subject to change as is any engineering analysis) is that they can go to their first D check with no requirement for sooner. Then correct.
I believe all 787 will get checked at that D check.
If you look at the complexity of the join checks, Boeing has a valid desire to do statistical checks. Its time consuming and costly.
The FAA equally has valid reasons to want to ensure any statistical check is valid in catching problems.
Anyone that deal with statistics knows it can be a disagreement .
Boeing proposed a solution, the FAA disagreed. How far apart they are (pun) we don’t know.
The goal is as few checks as possible that is assessed as catching any drift off specification.
I reviewed the Boeing video from a technician view (.005 gap is a common valve lash setting). Said video had some good tech aspect hidden amid the PR spin.
What I am seeing is to measure what are really clearances and not gaps (that is the common term) is a time consuming and interuptive process.
Ergo, you see the temp fasteners in place (hundreds) remove fasteners to check a clearance, then go to the next one.
Until all your shim locations are inspected, you can’t finish the fastening for that join.
No question that something really stupid or bizarre happened that a programmed machine that put out shims was not quality control checked regularly (again statistical sampling methods get involved but initially you do 100%, set a baseline, then a valid follow up sampling done)
The failure has two parts. The join itself (on that section of fuselage) out of tolerance. That is the most strange part as that is directly measurable.
The join check during assembly you can see the difficulty and delay.
That of course begs some questions as to building in more tolerance to that as an issue. .005 for a fuselage section is pretty much insane for something that size. The only place I know of you achieve better than that is machining of a small part (diesel fuel injection pumps)
And a feeler gauge is an iffy thing in and of itself. Valve lash by a mfg, is best done with a range of allowance.
My Ural happens to use .004 (as did my R80GSE BMW back in the 80s on its air cooled engine on the intake).
The process is by feel. You put in the gauge, then tighten the adjustment screw, torque the hold nut, then see if the gauge moves easily, hard, or just falls out. If it flat falls out its too loose (another shim please, and you have to guess by experience what that shim will be).
Cycles with the bucket and shim method for valve lash were a nightmare as you had to assess, do a trail shim, put the whole valve rack back and torque it, then check again and adjust to a different shim if not right.
For the .004, you use 5 different feeler gauge width (.003 to .007 in .001 steps). Some of those 5 are discounted, but make an adjustment (shim) and you have to measure it all over again
So its not just one check, its probably 3. There is a point where the feeler gauge slide through but is it loose, a bit tight or way tight?
What we are missing is how many shim locations there are. If the whole join has to be .005 all the way around then you could have hundreds (how long can each shim be?) 1/4 inch, half, 2 inches? There is a length limit as you can cross variations that take different shim thickness to deal with a section (which can be very small)
seems to me that for body join areas, the IML ( inner mold line ) IF properly done and contolled would reduce the need for shims. On commercial aircraft OML control can allow small variations with little effect on drag. On B-2 bomber OML was absolutely critical for stealth so most part layups were designed with OML control. Can’t really do both at the same time.
TransWorld said: “It was the 787 wing join that failed so clearly wrong on the assumption.”
To which “assumption” is TW referring?
“..The photos — taken during the ongoing assembly of the first airplane, which is due to roll out in a month — show a gap of 0.3 inch where the nose-and-cockpit section made by Spirit AeroSystems bulged out farther on the left side than the fuselage section behind it, made by Kawasaki of Japan..”
https://www.seattletimes.com/business/boeing-finds-787-pieces-arent-quite-a-perfect-fit/
yeesh..
The stress test failure where the body and wing join are.
Do the tolerances really have to be that tight on the 787? Or is this a case of Boeing shooting itself it the foot by just doing things the way they have always been done without checking if it is really necessary?
Miles:
That has crossed my mind as well. Bjorn might have an idea.
I am going to guess it has a lot to do with the snap it together at the FAL.
Ideally you would need no shimage. But that is stunning fine fit for a non machined part like that let alone a massive fuselage.
I flew quit a few C-15-0/52 and C-172, no two ever flew quite the same and we had one that was pretty strange. Clearly the tolerances on those were quite variable. Not dangerous, but you could tell.
Granted its a huge difference between a Cessna and a commercial jet.
Flip of some of the thoughts is that if the fuselage and shims are out, then they have to ground and fix.
-> “Deliveries of Boeing’s troubled KC-46 tanker were halted for about a month earlier this year after Air Force and company inspectors found a red plastic cap lodged in a fuel valve”
https://mobile.twitter.com/ACapaccio/status/1442539706047098887
Sep. 27, 2021 at 9:53 am Updated Sep. 27, 2021 at 4:46 pm
By
Tony Capaccio
Bloomberg
Deliveries of Boeing’s troubled KC-46 tanker were halted for about a month earlier this year after Air Force and company inspectors found a red plastic cap lodged in a fuel valve that caused the uncontrolled flow of fuel from a one tank into another.
Tanker deliveries resumed after the previously unreported halt once Boeing confirmed that the debris “was missed on the aircraft” before an April 30 delivery flight, according to Captain Samantha Morrison, an Air Force spokeswoman. She said “a shortfall was identified in the previous inspection process, and additional layers of inspections have been added.” The company gave assurances that “future aircraft deliveries” would be debris-free, Morrison said in a statement.
Although deliveries resumed in June, seven serious “Category 1” deficiencies with the refueling tanker are unresolved. “Current plans show delivery of a fully mission-capable KC-46 by fiscal 2024,” she said. That’s 13 years after Boeing won the contract for the program.
In addition to repeated problems with debris, the unresolved problems include flaws in the “Remote Vision System” used to connect the tanker with planes in flight for refueling, a stiff refueling boom, fuel system leaks, issues with the flight management system, cracks in the air refueling drain tube and cracks in the auxiliary power unit drain mast, Morrison said.
“Boeing is making progress on resolving all seven deficiencies,” Morrison said.
Forty-seven of an eventual 175 tankers have been delivered since Boeing won the contract in February 2011.
In the latest incident, a tanker was being flown to Seymour Johnson Air Force Base in North Carolina for delivery when the aircrew discovered an “uncommanded fuel transfer” from one tank to another, according to Morrison. The crew “was not able to stop the transfer of fuel as desired,” she said. The problem “was found to be caused by foreign object debris — a red plastic cap — that had become lodged in the right main tank shut-off valve,” she said.
Boeing said in a statement that the stray cap had been used to protect aircraft components during manufacturing and installation. Across company operations, “we have instituted significant measures, establishing internal controls such as additional training for mechanics and inspectors and ensuring process discipline” to prevent debris incidents, the contractor said. “We have more work to do, and are taking additional actions.”
“Boeing said in a statement that the stray cap had been used to protect aircraft components during manufacturing and installation. Across company operations, “we have instituted significant measures, establishing internal controls such as additional training for mechanics and inspectors and ensuring process discipline” to prevent debris incidents, the contractor said. “We have more work to do, and are taking additional actions.””
==============
Why can’t they simply state what they really are doing, rather than blur the truth with some PR BS? Number the cups with a magic marker, and when the fuel system is connected, account for all of the cups. And/or, make the cup out of a stiff material, that can’t be ingested into the fuel hoses and valves. I’m guessing that they are just telling mechanic’s to “let’s be careful out there” and putting the entire responsibility on them.
Can’t disagree.
Those caps are standard across many fluid industries.
Been more than a few things plug up when a cap or a rag was left in.
Seems to me that a properly sized ‘ grate ‘ ( not a filter ) placed over pump inletS – would at least stop items large enough to jam a valve.
Said strainer requires a large bulge to deal with the need for flow through.
So a cap would also plug the strainer to some degree and then you have restricted flow.
The answer is quality control as its a one off issue that caps are taken off and never put on again for the life of a system.
Strainers are only put in if there is something like a pump breakup that you want to stop getting spread through a system.
Sometimes strainers are used initially and then when the system is cleaned and good to go, removed.
You only want a filter/strainer
Where did Scott give permission to wander off topic into the intricacies of strainers?
You’re ignoring the tenets that you like to preach to others 😏
I’m traveling so I’m not watching this forum all that closely. That said, Children, will you all please behave? Otherwise I’ll close comments.
Hamilton
Transworld said in part
” Said strainer requires a large bulge to deal with the need for flow through.
So a cap would also plug the strainer to some degree and then you have restricted flow. . ..
Good point- but almost any kind of sensor- or comparison as to flow per unit time would show a ‘ lower flow rate” or higher pressure drop. Eventually causing some sort of inspection or comparison as to WTF ?
Even if waiting till the next check would at least prevent such a significant issue as blocking a valve open or closed.
Just my .00000002
duhh, simple, just ..
Sure!
Strainers require service or gum up.
Why can’t Boeing simply state what they really are doing, rather than blur the truth with some PR BS? Number the cups with a magic marker, and when the fuel system is connected, account for all of the cups. And/or, make the cup out of a stiff material, that can’t be ingested into the fuel hoses and valves. I’m guessing that they are just telling mechanic’s to “let’s be careful out there” and putting the entire responsibility on them.
General comment directed at Boeing: slapping the words “Digital” and “Innovation” (boy, am I tired of that latter word) onto Vaporware isn’t going to fly. Not sure they’re trying to fly, though: something else going on at that outfit I think, having little to do with manufacturing commercial passenger aircraft at all.
stay tuned
Boeing has been a national asset, contributing substantially to the GDP of the USA. The failures to execute that exist in nearly every one of their programs is not just a black mark not he company – but endangers the economic welfare of the country. Civil (and even criminal) investigations are required to identify where things went wrong, and how to ensure that it doesn’t happen again.
‘ Boeing has been a national asset’
CORRECT re past tense.
Now its close to a national disgrace/anchor
Their solution is to hire -promote more Jack welch interns and sprinkle in a few ex military or pentagon types and double the size of the DC lobby and make even a bigger Boeing sign on the Building across the street from the Pentagon
In my experience the job of engineering is to ensure that the engineering data (drawings,
CAD models) conform to company and regulatory requirements. The job of QA is to ensure that the airplane itself conforms to the engineering data. One of these two failed in its role, likely QA.
So why were hundreds of planes built and delivered with non-conformances? This calls into question Boeing’s ability to inspect and conform its planes. Does not matter if it is off by the thickness of a hair or a country mile: it either conforms to the drawing or it doesn’t. Not really any gray area here.
This is not like all those complex issues the beancounters at the top face, eg: whether percent of cash flow paid to shareholders should be 90, 100, or 110%, what is the optimal breakdown of this between dividends and stock buybacks, and how many hundreds of millions $ the CEO should get in bonuses for fixing the problems he helped create during his reign on the board of directors.
The sad fact is that after a record of failures that can only be characterized as disgraceful (the Max is only the most recent and spectacular), the cult of ex-GE beancounters which slithered its way into the C-suites on the back of the McD merger, remains in complete control of the company.
For a historical analogy, consider the status of Germany between the wars. Defeat in the First World War banished the kaiser, but did not defeat the forces of radical and violent nationalism. Some of the allies were dissatisfied with ending that war short of Germany’s total defeat and the occupation of Berlin. The shareholder value fanatics are in a similar position as the nationalist fanatics in 1918. They have been momentarily checked by the fiasco of the Max, but they have not been broken or removed from power. They remain in control of the company and ready for a renaissance of their slavish devotion to short term value.
Sadly, history seems doomed to repeat itself, as these dangerous idiots will remain in control till the day they produce a disaster so profound it will sweep them all from power.