Door blows out during ground test on Boeing 777X jet

[BayAreaLondoner]

I don’t think that this has been posted yet but this happened tonight. https://www.seattletimes.com/business/boeing-aerospace/door-blows-out-during-ground-test-on-boeing-777x-jet/Door blows out during ground test on Boeing 777X jetDominic Gates (safari-reader://www.seattletimes.com/author/dominic-gates/)
Sep. 6, 2019 at 6:55 pm Updated Sep. 6, 2019 at 8:31 pm
By Seattle Times aerospace reporter

Boeing’s new widebody jet, the 777X, suffered a setback Thursday afternoon during a high-pressure stress test on the ground when one of the airplane’s cargo doors exploded outward.

One 777X employee working in a nearby bay at Boeing’s Everett plant said he heard “a loud boom and the ground shook.”

The accident happened to what’s called the “static test airplane,” one of the two airplanes in any new jet program that are built for ground testing only and will never fly. It was during the final test that must be passed as part of the airplane’s certification by the Federal Aviation Administration (FAA).

The failure of the door will require careful analysis to find out why it happened, and it may mean Boeing will have to replace the door and repeat the test.

The 777X program (https://www.seattletimes.com/business/boeing-aerospace/the-big-jet-behind-everetts-big-doors-boeing-readies-first-777x-to-fly-next-year/) is already delayed due to a problem with development of the GE-9X engine that will power it. In July, Boeing CEO Dennis Muilenburg revealed on a quarterly earnings call that the first 777X intended to fly, which rolled out of the Everett factory in March, will not make it into the air until next year (https://www.seattletimes.com/business/boeing-aerospace/boeing-says-737-max-crisis-could-temporarily-shut-down-renton-production/).

This ground test failure is another blow.

The static test plane is the one that is deliberately stressed well beyond the limits of normal service. The airplane is surrounded by a metal framework while weights passing through pulleys are fixed to the wings and other parts of the airframe.

During the ultimate load test, the wings are then pulled upward. To pass the test and be certified, the wings must bend without breaking until the load on them reaches at least 150 percent of the normally expected load.

In addition, the skin panels that cover both the wings and the fuselage are pressurized to the maximum stress that would be expected at the edge of any extreme maneuver anticipated in service. The pressure is ratcheted up by pumping air into the cabin.

Sometimes this final test is continued beyond the 150 percent load target until a wing actually breaks. But not always. The carbon-composite wings on the 787 Dreamliner are so flexible that when Boeing tested those in 2010 they bent upward by about 25 feet and, having comfortably surpassed the target load, Boeing halted the test without breaking them.

The massively larger wings of the 777X are also carbon composite, with a folding tip, and during Thursday’s test those must have flexed in a similarly impressive way to those of the 787. This time, however, though the wings did not give way; it was one of the doors that failed — an outcome that is definitely not supposed to happen.

The entire area around the static airplane is typically cleared during this test, with all the measurements taken by monitoring equipment and with engineers watching anxiously on a video link as the load slowly inches up toward the target and the pressure increases.

No one was injured in Thursday’s door explosion, which happened shortly after 1:30 p.m., and everyone was able to exit the building.

On Friday, according to Boeing employees, caution tape was attached to all the entry doors and no one was allowed into the building.

After the incident was first reported Friday by KOMO News, Boeing confirmed that a serious incident had occurred but offered few details.

“During final load testing on the 777X static test airplane, the team encountered an issue that required suspension of the test,” it said in a statement. “The event is under review and the team is working to understand root cause.”

Boeing went on to emphasize that “the testing conditions were well beyond any load expected in commercial service” and that the plane used in the test “will never fly or be used in passenger service.”

Because the GE engine issue has already pushed the jet’s flight tests into next year, it’s possible Boeing may have time to analyze and redo the ultimate load ground test without a further hit to the schedule.

Dominic Gates: 206-464-2963 (tel:206-464-2963) or [email protected]; on Twitter: @dominicgates (https://www.twitter.com/dominicgates).

[UltraFan]

The real blow to Boeing, though, is that in all their years in Seattle, they failed to raise a new generation of aviation journalists. In the heart of American civil aviation you'd expect slightly higher standard of reporting.

[BayAreaLondoner]

Odd to test wings with the cabin pressurised?

No but the way I read it, they seemed to be tying wing testing to destruction to the door blowing off. Or maybe it is just late and I should re-read it.

[FlightlessParrot]

No but the way I read it, they seemed to be tying wing testing to destruction to the door blowing off. Or maybe it is just late and I should re-read it.

I think the piece confuses or combines stress testing and pressure testing, as in this passage:

" During the ultimate load test, the wings are then pulled upward. To pass the test and be certified, the wings must bend without breaking until the load on them reaches at least 150 percent of the normally expected load.

In addition, the skin panels that cover both the wings and the fuselage are pressurized to the maximum stress that would be expected at the edge of any extreme maneuver anticipated in service. The pressure is ratcheted up by pumping air into the cabin."

I don't think that however early you get up in the morning, that passage is going to make sense.

[Dave Therhino]

The article is a bit amateurish. Even with the poor article information, it's clear that the test they were doing was the positive g wing loading ultimate load test. Ultimate load is defined as 1.5 times the limit load. I don't know what limit positive load factor is used for the new 777, but it is required to be at least 2.5 g. So their target was to apply loads corresponding to the airplane pulling at least 3.75 g. That test is required by regulation to be done with the fuselage pressurized to the maximum cabin pressure differential. They apparently got a surprise before they made it to the target load. They are trying to give the impression that the door just popped out. However, plug doors don't just pop out. I suspect some significant structural failure of the fuselage occurred to cause the door to be released like that.

[MemberBerry]

They are trying to give the impression that the door just popped out. However, plug doors don't just pop out. I suspect some significant structural failure of the fuselage occurred to cause the door to be released like that.

Are the cargo doors on the 777X plug doors? That seems unlikely. The doors from the 777-300ER don't seem to be plug doors:

https://i.ytimg.com/vi/539ZeAbu7yk/maxresdefault.jpg

[DaveReidUK]

They are trying to give the impression that the door just popped out. However, plug doors don't just pop out. I suspect some significant structural failure of the fuselage occurred to cause the door to be released like that.

Underfloor container hold doors on widebodies are rarely plug-type. They certainly aren't on the current 777 and I'd be very surprised if they are on the 777X.

I would suspect an issue with the locking mechanism rather than any significant structural failure.

[Dave Therhino]

I know the article above says cargo door, but from other articles I had the impression it was one of the main cabin doors that had failed. I don't know if that's correct.

[Bend alot]

Underfloor container hold doors on widebodies are rarely plug-type. They certainly aren't on the current 777 and I'd be very surprised if they are on the 777X.

I would suspect an issue with the locking mechanism rather than any significant structural failure.
I would expect max diff will have been tested prior to wing loading. If that is true it is not a locking mechanism failure, but stuff is bending/breaking in the structure when wing loading is applied.

[Dave Therhino]

I would expect max diff will have been tested prior to wing loading. .

I believe that is correct. The wing bending test is usually taken to a destructive result, so it is usually planned to be the last test performed on that test airplane.

[Stuart Sutcliffe]

I would expect max diff will have been tested prior to wing loading. If that is true it is not a locking mechanism failure, but stuff is bending/breaking in the structure when wing loading is applied.

No, that isn't necessarily the case, surely?. Tension applied for a wing loading text could just as easily distort part of any door locking mechanism (load transmitted through the airframe, of course) such that the locking mechanism gives way, rather than the airframe.

[DaveReidUK]

I know the article above says cargo door, but from other articles I had the impression it was one of the main cabin doors that had failed. I don't know if that's correct.

Many of the reports on the Net say simply "a door", but I haven't seen any that contradict the Seattle Times article and explicitly identify it as a passenger door.

[Bend alot]

No, that isn't necessarily the case, surely?. Tension applied for a wing loading text could just as easily distort part of any door locking mechanism (load transmitted through the airframe, of course) such that the locking mechanism gives way, rather than the airframe.
If the airframe distorts to break part of the lock mechanism, I will call it a airframe structural failure.

Beefing up the lock could work, but is a band-aid.

If that is the problem and not just a new problem now the FAA have been woken.

[OldLurker]

If the airframe distorts to break part of the lock mechanism, I will call it a airframe structural failure.

Beefing up the lock could work, but is a band-aid.

If that is the problem and not just a new problem now the FAA have been woken.Let's hope the FAA have been properly woken. I’m surprised that nobody has mentioned the DC-10 yet.

[DaveReidUK]

I’m surprised that nobody has mentioned the DC-10 yet.

Probably because it's highly unlikely that any of the factors that contributed to the AA or TK accidents were present in this latest event, despite the outwardly similar (npi) outcome.

[Bend alot]

Let's hope the FAA have been properly woken. I’m surprised that nobody has mentioned the DC-10 yet.
At least they were present, but surprised they were "quiet" after the event. I would expect they would have had questions.

[Speed of Sound]

No, that isn't necessarily the case, surely?. Tension applied for a wing loading text could just as easily distort part of any door locking mechanism (load transmitted through the airframe, of course) such that the locking mechanism gives way, rather than the airframe.

The door locking mechanism in that case would be the part attached to the doorframe rather than the door. That cannot be done without distorting the part of the airframe that the mechanism is attached to.

[ManaAdaSystem]

Many of the reports on the Net say simply "a door", but I haven't seen any that contradict the Seattle Times article and explicitly identify it as a passenger door.

Boeing’s new widebody jet, the 777X, suffered a setback Thursday afternoon during a high-pressure stress test on the ground when one of the airplane’s cargo doors exploded outward.

When you bend the wings, surely that will affect the body as well?

[DaveReidUK]

When you bend the wings, surely that will affect the body as well?

Well yes, but beyond the centre wing box probably not that much. It's possible, of course, that the reason the door let go isn't connected with the wing flexing.

https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/450x333/boeing_777_centre_wing_box_396d2064121c9d3b3be6bfd648d1051a1 c36d438.jpg

The "least worst" outcome for Boeing, it terms of its effect on the development programme, would be if it turns out to be an unrelated defect with the locking system that manifested itself at 150% of max cabin diff (still not good news, of course). I'm not familiar with the 777 cargo door, but looking at photos it appears to use a fairly standard combination of C-latches and shoot-bolts, which are normally pretty robust and reliable.

[golfyankeesierra]

.....The "least worst" outcome for Boeing, it terms of its effect on the development programme, would be if it turns out to be an unrelated defect with the locking system that manifested itself at 150% of max cabin diff......
And the “worst worst” outcome will be when it turns out to be exactly the same design as the current gen B777. (Á la B737-trim-wheel-size issue).

[Smythe]

several tests, static load test, final load test, and ultimate load test. I seem to remember final load test was 75% of ultimate? For ultimate, they take it to the ultimate load, and hold for 3 seconds....it appears from the press, it failed under final load, and they never got to ultimate...

Then, there is the "official" word from Boeing..

New York (AFP) - Boeing has suspended testing on its new long-haul 777X aircraft, the company said Friday, a setback that comes as it battles to rebound from the crisis surrounding the 737 MAX.

The so-called "final load" tests are part of the aircraft certification process, overseen by inspectors from the Federal Aviation Administration (FAA), and meant to subject the plane to "loads and stresses well beyond normal operational loads," a Boeing spokesman told AFP in an email.

https://news.yahoo.com/boeing-suspends-testing-long-haul-777x-aircraft-013019287.html

"During final load testing on the 777X static test airplane, the team encountered an issue that required suspension of the test," the spokesman said.

"The testing conditions were well beyond any load expected in commercial service. The event is under review and the team is working to understand root cause."

[misd-agin]

At least they were present, but surprised they were "quiet" after the event. I would expect they would have had questions.

They would have a lot of questions in private. How often do we see the FAA announcing failures during the construction or testing process? Probably never. They leave that up to the corporate PR folks.

[GordonR_Cape]

And the “worst worst” outcome will be when it turns out to be exactly the same design as the current gen B777. (Á la B737-trim-wheel-size issue).

The 777X wing-box is definitely not the same as the 777 design: https://www.flightglobal.com/news/articles/subaru-gears-up-for-777x-with-eye-on-efficiency-co-454156/
Shoichiro Tozuka, president of Subaru’s aerospace unit, notes that the aluminum/titanium wing box that the company produces for the 777-8 and -9 is considerably heavier than that it builds for the legacy 777 programme.
He adds that the new wing-box uses considerably more titanium than the previous 777 wing-box. “We use a lot of titanium parts, which we have experience with from 787 center wing-box production.”

[DaveReidUK]

The 777X wing-box is definitely not the same as the 777 design: https://www.flightglobal.com/news/articles/subaru-gears-up-for-777x-with-eye-on-efficiency-co-454156/

GYS was referring to the cargo door locking system. I'd be surprised if that is much different from the current 777's.

[Aihkio]

When the wing has the max +g load the fuselage has a high bending load tension at the top. A heavy landing might cause slightly higher bending moment but the sense is the same. I have never calculated the shear but I expect a heavy landing would be the worst case.

Freight doors being at the lower half of the hull would require some strange shape changes to pop off as it would be under longitudinal compression.

[Easy Street]

When the wing has the max +g load the fuselage has a high bending load tension at the top. A heavy landing might cause slightly higher bending moment but the sense is the same. I have never calculated the shear but I expect a heavy landing would be the worst case.

Freight doors being at the lower half of the hull would require some strange shape changes to pop off as it would be under longitudinal compression.

Isn’t that only true in flight? During a static test of the wings there will be no bending of the fuselage as the centre section is pinned down to oppose the wing-bending force. Circumferential distortion, maybe...

[Aihkio]

It depends on the test restraints. If only the wing and center wing box were to be tested there would be no reason to have the fuselage there at all. From strength calculation point of view the box is not that difficult, the fuselage part connecting to it is.

[Speed of Sound]

I don't have any experience of this kind of testing but surely between the various phases (such as wing load test and pressure tests) the entire airframe would be checked over for any unintended damage as a result of the previously completed test forces.

Isn’t this much more likely to be a single event such as a damaged, poorly fabricated, mis-aligned or poorly installed locking mechanism? (if indeed it was the lock mechanism which failed)

[edmundronald]

Let's hope the FAA have been properly woken. I’m surprised that nobody has mentioned the DC-10 yet.

Indeed. The issue is not a single test failure - that's what tests are there for. The issue is whether Boeing is going to identify the cause of the failure and ensure that it doesn't propagate through to the airframes that get put in service. After the 737 MAX MCAS debacle, the company is now known to be a bit hurried with its fixes, while the FAA plays the role of a cheerleader for the single major US vendor.

Edmund

[lomapaseo]

At least they were present, but surprised they were "quiet" after the event. I would expect they would have had questions.

more likely "call us when you're ready to submit a new cert plan" meanwhile we'll shuffle some of our manpower to something else.

[Speed of Sound]

Before we get too hard on Boeing over this incident, let’s not forget that the whole point of this kind of testing is to break stuff on the ground so that it doesn’t break in the air.

[Aihkio]

Testing is done to catch design mistakes and for final verification. Still a door popping off/open during wing testing sounds a bit strange.

[Bend alot]

Before we get too hard on Boeing over this incident, let’s not forget that the whole point of this kind of testing is to break stuff on the ground so that it doesn’t break in the air.
Computer modelling and much over the years placed on it - is just not what it was expected to be.

[DaveReidUK]

Still a door popping off/open during wing testing sounds a bit strange.

A door popping off/open at any time sounds a bit strange ...

But possibly slightly less strange if it happens when the fuselage is pressurised to 150% of max diff, as was the case here.

[Back at NH]

From the original 777 test programme showing the wing bend causing rippling of the fuselage.

https://www.youtube.com/watch?v=Ai2HmvAXcU0

[lomapaseo]

From the original 777 test programme showing the wing bend causing rippling of the fuselage.

https://www.youtube.com/watch?v=Ai2HmvAXcU0

I like the last comments "Which ever way you looked at it, the test was a success" then I though about the views out my window seat

[NWA SLF]

This sounds exactly like the DC-10. Cargo door blow out in pressurization test, cabin floor collapsed. Analysis showed mechanics had not completed the latching process. Convair, subcontractor for the fuselage, performed a FMEA, said this is going to happen in production because the latching mechanism is a Rube Goldberg affair. MD altered the FMEA before submitting to the FAA. Result was first AA96 incident over Windsor, Ontario, in which the pilot was able to save the partially loaded plane. Next was TH 981 over Senlis, France, in which 346 people died. Lawsuits unveiled agreement between FAA chief and MD CEO not to issue an AD after the Windsor incident so 346 people were sentenced to death. Lawsuit uncovered the true Convair FMEA prior to MD doctoring it before submission. Resulted in the beginning of the end of MD. Hopefully Boeing remembers the lessons learned that resulted in them becoming the owner of a decimated McDonnell Douglas.

[Smythe]

Sources told Harger that the door came flying off when Boeing was testing the maximum cabin pressure, whilst the aircraft was positioned in its test rig.

"The accident happened to what’s called the “static test airplane,” one of the two airplanes in any new jet program that are built for ground testing only and will never fly. It was during the final test that must be passed as part of the airplane’s certification by the Federal Aviation Administration (FAA).

On Friday, according to Boeing employees, caution tape was attached to all the entry doors and no one was allowed into the building."


The cabin should have been tested several times before now...this was the final test, not the first. It will be interesting to see what phase of the testing the failure happened, how close to final or ultimate load it got.

Blowing your stuff up on the final cert test in front of the FAA and probably a bunch of international certification regulators....damn.

[DaveReidUK]

This sounds exactly like the DC-10.

Based on what little we know so far, it's highly unlikely that any of the factors that contributed to the AA or TK accidents were present in this latest event, despite the outwardly similar (npi) outcome.

[Less Hair]

Didn't they flatten the frames inside the X-cabin in order to win some inches of cabin diameter for the 777X? And hasn't the floor structure material been modified compared to the -300ER? Methinks it's made of CFRP now. Might lead to different bending under extreme cabin pressure?

[DaveReidUK]

Didn't they flatten the frames inside the X-cabin in order to win some inches of cabin diameter for the 777X?

Thinner insulation and redesigned sidewalls. Nothing structural.

[UltraFan]

Don't want to interrupt but do we now know which door blew out? I would really want to know not only if it's passenger or cargo but which one of those. It could be an emergency exit. Now THAT would be very interesting.

[Aihkio]

CFRP allows a higher design strain than Al which is mostly beneficial. Non circular fuselage section would cause quite large displacements due to pressure, especially flattening to gain some space in the cabin floor area would put the floor in compression when the hull is pressurized. While I can think of ways to manage that it does not sound like a very good idea.

[SteinarN]

Thinner insulation and redesigned sidewalls. Nothing structural.

I would say redesigning the fuselage frames making the frame height lower but probably increase the thickness of the material in the frame in order the make the cabin wider is a significant structural modification.

[Aihkio]

Changing the frames is a design cycle, while not necessarily a major change it would still be far from trivial.

[tdracer]

Thinner insulation and redesigned sidewalls. Nothing structural.

The fuselage redesign was most definitely structural - they made the side wall structure 'thinner' to open up more interior space.

As Aihkio notes, I wonder if it is related to how the fuselage was being held down. When they did the ultimate load test on the 767 nearly 40 years ago, they never broke the wings because the fuselage broke first. They were already above the 150% load limit when the fuselage let loose so they didn't need to repeat the test.

[Water pilot]

This starts to restore my confidence in Boeing. The occasional <censored> moment during testing means that you are really testing, rather than going through the motions. Something valuable was learned, and not the hard way. The shareholders don't like this sort of thing but they can get stuffed. People actually have to fly this plane so let's make it as safe as possible. It will get done eventually.

I wonder if this means that they have to build a new test frame?

[Raffles S.A.]

I suppose a picture of the blown out door has not yet been leaked?

[Sailvi767]

The article is a bit amateurish. Even with the poor article information, it's clear that the test they were doing was the positive g wing loading ultimate load test. Ultimate load is defined as 1.5 times the limit load. I don't know what limit positive load factor is used for the new 777, but it is required to be at least 2.5 g. So their target was to apply loads corresponding to the airplane pulling at least 3.75 g. That test is required by regulation to be done with the fuselage pressurized to the maximum cabin pressure differential. They apparently got a surprise before they made it to the target load. They are trying to give the impression that the door just popped out. However, plug doors don't just pop out. I suspect some significant structural failure of the fuselage occurred to cause the door to be released like that.

Most cargo doors are not plug type.

[DaveReidUK]

The fuselage redesign was most definitely structural - they made the side wall structure 'thinner' to open up more interior space.

I stand corrected - I would agree that thinner profile frames are indeed structural (as opposed to sidewalls, which aren't).

[aircarver]

Back when we (Fairchild-Republic) were testing the Swearingen Metro 4, the cargo door blew off, and sailed 50 feet across the lab ... The area was un-occupied so no harm, no foul, but after that, a cargo net blocked it's path in case there was a repeat ...

[Sailvi767]

The A380 wing failed below the 1.5 limit in testing. It’s not uncommon to have issues in the testing phase. I don’t believe they even retested the A380 wing. That is after all the point of testing. Could be no design changes are required or it could be a major engineering effort. At this point no one knows.

[Smythe]

Point of clarification here.

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

They were simply doing the cabin pressure test while it was on the stand. (which was prudent, given the results)

As far as when it failed in the test, will be the issue. If it failed under static, or final load test, that is a huge problem. If it failed on ultimate (150% of final load) that is not such an issue, just depends at which pressure it failed.

As a side note, given this was a new airframe, with few compression cycles...it should have handled the loads no problem...an airframe with many compression cycles..that is different...this really could be an issue, but who knows.

I suppose a picture of the blown out door has not yet been leaked?
Press noted Boeing locked the facility down. Employees showing up on Friday were not able to access the building.

[ozslf]

From memory (documentary on previous similar tests and FEA modelling a long time ago), testing achieves the following:
- shows the design and construction matches model predictions during normal conditions (say up to working loads)
- shows the same up to design loads (often working plus a percentage e.g. 150% of cabin differential)
- shoes the reliability of the model at the extreme edges (testing to failure)

When testing to failure, you often find out if the nonlinearities in real life were adequately built into the model (think of all the various stresses causing strains and deflections in different directions combining with each other) and - hopefully - you have correctly predicted the weakest point and failure mode at which structure eventually fails.

[DaveReidUK]

Point of clarification here.

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

They were simply doing the cabin pressure test while it was on the stand. (which was prudent, given the results)

That appears to contradict the Komo News report (on which the Seattle Times article is based):

A door blew off a Boeing 777X as the new plane was undergoing what was supposed to be its final structural inspection by federal regulators.

The test is meant to push the plane beyond its limits. Engineers had the plane pressurized and on the ground. They loaded it up well beyond capacity and bent its wings in an extreme manner, in a way almost certain to never happen in the real world.

As the ground test was underway and as engineers and FAA inspectors watched, a door blew off the plane.

Door blows off Boeing 777X during stress test (https://komonews.com/news/local/door-blows-off-boeing-777x-during-stress-test)

It's hard to imagine a bunch of FAA inspectors watching just a simple pressurisation test. What's your source for the alternative account ?

[Water pilot]

I guess I understand why they locked the building down but I think it is a mistake. Usually you don't want that picture of what is a fairly normal sort of engineering snafu (this would hardly be a story except for the MAX) out there with scary headlines, but one of the big problems with the whole MAX debacle was the lack of transparency and circle the wagons approach to the disaster by Boeing. If they let the press in to sniff around and made engineers available, I think it would go a long way to reinforcing the "Boeing comeback" narrative that we need to start seeing pretty soon. "This highlights our commitment to building the safest planes ever", "the engineers are back in charge", "we won't release it until it is right" sorts of PR taglines practically write themselves.

What are they worried about, the stock is going to take a short term hit?

[lomapaseo]

I guess I understand why they locked the building down but I think it is a mistake. Usually you don't want that picture of what is a fairly normal sort of engineering snafu (this would hardly be a story except for the MAX) out there with scary headlines, but one of the big problems with the whole MAX debacle was the lack of transparency and circle the wagons approach to the disaster by Boeing. If they let the press in to sniff around and made engineers available, I think it would go a long way to reinforcing the "Boeing comeback" narrative that we need to start seeing pretty soon. "This highlights our commitment to building the safest planes ever", "the engineers are back in charge", "we won't release it until it is right" sorts of PR taglines practically write themselves.

What are they worried about, the stock is going to take a short term hit?

Probably not locked down, just restricted access to post-test investigation only, else all local employees would come take a look kicking through the debris BTDT

[sockfocksAP]

Didn't they flatten the frames inside the X-cabin in order to win some inches of cabin diameter for the 777X? And hasn't the floor structure material been modified compared to the -300ER? Methinks it's made of CFRP now. Might lead to different bending under extreme cabin pressure?
​​​​​​
The original floor grid is CFRP as is the new 777x floor grid. The cabin is the same diameter because the floor beams are the same width dimension wise. It's possible they may have squeezed some extra width from the inside plastic wall linings but seriously doubt they made the frames thinner. Most of the changes are due to wing changing to CFRP.

Edit: ok I stand corrected. Boeing site says additional 2" on each side for a total interior width that is 4" wider than legacy 777. I will have to see if the frames were changed.

Another possible issue is the cabin altitude is designed to be 6000ft similar to the 787. That would increase pressure on the structure especially at more than 100% load. Not sure what cabin altitude is for 777 legacy.

[fdr]

Prior B777 FWD and AFT main cargo doors had piano hinges, and are therefore non plug doors. The AFT BULK door is an inward swinging plug door. The main cabin doors are outward opening plug doors.

A blow out of a MCD could require a failure of the structure around the door to occur, That could occur through failure around the #3 doors when subjected to both high differential pressure and distortion from wing bending testing... sure would be interesting to look at. The wing tests load transfer to the region of the cargo doors does not appear likely, to the extent needed to defeat the locking mechanism. A simple failure from overpressure of the locking mechanism, with or without structural compromise of the primary structure is improbable, TBC has been building that structure for some time, and that doesn't appear to be a new generation technology application.

TBC will know already exactly what happened, and what is needed to rectify the problem. If it s production process defect, it wont take long. If it is a structural issue around the door it will take longer but it won't be a major schedule disruption. Photos and video will tell an interesting story, as will the structural evidence.

[Volume]

Frames were changed from sheet metal to milled aluminum and reduced by 2" thickness each, giving a total of 4" additional space.
So they might be as strong as on the "traditional" 777 but more flexible (stiffness increases at the order of 4 with thickness), causing more deformation to the door surround structure and putting more loads on the locking system.
We will see.

At 787 times we would already had all the pictures circulating the web...

[Bend alot]

Highlighting Boeing's resistance/reluctance to be transparent, no wonder other World regulators are looking like giving the MAX a good look over prior to a stamp.

Certainly some pressure needs to be put on the top management at Boeing to change path and stop heading for the cliff, while saying all is well every second day.

By the time it comes to the "final test" if you do not know the outcome in advance, it is just another game of cards - this aircraft is not a pioneer, it is using known materials and methods it is not experimenting with cutting edge technology or methods.

[Less Hair]

Not a pioneer? It's robot built CFRP-Wing and engines are the latest top technology on the market.

[Aihkio]

Surprising how things change with latitude, our beams change stiffness to the third power of height. (Sorry, couldn't resist.) Anyway stiffnesswise even small changes cause large results and it is beyond normal mortal intuition.

[ATC Watcher]

H- this aircraft is not a pioneer, it is using known materials and methods it is not experimenting with cutting edge technology or methods.
But it follows the same pattern as with the Max, i.e. stretching an existing air frame possibly a bit (too?) far.
Changing structural elements' material composition and thickness to gain space and weight looks wonderful on paper I am sure.

Anyway the key figure we miss here is at what percentage of what ( pressurization or wing bending,) the door failed , if it is close or above to 150% there might be nothing much to write about.
I remember the A380 wing failed at 145% , which was , according Airbus : " within 3% of the set 1.5 limit " and therefore deemed acceptable by the regulator .

[Bend alot]

Not a pioneer? It's robot built CFRP-Wing and engines are the latest top technology on the market.
Robot building is not new or cutting edge if you put BS in, BS comes out - it should be a step forward not backwards. The first 777 passed the test no problem (many years ago).
Wings are not a massive design/construction difference from the 787.
Engines (not made by Boeing) have been used as the excuse to delay - Gas turbines are not new, extracting the last % from them is not new either (yes it is very big, but so is the A380).

The 777X is not much different to a change from a 737 classic to a 737 NG (hopefully not a MAX) as a comparison. It is simply tweaking current and past technology.

After all it is using grandfathering, so a pioneer it is not - just a sibling.

The 747 was a pioneer but the A380 was not

[Less Hair]

Folding wingtips on the 787? If you go into details technology IS pioneering. That is why the engines have teething troubles.
Admittedly not so much the fuselage.

[Bend alot]

Folding wingtips IS pioneering.
.

Certainly for an aircraft designed in the 21st century, exactly the same pioneering level as a moon landings in the 21st century.

The mechanics and materials even design is not new.

[Deepinsider]

Certainly for an aircraft designed in the 21st century, exactly the same pioneering level as a moon landings in the 21st century.

The mechanics and materials even design is not new.

That's true, But what is new, is that same old design (" The first 777 passed the test no problem (many years ago").
is now being pressurised to a HIGHER LEVEL to satisfy marketing policy that the cabin alt will be lower, similar to
the 787.
Somebody here will tell us the pressure differential increase I'm sure.

[Bend alot]

That's true, But what is new, is that same old design (" The first 777 passed the test no problem (many years ago").
is now being pressurised to a HIGHER LEVEL to satisfy marketing policy that the cabin alt will be lower, similar to
the 787.
Somebody here will tell us the pressure differential increase I'm sure.
Yes exactly and since the original 777 there have been great advancements in mathematics, it has been hard for most to keep up.

[DaveReidUK]

Somebody here will tell us the pressure differential increase I'm sure.

The difference between a 6,000' and 8,000' cabin [ISA] is 0.86 psi, so a 150% proof test would require about a 1.3 psi difference.

[Deepinsider]

The difference between a 6,000' and 8,000' cabin [ISA] is 0.86 psi, so a 150% proof test would require about a 1.3 psi difference.

We all know only too well with the kid's balloons what happens with that 'last extra puff'

[Jim59]

Quote:Originally Posted by Deepinsider https://www.pprune.org/images/buttons/viewpost.gif (https://www.pprune.org/rumours-news/625310-door-blows-out-during-ground-test-boeing-777x-jet-4.html#post10564738)Somebody here will tell us the pressure differential increase I'm sure.The difference between a 6,000' and 8,000' cabin [ISA] is 0.86 psi, so a 150% proof test would require about a 1.3 psi difference. Assuming no increase in ceiling.

[golfyankeesierra]

But why are they still doing these test in the first place?
I thought the airplane should have been flying already, if it only wasn’t for engine troubles beginning this year?
Apparently the tests were overdue already. Boeing is not telling everything here.

[Sailvi767]

But why are they still doing these test in the first place?
I thought the airplane should have been flying already, if it only wasn’t for engine troubles beginning this year?
Apparently the tests were overdue already. Boeing is not telling everything here.

Many test can and normally are done concurrently with flight testing. As a example the A380 first flew in Apirl of 2005. The wing failed testing in Feb of 2006.

[Speed of Sound]

I thought the airplane should have been flying already, if it only wasn’t for engine troubles beginning this year?
Apparently the tests were overdue already. Boeing is not telling everything here.

Not necessarily.

The engine delay may have allowed the testing to be rescheduled to fit the extended gap, taking pressure off those doing the testing and allowing more time for fixes if needed.

[FullWings]

...Boeing went on to emphasize that “the testing conditions were well beyond any load expected in commercial service” and that the plane used in the test “will never fly or be used in passenger service.”..
Given that they likely have more lawyers than engineers at Boeing these days, reading between the lines it might have failed above normal max diff but below certification limits...

[golfyankeesierra]

Sailvi and SoS, thanks. Glad that there is no reason to be suspicious.

[fdr]

The 747 was a pioneer but the A380 was not

I would have thought that the use of a ceramic composite skin was pioneering on the 380. It certainly raised some interesting papers on interstitial corrosion and the attendant forces that develop within a laminate. The 787 was also up there with dealing with composite repairs in the field from ramp rash etc.

[wiedehopf]

In regards to the A380:
5000 psi instead of 3000 psi is sort of pioneering, at least in regards to civil airliners.
So is gust alleviation by controlling individual aileron panels.

[Smythe]

Folding wingtips on the 787? If you go into details technology IS pioneering.

Folding wingtips have been an option on the 777-300 since it was introduced. (2004)

Boeing was so sure airlines would buy it that the first 150 or so aircraft had the mechanism built into the wings.

Not a single airline ordered the option.

[Less Hair]

Those were entire outer wing sections folding up. To park at LGA IIRC.
This time it's more like just the raked wingtips folding (no moving parts in the folding section).

[Volume]

But why are they still doing these test in the first place?
I thought the airplane should have been flying already, if it only wasn’t for engine troubles beginning this year?
Apparently the tests were overdue already. Boeing is not telling everything here.

CFD has improved dramatically so things may change soon, but traditionally the final loads required for the ultimate load tests are only available after test flights.
All tests which clear the aircraft for first flight are purely based on calculated loads, and traditionally those required adjustment through flight testing.

[pittsspecialguy]

First, let me declare my interest. I am an (English) ex-Boeing VP of many years.
Second, let me declare my frustration. The speculative comments on this issue are more akin to the Daily Mail or Sky News, not a supposedly professional site for pilots. I guess many pilots here get frustrated about comments from non-pilots (not to mention wannabe engineers). I wish there were a filtering system to weed out the idiots.
Third, these tests are usually designed precisely to test aircraft to destruction point.
Fouth, regarding secrecy, the original 777 ‘exploding’ wing break test is available online and there is no particular Boeing policy (or indeed US law) on what is or is not published.
Fifth, why does everyone want to be an aerospace engineer? Let the pros do their job and release the aircraft when they are ready. Yes, the MAX has issues but this is not related and to say that the 777 should not be stretched a la 737 (which I agree should have been a new airframe) is frankly laughable.
Fed up with the Boeing bashing. It’s a fine company with fantastic professionals, from the CEO to the guys that clean the floors at Renton or Boeing Field. Do you want Boeing to fail? Or do you all really want to sidestick for the rest of your days?

[CCA]

I believe every aircraft goes through a "High blow" test prior to leaving the hangar it's at 12.1 psid, the first 777 a seal failed and was redesigned, in March of 2006 China Airlines 747-400F blew the nose door open it opened with so much force it went over the limit and smashed the cockpit windows, China Airlines tried and failed to reject the aircraft, Boeing repaired it and delivered it as required, however China Airlines never painted it, it was white, interestingly the pressure wasn't high at the time the door opened. The test is usually done late at night with minimal employees in the hangar, the aircraft is then released to the flight line.

The fatigue airframe was most likely well above normal and abnormal limits so don't think it will cause any delay perhaps a modification to extend the airframe life and a cycle limitation on pre modified aircraft until modified.

[DaveReidUK]

in March of 2006 China Airlines 747-400F blew the nose door open it opened with so much force it went over the limit and smashed the cockpit windows, China Airlines tried and failed to reject the aircraft, Boeing repaired it and delivered it as required, however China Airlines never painted it, it was white

It was eventually painted in CAL livery after about 8 years in service.

[OldLurker]

Fed up with the Boeing bashing. It’s a fine company with fantastic professionals, from the CEO to the guys that clean the floors at Renton or Boeing Field. Do you want Boeing to fail? Or do you all really want to sidestick for the rest of your days?I was right with you up until that last snide sentence.

I'm also fed up with the Airbus bashing. It's no less a fine company than Boeing, and its professionals are no less fantastic than Boeing's, from the CEO to the guys that clean the floors at Toulouse and all the places where Airbuses are made.

[Declaration of non-interest: I have no stake in either Airbus or Boeing.]

[UltraFan]

How different are 777 and 777X fuselages? I take it no substantial changes were done to the new model other than lengthening. Could FAA, who is very "vigilant" of anything Boeing at the moment, dig deeper into this and demand additional testing of the current 777? And, a more pressing question I suppose, can the current 777 be affected?

[Speed of Sound]

And, a more pressing question I suppose, can the current 777 be affected?

Possibly, but that will depend on why this happened which I’m pretty sure Boeing are well on their way to finding out.

[FlightDetent]

Fed up with the Boeing bashing. The pendulum is picking speed, it must be on the downward swing by definition? Welcome to the world of non boeings, yet goings.

[UltraFan]

Fed up with the Boeing bashing. It’s a fine company with fantastic professionals, from the CEO to the guys that clean the floors at Renton or Boeing Field. Do you want Boeing to fail? Or do you all really want to sidestick for the rest of your days?

WHOA! My trolldar just went off.

[sooty655]

...........
Fed up with the Boeing bashing. It’s a fine company with fantastic professionals, from the CEO to the guys that clean the floors at Renton or Boeing Field...............
I'm sure the cleaners and many of the folks above them are "fantastic professionals", but the CEO's public performance these last few months suggests he, at least, may not actually stand up to scrutiny.

[ATC Watcher]

pittsspecialguy (https://www.pprune.org/members/495113-pittsspecialguy) : joined today , 2 posts . one praising BCAL, (agree fully it was a very fine airline), the other saying
I wish there were a filtering system to weed out the idiots..
and
Do you want Boeing to fail? Or do you all really want to sidestick for the rest of your days?
Nice way to start winning friends here , but welcome nevertheless.
And there is nothing wrong with side-sticks, as the first side-stick controlled aircraft was a Boeing one, just flew in it in OSH a few weeks ago. ;)

[Swiss51]

Fed up with the Boeing bashing. ......... Do you want Boeing to fail? Or do you all really want to sidestick for the rest of your days?
No, we want Boeing to produce first class planes that do not fall from the sky, because Boeing did not tell the pilots what it built into them. And we want Boeing to communicate honestly, openly and transparently, what many of us did not feel in the past 9 months. And we want Boeing to return to a safety conscious collaboration mode with the certifiers.

[mrdeux]

Fed up with the Boeing bashing. It’s a fine company with fantastic professionals, from the CEO to the guys that clean the floors at Renton or Boeing Field. Do you want Boeing to fail? Or do you all really want to sidestick for the rest of your days?

As a long time Boeing pilot, who spent his last years flying with a side stick...I really don't care either way.

But, I have a neighbour who was a passenger on a Boeing flight out of Hawaii to NZ which ended because of some rather suss Boeing engineering. He's also an engineer, though not the aviation type, but he was astounded at the design of your cargo door locks.

[lomapaseo]

pittsspecialguy (https://www.pprune.org/members/495113-pittsspecialguy) : joined today , 2 posts . one praising BCAL, (agree fully it was a very fine airline), the other saying
.
and

Nice way to start winning friends here , but welcome nevertheless.
And there is nothing wrong with side-sticks, as the first side-stick controlled aircraft was a Boeing one, just flew in it in OSH a few weeks ago. ;)

Well I'll be glad to welcome him as is

He neither downed Boeing nor Airbus and just told why we need both.

[Winemaker]

How different are 777 and 777X fuselages? I take it no substantial changes were done to the new model other than lengthening. Could FAA, who is very "vigilant" of anything Boeing at the moment, dig deeper into this and demand additional testing of the current 777? And, a more pressing question I suppose, can the current 777 be affected?

The 777 seems to be about the most crash worthy aircraft flying; the little Asiana incident at SFO certainly drove that home.

[Fly Aiprt]

I wish there were a filtering system to weed out the idiots.

"Be careful what you wish for"...;)

[Aihkio]

...
Fifth, why does everyone want to be an aerospace engineer?
...
Some want some don't. So far I haven't seen a rush to the profession. I ended there almost by accident. Bloody dull work at times, like XMM telescope tube with a zero thermal coefficient of expansion ...

[BDAttitude]

First, let me declare my interest. I am an (English) ex-Boeing VP of many years.
...
Fed up with the Boeing bashing. It’s a fine company with fantastic professionals, from the CEO to the guys that clean the floors at Renton or Boeing Field. Do you want Boeing to fail? Or do you all really want to sidestick for the rest of your days?
While I tend to believe that the guys that clean the floors at Renton are fantastic professionals, I am also sure that they are not Boeing employees.
Without the MAX it would have for sure been a side note to special intrest groups. However the MAX crisis is entirely home made and so is the scruntity BA is facing now. Nothing to be frustrated about.
I would hope other entities would learn from that but I'm sceptical.
I'm not sure how the side stick is related to that though. However I am sure that a competitor for AB will be found with or without side stick.

[Smythe]

First, let me declare my interest. I am an (English) ex-Boeing VP of many years.
Second, let me declare my frustration. The speculative comments on this issue are more akin to the Daily Mail or Sky News, not a supposedly professional site for pilots. I guess many pilots here get frustrated about comments from non-pilots (not to mention wannabe engineers). I wish there were a filtering system to weed out the idiots.
Third, these tests are usually designed precisely to test aircraft to destruction point.

Intermediate testing is done to weed out design and materials issues.

This was the FINAL ground test for certification...no learning here, this is to show the ac meets specs. It blew on the blow test and as Boeing stated, they had to stop the test.
The final test for cert is to show that all of the other testing and design assumptions have passed, and the ac is ready to be cert to fly.

This reads that they stopped the test before it was completed, correct?

On the blow test, there are 3 parts..static, working load, and ultimate.

Static tests the normal pressure
Working load tests the assumes highest pressure the fuselage will have ONCE in its service.
Ultimate load tests the working load by 1.5 times.

Boeing claims it had to stop the test...at which point did it stop?
The wording, failed under much higher that normal operations, stil could mean the working load test.

Think about it, if it had failed under ultimate, 1.5...that could be understood, because ultimate at 1.5 is the assumed failure pressure.

Given all of the secrecy, lack of disclosure, and other issues, I tend to believe it failed before working load....

As noted by the "ex-VP" videos are online and the ground testing was usually a media event....this one was closed doors to regulators. (and it failed with all of the regulatory agencies present, )

Time for Boeing to start telling the truth.

[DaveReidUK]

Boeing claims it had to stop the test...at which point did it stop?

Reportedly at 99% of target load.

Which, incidentally, is closer than Airbus got with the A380 wing test before being granted an exemption.

Boeing downplays impact of 777X load test "issue" - FlightGlobal (https://www.flightglobal.com/news/articles/boeing-downplays-impact-of-777x-load-test-issue-460780/)

[Smythe]

Wow, so maybe not really an issue. This is certainly different that a failure on the cabin pressure test which has been reported.

[Speed of Sound]

I assume that if this wasn’t a cargo or cabin door failure as suspected, then Boeing would say that this wasn’t a door failure.

[Less Hair]

According to Boeing's wording it happened during the "final load test" and it broke at 99 percent of whatever the goal was.
So what was the goal? Ultimate load? Limit load plus X? 1,3 max cabin pressure?

[lomapaseo]

Intermediate testing is done to weed out design and materials issues.

This was the FINAL ground test for certification...no learning here, this is to show the ac meets specs. It blew on the blow test and as Boeing stated, they had to stop the test.
The final test for cert is to show that all of the other testing and design assumptions have passed, and the ac is ready to be cert to fly.

This reads that they stopped the test before it was completed, correct?

On the blow test, there are 3 parts..static, working load, and ultimate.

Static tests the normal pressure
Working load tests the assumes highest pressure the fuselage will have ONCE in its service.
Ultimate load tests the working load by 1.5 times.

Boeing claims it had to stop the test...at which point did it stop?
The wording, failed under much higher that normal operations, stil could mean the working load test.

Think about it, if it had failed under ultimate, 1.5...that could be understood, because ultimate at 1.5 is the assumed failure pressure.

Given all of the secrecy, lack of disclosure, and other issues, I tend to believe it failed before working load....

As noted by the "ex-VP" videos are online and the ground testing was usually a media event....this one was closed doors to regulators. (and it failed with all of the regulatory agencies present, )

Time for Boeing to start telling the truth.

To who?

Boeing only needs to report details to the certifying agency and not to the public or its competitors

The customers need assurances that a any process affecting their delivery is being followed.

If adjustments are called for and approved by the FAA then that may be reportable to all.

[Pilot DAR]

To who?

Boeing only needs to report details to the certifying agency and not to the public or its competitors

This.

That fact that some information finds its way in the public realm does not suddenly compel an applicant or authority to explain or justify the outcome of a certification test. I've witnessed many certification tests, both as in interested person, and a delegate of the authority. Some of the tests were not a pass, and some test articles were broken - that's the nature of testing! If a structural element failed at 99% of its predicted ultimate load, hats off to the engineers! A little redesign, with apparently valid design assumptions, and the product should be great. We can hardly have efficient aircraft when the structure has a capacity many times the ultimate load cases - it'll be needlessly heavy.

[tdracer]

This.

That fact that some information finds its way in the public realm does not suddenly compel an applicant or authority to explain or justify the outcome of a certification test. I've witnessed many certification tests, both as in interested person, and a delegate of the authority. Some of the tests were not a pass, and some test articles were broken - that's the nature of testing!
Exactly!!! Too many people on here seem to have forgotten why we test things. Cert test failures are not particularly uncommon (if normally less dramatic than a door blowing out). It got so bad on the 747-400 program that the FAA told Boeing to stop wasting their time - and that they would no longer witness certification flight testing unless Boeing had already performed an 'engineering test' to verify it would pass (doing a verification test before inviting the FAA was often SOP, but the 747-400 got so far behind schedule that they tried cutting out the verification testing and going straight to cert to save time).
I failed my first attempted certification test on the 747-8, even though we had done a verification test previously - the only time in my career I ever failed a cert test. We later determined that the problem was confined to specific OAT temperature band that we had been lucky enough (or unlucky - depending on you point of view) to encounter on the cert test - and it wasn't even my system at fault - it was the FMC. After reading my email to upper management informing them of the test failure, my supervisory pronounced me a 'Master of Understatement' :O
BTW, I flew a commercial flight out of Paine Field yesterday. I counted four completed 777-9X aircraft parked on the flightline (presumably without engines but from the angle I couldn't tell for sure).

[Less Hair]

Yes, still the old approach, What would pilots want to know about MCAS? What about structural integrity?
It should be a valid interest in a forum like this to want to find out more about what has happened aside from that carefully worded to downplay statement.

[EEngr]

Fifth, why does everyone want to be an aerospace engineer? Let the pros do their job and release the aircraft when they are ready. Yes, the MAX has issues but this is not related ....
It's quite possible that the MAX problems may be due in part to process problems inside Boeing. As such, the 777X trouble may very well be related.

Back when I was an 'aerospace engineer' at Boeing, the FAA did look at our processes as well as designs. But that was something Boeing management pushed back against. Perhaps that was a mistake.

[WHBM]

. We can hardly have efficient aircraft when the structure has a capacity many times the ultimate load cases - it'll be needlessly heavy.
Well that's just silly hyperbole. Nobody is proposing that the structures handle 300% ("many times") of requirement. But we hope they will put a little bit of contingency in there. Maybe 110%. But the desperation to get it down to 100.001% of the requirement is what alas leads to this situation, where it fails at the 99% point. Which means, bluntly, it's a fail. And shows among other things overall poor design ability..

Boeing only needs to report details to the certifying agency and not to the public or its competitorsI'm afraid to tell you that if it goes on for much longer like this, where Chicago gives the heave-ho to anyone with a different opinion to theirs, or too much experience (= expensive), or any designer/supplier who is not the low bidder, it's going to get quite soon to the stage where Airbus, and soon the other up-and-coming competitors, are going to have forgotten more about aircraft design than the remaining staffers at Boeing ever knew. So no worries about what the competition might learn there. And very many of us would be really disappointed if that happened.

[david340r]

Well that's just silly hyperbole. Nobody is proposing that the structures handle 300% ("many times") of requirement. But we hope they will put a little bit of contingency in there. Maybe 110%. But the desperation to get it down to 100.001% of the requirement is what alas leads to this situation, where it fails at the 99% point. Which means, bluntly, it's a fail. And shows among other things overall poor design ability..

Not at all, there is still a safety factor, but if you make the safety factor bigger you waste fuel every hour the aircraft is flying. One of the ways the aircraft industry can get away with much smaller safety factors than other industries is the effort that goes into design verification and rigorous ongoing maintenance and inspection. However as an engineer who has used tools such as finite element analysis I find it astonishing that they seem to be able to routinely get within a few percent of the target for such complex structures. Can't help wondering if there is actually a little bit of smoke and mirrors in the details of how they load the structure to help ensure failure occurs at the target load.

[Australopithecus]

From an ignoramus point of view, I'd be astonished if they couldn’t. A seasoned pilot can look at an artist's impression and know if it would work-eventually you get a feel for the hidden structural attributes if you have pondered a few Flight International cutaway diagrams. Eventually even a dumb pilot gets a feel for skin thickness, rib dimensions and spar depths. Modulus, strength, deflections, etc. , Aside from materials, not much is new since the B-47

[cee cee]

Something else I am surprised no one has brought up.

The newer planes are designed to much finer tolerences, requiring precision machines to achieve those tolerences. Obviously the first few built for certification will receive more care to ensure that it is put together properly. But what happens when the planes go into production and become "mass produced"?

We have seen reports of Boeing accepting components for such newer planes that are not made according to specifications. When parts that were supposed to be computer cut were cut by hand. Where holes do not match up and have to be redrilled. Where parts that do not fit are hammered in to make them fit. https://www.sbs.com.au/news/sites/sbs.com.au.news/files/transcripts/381701_dateline_awingandaprayer_transcript.html

A carefully put together aircraft that fails at 99% highest test load may later become a bash-it-in-to-make-it-fit aircraft that fails at a much lower load .

[DType]

MANY years ago, when I was designing inspection measurement equipment, a customer approached us to help him interpret an Airbus drawing. He dared not ask Airbus for clarification, because as a sub contractor he had been supplying the part for year(s) and feared opening an expensive can of worms. But none of my team could understand the drawing either, Airbus seem to have survived that one.

[Aihkio]

Some oddities in drawings nowadays are the result of using CAD tools. Some measurements sometimes are all but undecipherable.

[Bootstrap1]

Has there been any extra information released about this cargo door yet?

Have Boeing confirmed if it was a main cargo door or the bulk cargo door? They have been surpisingly tight lipped about this incident.

I think there is a much bigger problem than just a cargo door.

[lomapaseo]

Has there been any extra information released about this cargo door yet?

Have Boeing confirmed if it was a main cargo door or the bulk cargo door? They have been surpisingly tight lipped about this incident.

I think there is a much bigger problem than just a cargo door.

With such an all encompassing statement without evidence, you are in an excellent position to prove yourself right, no matter how small a newly found problem pops up.

[clearedtocross]

Has there been any extra information released about this cargo door yet?

Have Boeing confirmed if it was a main cargo door or the bulk cargo door? They have been surpisingly tight lipped about this incident.

I think there is a much bigger problem than just a cargo door.

Here is the evidence!
https://simpleflying.com/boeings-777x-ripped-apart/

[golfyankeesierra]

Because the test was within 1% of its target pressure levels, the Seattle Times believes that the aircraft will not have to undergo a retest. While that might sound alarming to some, it’s important to remember that these pressure tests exert immense amounts of stress on the airframes, far more than would normally be encountered in a natural environment.

So, the prototype doesn’t meet the certification criteria. So why not let the certification criteria meet the prototype;)?

[moosepileit]

Add https and www. I can't post urls yet.

seattletimes.com/business/boeing-aerospace/boeing-777xs-fuselage-split-dramatically-during-september-stress-test

[Ian W]

So, the prototype doesn’t meet the certification criteria. So why not let the certification criteria meet the prototype;)?

It is surprisingly similar to the A-380 wing structure test (https://www.flightglobal.com/news/articles/airbus-a380-test-wing-breaks-just-below-ultimate-load-204716/) "The wing of the Airbus A380 static test specimen suffered a structural failure below the ultimate load target during trials in Toulouse earlier this week, but Airbus is confident that it will not need to modify production aircraft." The aircraft was still certified by EASA without repeating the test and you are all happy to fly (on) A-380s.

[golfyankeesierra]

It is surprisingly similar to the A-380 wing structure test (https://www.flightglobal.com/news/articles/airbus-a380-test-wing-breaks-just-below-ultimate-load-204716/) "The wing of the Airbus A380 static test specimen suffered a structural failure below the ultimate load target during trials in Toulouse earlier this week, but Airbus is confident that it will not need to modify production aircraft." The aircraft was still certified by EASA without repeating the test and you are all happy to fly (on) A-380s.
​​​​True, very similar!
Now, what is all the secrecy and fuss about a cargo door?

[Fly Aiprt]

It is surprisingly similar to the A-380 wing structure test (https://www.flightglobal.com/news/articles/airbus-a380-test-wing-breaks-just-below-ultimate-load-204716/) "The wing of the Airbus A380 static test specimen suffered a structural failure below the ultimate load target during trials in Toulouse earlier this week, but Airbus is confident that it will not need to modify production aircraft." The aircraft was still certified by EASA without repeating the test and you are all happy to fly (on) A-380s.

Thanks for the heads up.
To be fair, one must quote the entire paragraph :
However Garcia says that the failure of the wing below the 1.5 target will require “essentially no modifications” to production aircraft: “This static test airframe has the first set of wings built, and we have refined the structural design for subsequent aircraft due to increased weights etc. We will use this calibration of the FEM to prove the adequacy of the structure on production aircraft.”


They say they have "refined" the structure of the production aircraft, utilizing this test on a pre-prod wing to calibrate their calculations.

Nobody will reproach a failed test to Boeing, except maybe this was to be a demonstration that the previous tests had succeeded.
Also it comes at an unfortunate time, with many other quality/engineering issues cropping up.

[Fly Aiprt]

Finally it's a passenger door that blew open, and the fuselage is a write-off...

https://www.seattletimes.com/business/boeing-aerospace/boeing-777xs-fuselage-split-dramatically-during-september-stress-test/

[Dave Therhino]

The fuselage buckled and failed just aft of the wing. The door popping out was secondary.

[atakacs]

To be honest I am surprised this is any worry.

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

[India Four Two]

From the Seattle Times article referred to above:
https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/768x1012/11262019_boeing_130001_768x1012_ffd472c994a77649707b1897c482 ae8fd8db351c.jpg

[Less Hair]

Didn't they want to run it on higher cabin pressure like the 787?

[DaveReidUK]

Didn't they want to run it on higher cabin pressure like the 787?

Yes, max diff on the 777X will be a tad under 1 psi higher than its predecessors to give a 6,000' cabin instead of 8,000'.

[boaclhryul]

99.999% of 150% of the way to SFO

Sounds more like a massive overshoot. What's 4,500 km east of SFO?

[keesje]

Last week FAA declared testing on the 777X would be tougher.
https://seekingalpha.com/news/3520876-faa-will-tougher-boeing-777x-certification-dickson-says

Too late apparently
https://www.theepochtimes.com/foreign-aviation-agencies-to-put-boeings-next-jet-under-increased-scrutiny-reports_3159634.html

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

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

[lomapaseo]

My understanding is that this was not a fit-for-flight test article that failed and only a test used for extrapolation of some proposed features. Surely the final aircraft configuration will meet all the published requirements.applicable to growth airframes validated by many hours of safe-flight experience.

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

[turbidus]

There are now the conspiracy theories floating around, that BA increased the pressure to prevent the hull from buckling during the test.

Looking at the failure, that was quite the explosion?

[turbidus]

My understanding is that this was not a fit-for-flight test article that failed and only a test used for extrapolation of some proposed features. Surely the final aircraft configuration will meet all the published requirements.applicable to growth airframes validated by many hours of safe-flight experience.

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

Aside from the conspiracy theories, the test is a single event test, not a repetitive or cyclical test.

Slowly bringing the ac up to 1.5 loading really doesnt provide a real test of conditions.
I think there is quite a bit of value in repetitive testing to the typical loading, many issues found in the field may have been avoided. having driven through quite a bit of turbulence, I always wonder about the stresses on the airframe.

[Grebe]

My understanding is that this was not a fit-for-flight test article that failed and only a test used for extrapolation of some proposed features. Surely the final aircraft configuration will meet all the published requirements.applicable to growth airframes validated by many hours of safe-flight experience.

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


Geeze- a simple check and knowledge re structural ( static ) test or even videos of 777 test in the mid 90's would make it obvious that the test to 1.5 times design or ' ultimate ' wouild reveal that the article under test was NOT designated or assembled for eventual flight. Airbus does different - but Boeing has never used the structural test article for flight. Usually the structural test article is amoung the first three airframes built. One for structural, one for fatigue test, and one for flight. For example, the first 767 built was for flight test and later sold to United. The second was for static test, the third for fatigue test. By the time of static test, about a half dozen 767 were already in various stages of assembly. :8

[BDAttitude]

From the Seattle Times article referred to above:
https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/768x1012/11262019_boeing_130001_768x1012_ffd472c994a77649707b1897c482 ae8fd8db351c.jpg
Oh boy ... So the door blew out is the new The front fell off

[tdracer]

Aside from the conspiracy theories, the test is a single event test, not a repetitive or cyclical test.

Slowly bringing the ac up to 1.5 loading really doesnt provide a real test of conditions.
I think there is quite a bit of value in repetitive testing to the typical loading, many issues found in the field may have been avoided. having driven through quite a bit of turbulence, I always wonder about the stresses on the airframe.

Apples and Oranges. The test is question is 'ultimate load' - stress to 1.5x the max anticipated load and often to failure even if it's higher than the 1.5x requirement. A different airframe will be used for fatigue life testing, running the airframe through tens of thousands of simulated flight cycles - a test that takes many months to complete. That being said, fatigue life testing is a bit of a black art - accurately simulating actual flight loads is non-trivial.

BTW, for all the Boeing bashing going on, I notice this little tidbit apparently escaped notice:
At the same time, the fuselage was bent downward at the extreme front and aft ends with millions of pounds of force. And the interior of the plane was pressurized beyond normal levels to about 10 pounds per square inch — not typically a requirement for this test, but something Boeing chose to do.
In other words, Boeing had previously done the 1.5x pressurization test - and passed. Then, although it's not a regulatory requirement, they again pressurized the fuselage to 1.5x when they did the wing ultimate load test - when it failed at 99% of target.
Oh, and for all the bitching about 'self certification' - there were six FAA people observing the test when the failure occurred.

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

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/1024x782/63463_1038532900_c6d98b7c23da8ce675f13fece2567158a4953461.jp g

[OldnGrounded]

Oh, and for all the bitching about 'self certification' - there were six FAA people observing the test when the failure occurred.


OK, but that doesn't actually say anything, at all, about the reality of delegated certification authority, which is an undeniable, inarguable reality -- whatever you think of it.

[DaveReidUK]

BTW, for all the Boeing bashing going on, I notice this little tidbit apparently escaped notice:

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

That much was reported soon after the event:

Door blows off Boeing 777X during stress test (https://komonews.com/news/local/door-blows-off-boeing-777x-during-stress-test)

"A door blew off a Boeing 777X as the new plane was undergoing what was supposed to be its final structural inspection by federal regulators.

The test is meant to push the plane beyond its limits. Engineers had the plane pressurized and on the ground. They loaded it up well beyond capacity and bent its wings in an extreme manner, in a way almost certain to never happen in the real world."

Though the combined test was subsequently denied by another poster

Point of clarification here.

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

They were simply doing the cabin pressure test while it was on the stand. (which was prudent, given the results)

who subsequently declined to cite any evidence for that assertion.

[tdracer]

I wonder why Boeing bothered doing a non-FAA test then. And why FAA staff were there. ****s and giggles?

The regulations spell out the minimum requirements - it's always acceptable to do cert tests that exceed those minimum requirements.

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

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

[Pilot DAR]

The reality of delegated authority is that the FAA picks and chooses what is delegated and what it retained, whatever you might think of it in your reality.

Delegation allows the authority to provide a service with more efficient use of authority staff time. If there were no delegation, the taxpayer would be covering the cost of hundreds more staff, both for the volume of certification work, and the in depth knowledge of certain disciplines.

Oh, by the way, 'ever had a pilot flight test? Was it administered by a staff pilot of the authority? Or a delegated examiner? C of A's issued to aircraft - most commonly by a delegate, rather than an authority staff member.

I always invite the authority to witness certification tests I carry out, even if the test is entirely delegated to me. Doing so affords the authority the opportunity to learn, while witnessing testing they otherwise probably could not see first hand. In co witnessing testing, the standards for the test and acceptance, and agreement as to how to disposition unexpected outcomes becomes a joint task, rather than just the delegate - 'builds confidence in the certification system.

Delegation is not perfect, but it's necessary, or our industry would grind to a slow pace.

[Grebe]

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

My confusion/memory re VA001 came from an event in about 1992- . I had kept a copy of the 767 firing order published in 1982 or so, and had dug it out as part of my 1992-93 deposition on some specific tooling and patent issues. AS I recall ( but could be wrong ) the firing order showed VA001 as being ***assigned *** to UAL. The assembly dates were critical, specifically when the tool was first used on a part of the 767 ' production' aircraft versus when the firm that had patented the tool and claimed a design and manufacturing date of the tool as being about 6 months later. Eventually they lost the patent because I was able to show via records accurate to within a few M days the tool setup dates, load dates, etc . I have since thrown away virtually all my notes and depositions. So based on my memory I ** assumed** that UAL had eventually taken delivery. I left the 767 program in 1983 for what was known as WILO ;) and came back to everett on the 777 program about 1993 or so. ;)

MY goof - my point was that that the static test and fatigue test airplanes ( at least at boeing ) are not planned to be put in flyaway condition other than basic structure- and not sold except for scrap or cutaways or whatever.

And FWIW the times article mentioned the loading on the fuselaghe as xx thousand lbs bending downward. Since the it was not pulled down while sitting on the landing gear, a simple force diagram would show that since plane was not moving up or down, somewhere the equal and opposite load up ward had to be available - that upward load was of course the wings bending upward by pulling on a bunch of cables etc :ugh:

[tdracer]

My confusion/memory re VA001 came from an event in about 1992- . I had kept a copy of the 767 firing order published in 1982 or so, and had dug it out as part of my 1992-93 deposition on some specific tooling and patent issues. AS I recall ( but could be wrong ) the firing order showed VA001 as being ***assigned *** to UAL. The assembly dates were critical, specifically when the tool was first used on a part of the 767 ' production' aircraft versus when the firm that had patented the tool and claimed a design and manufacturing date of the tool as being about 6 months later. Eventually they lost the patent because I was able to show via records accurate to within a few M days the tool setup dates, load dates, etc . I have since thrown away virtually all my notes and depositions. So based on my memory I ** assumed** that UAL had eventually taken delivery. I left the 767 program in 1983 for what was known as WILO ;) and came back to everett on the 777 program about 1993 or so. ;)

VA001 was originally intended to go to UAL as you note, but there were some issues with the way it was built that made it unsuitable for commercial service, so Boeing held on to it. Then again, the general view is that Boeing made far more money leasing it to the USAF as the AOA test bed than they would after doing a post-flight test refurbe and delivering it to United.

Regarding the Seattle Times article, I almost laughed when I saw the part about "The test plane is a complete write-off". As if that airframe was ever going to used for much of anything else after the ultimate load test :ugh:

[Fly Aiprt]

Regarding the Seattle Times article, I almost laughed when I saw the part about "The test plane is a complete write-off". As if that airframe was ever going to used for much of anything else after the ultimate load test :ugh:

td,
If it had not failed, it could have been used for other tests, couldn't it ?
Also they were meaning it was destroyed ?
With respect :
Knowledgeable people laugh when journalists use simplified terms for the layman to get the picture.
More knowledgeable people don't laugh nor fuss : they are capable of adapting their level of language to any public.

[Grebe]

fly aiprt said ' If it had not failed, it could have been used for other tests, couldn't it ?
Also they were meaning it was destroyed ?"

even with the failure as described, other smaller tests on certain parts may be done. Other uses can also include minor changes in part configuration found as part of fatigue tests. For but one very old example. The 767 static test failed a bit below the 1.5 mark due to a stringer problem near the tail. So it was removed and parked outside. A year or so later, when some data analysis showed a stress problem with a few fasteners near the aft side of the wing box, the solution was to simply remove the fasteners and cut a " flange" part about 2 inches shorter.By that time a half dozen or more planes had been assembled. In order to determine what special tool might be needed, I simply got permission from engineering to take a mechanic out to the plane, cut off a few collars on the fasteners, and use a small cutoff saw to trim as needed. Then simply write up the process, location, tools needed such that the shop could follow thru on planes that were past that point in assembly. Just but one example of possible use of a failed static test unit.

I'm sure there are many other examples of ' use' of failed static test parts/planes

[Pilot DAR]

If it had not failed, it could have been used for other tests, couldn't it ?

Test articles are subject to "conformity inspections" prior to acceptance for test. It may be the case that a previously tested part is used for a subsequent test, though such reuse would be describe and agreed in the test plan, and the test article would have to be inspected to assure that it was "test worthy" which would equate to airworthy - no defects. Deviations can be allowed, where they would not affect the outcome of the test. It is not in the applicant's interest to test a defective test article, as the test could be a false fail.

Where the test is a flight test, obviously, we intend that the aircraft is returned at least reusable, if not still certifiable. Examples would include over speed or over weight testing in flight, where an inspection of the aircraft following test should verify that the aircraft remains airworthy. Manufacturer's test prototype aircraft are rarely released into service, often because they don't exactly represent the final approved design anyway.

There are times when I'll plan a test to demonstrate compliance to the requirement, then the requirement plus a factor of safety (which may deform and ruin the test article), and then following removal of the test load, a test to destruction, to see how it failed, rather than at what load it failed.

[tdracer]

td,
If it had not failed, it could have been used for other tests, couldn't it ?
Also they were meaning it was destroyed ?


The ultimate load test is always the last planned test for that airframe, since it is often tested to destruction during that test. Further, even if it doesn't fail, the test will take portions of the airframe beyond the plastic deformation stage, so its value for any additional testing is minimal. When they did the 767 ultimate load test ~40 years ago, they planned to test the wings to destruction, but the fuselage failed first.

[568]

The regulations spell out the minimum requirements - it's always acceptable to do cert tests that exceed those minimum requirements.


The reality of delegated authority is that the FAA picks and chooses what is delegated and what it retained, whatever you might think of it in your reality.

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

With respect:
This is a mainly a pilots forum and not so much an "engineering" forum. Your quote relating to the "level of ignorance of certification requirements" may have been construed to mean "engineers have no idea how critical pilots deal with required certifications during line operations", so this may also be true that engineers are also "a disturbing ignorance" to line pilots in general. Pilots fly, engineers do what they do!

[568]

td,
If it had not failed, it could have been used for other tests, couldn't it ?
Also they were meaning it was destroyed ?
With respect :
Knowledgeable people laugh when journalists use simplified terms for the layman to get the picture.
More knowledgeable people don't laugh nor fuss : they are capable of adapting their level of language to any public.

As you know, knowledge is wisdom.
“The only true wisdom is in knowing you know nothing.”

[tdracer]

With respect:
This is a mainly a pilots forum and not so much an "engineering" forum. Your quote relating to the "level of ignorance of certification requirements" may have been construed to mean "engineers have no idea how critical pilots deal with required certifications during line operations", so this may also be true that engineers are also "a disturbing ignorance" to line pilots in general. Pilots fly, engineers do what they do!

Yes, the engineers are by and large somewhat ignorant of what pilots do. However for the most part we know better than to go on a public form and overtly criticize what the pilots are doing based on that ignorance. Many posters - alleged pilots, although in some cases I have my doubts - on this form have no such qualms regarding what the engineers do.

[568]

Yes, the engineers are by and large somewhat ignorant of what pilots do. However for the most part we know better than to go on a public form and overtly criticize what the pilots are doing based on that ignorance. Many posters - alleged pilots, although in some cases I have my doubts - on this form have no such qualms regarding what the engineers do.Indeed that may be true, but I can attest that the converse is also true, outside of public forums.Happy Thanksgiving BTW.

[turbidus]

At the same time, the fuselage was bent downward at the extreme front and aft ends with millions of pounds of force. And the interior of the plane was pressurized beyond normal levels to about 10 pounds per square inch — not typically a requirement for this test, but something Boeing chose to do.In other words, Boeing had previously done the 1.5x pressurization test - and passed. Then, although it's not a regulatory requirement, they again pressurized the fuselage to 1.5x when they did the wing ultimate load test - when it failed at 99% of target. I believe this is where the theories come from...overpressure the hull to prevent buckling...

[OldnGrounded]

Quote:Originally Posted by OldnGrounded https://www.pprune.org/images/buttons/viewpost.gif (https://www.pprune.org/rumours-news/625310-door-blows-out-during-ground-test-boeing-777x-jet-post10628619.html#post10628619)OK, but that doesn't actually say anything, at all, about the reality of delegated certification authority, which is an undeniable, inarguable reality -- whatever you think of it. The reality of delegated authority is that the FAA picks and chooses what is delegated and what it retained, whatever you might think of it in your reality.



Umm . . . I'm not sure how you understood what I wrote to suggest otherwise, but . . . it did not and I do not. I simply said that the fact that FAA personnel were present at the referenced test doesn't mean or indicate anything about delegation to the manufacturer. And it doesn't.

[tdracer]

Umm . . . I'm not sure how you understood what I wrote to suggest otherwise, but . . . it did not and I do not. I simply said that the fact that FAA personnel were present at the referenced test doesn't mean or indicate anything about delegation to the manufacturer. And it doesn't.
Yes, it does. The FAA can choose to witness any cert test they want - even if the test has been delegated. Once the FAA chooses to witness the test, the FAA assumes the responsibility for the acceptability of the test and test results (e.g. pass/fail). Quite common in flight testing - the FAA will often decide they want to ride along to observe even if the test is delegated - once they do that they effectively override the ARs (delegated equivalent of a DER) in determining the acceptability of the testing and the results. And yes, it often goes the other way as well - the FAA retains a flight test, but for some reason decide not to go along on the flight test - automatically delegating the authority to the Boeing ARs witnessing the test.

[OldnGrounded]

Yes, it does. The FAA can choose to witness any cert test they want - even if the test has been delegated. Once the FAA chooses to witness the test, the FAA assumes the responsibility for the acceptability of the test and test results (e.g. pass/fail). Quite common in flight testing - the FAA will often decide they want to ride along to observe even if the test is delegated - once they do that they effectively override the ARs (delegated equivalent of a DER) in determining the acceptability of the testing and the results. And yes, it often goes the other way as well - the FAA retains a flight test, but for some reason decide not to go along on the flight test - automatically delegating the authority to the Boeing ARs witnessing the test.

I'm definitely not making myself sufficiently clear. I understand (really!) about the individual test. I was trying to make the point that what happened at that moment in time isn't particularly relevant to the overall question of delegation.

But we're just arguing past each other, so let's stop.

[FlightlessParrot]

May I ask a question about delegation, relevant to anyone who may travel on a Boeing aircraft.

I have formed the notion, from this discussion, that in the good old days the FAA delegated a lot of responsibility to individual Boeing engineers, who reported to the FAA; the engineers had to manage their dual loyalties, but the FAA was in a position to check that. I think that what has happened is that the engineers now report to Boeing managers, which means that the FAA has delegated responsibility not to engineers whom it can choose, but to the Boeing company.

Is this notion accurate? If so, it's troubling, because individuals have ethical standards, but by modern doctrine, a company's responsibility is to its shareholders, not any ethical ideals.

[esscee]

Very well summed up!

[lomapaseo]

May I ask a question about delegation, relevant to anyone who may travel on a Boeing aircraft.

I have formed the notion, from this discussion, that in the good old days the FAA delegated a lot of responsibility to individual Boeing engineers, who reported to the FAA; the engineers had to manage their dual loyalties, but the FAA was in a position to check that. I think that what has happened is that the engineers now report to Boeing managers, which means that the FAA has delegated responsibility not to engineers whom it can choose, but to the Boeing company.

Is this notion accurate? If so, it's troubling, because individuals have ethical standards, but by modern doctrine, a company's responsibility is to its shareholders, not any ethical ideals.

The delegates always report to their company managers but are still responsible to the FAA for their decisions. No way can a company manager over-rule the delegate. The company delegate does his job of informing his company manager of his interfacing responsibilities with the FAA.

In my view if there was a fault, it was in the decision making based on the information provided to the delegate/FAA and not the chain of command nor a mixed allegiance

[Pilot DAR]

To refine lomapaseo's post a little, the FAA delegates an organizational delegation to the applicant company (Boeing, in this case), who then nominates individuals employed by the company to be delegated persons. The FAA would accept each person to hold a delegation, based upon their merits, and hold that [each] person directly responsible to the FAA. And, the FAA would hold the delegated company also responsible for the overall management of the company's delegation.

In the case of a small problem, the FAA could elect to increase oversight of the delegated work. Surveillance is an FAA responsibility, and its depth and frequency are based upon risk analysis done solely by the FAA. A greater problem could be addressed by reviewing the delegation of the individual, or the company delegation as a whole. For my experience, a delegation holder acts rapidly, and definitively to accept the FAA's desired oversight to prevent the FAA considering removing delegation.

It is a dual loyalty situation, where the delegated person is employed by, and paid by the company, which discharging their their responsibility to the FAA. This is a part fo the reason that the company also holds organizational delegation, so they have something to loose if they appear to influence the work of the delegated person(s).

This is a necessary system, otherwise the FAA would have to employ hundreds more highly qulified people in the certification role, and certification would slow down. It's just a matter of finding the balance of delegation and oversight.

[medod]

Hopefully I have engaged my brain now.

So this *was* the ultimate load test, and the airframe gave way at 99% — in what must be a fairly unusual way? Is the object of this test to test the wings alone or the fuselage and wings as a unit? My introduction to the test was the 777 documentary way back and I’ve always assumed only the wings were being tested.

It must be a safe bet that Boeing didn’t expect the fuselage to fail, but is it possible that the failure is an artefact of the test?

[lomapaseo]

.......

This is a necessary system, otherwise the FAA would have to employ hundreds more highly qulified people in the certification role, and certification would slow down. It's just a matter of finding the balance of delegation and oversight.

and also to add, the FAA is typically outbid by corporate dollars and perks when it comes to "highly qualified" in new technology in aviation. The FAA is thus placed in a "catch-up" mode regarding equivalent means of compliance and certification. For sure the FAA learns a lot in their review of the "proposed means" of compliance but some bad assumptions still get through especially when it comes to assumptions about human error.

[Grebe]

Hopefully I have engaged my brain now.

So this *was* the ultimate load test, and the airframe gave way at 99% — in what must be a fairly unusual way? Is the object of this test to test the wings alone or the fuselage and wings as a unit? My introduction to the test was the 777 documentary way back and I’ve always assumed only the wings were being tested.

It must be a safe bet that Boeing didn’t expect the fuselage to fail, but is it possible that the failure is an artefact of the test?




It is almost impossible to run an ultimate load test on ' only' the wings or 'only' the fuselage except for some ' partial conditions ".. For example over 60 years ago, the 707 fuselage section was immersed in a large water tank and pressurized hundreds- or thousands of times- this the result of Comet disaster re fatigue of window frames. But when it comes to an ultimate test of factory production assembled wings at least part of the fuselage ( above the wingbox ) is involved. -This since to bend the wings up one has to hold something down and if a way was figured out to simply hold the assembled fuselage ONLY above the wing box, it would then call into question about how various loads were distributed, etc. So it is much more realistic ( not discussing regulations for the moment ) to include the whole fuselage (cockpit- above wingbox- fuselage section aft of wingbox - and tail section including aft pressure bulkhead, etc )

Most of the regulations- requirements - were/are the result of the comet disaster- and no doubt further enhanced by the Electra ' whirl mode' disasters. I'm sure a more qualified person than myself can- could expand on my overview above .:oh:

BTW then 767 ultimate load test on wings etc failed due to loads on the aft section and a missing stringer- circumferential near the rear door. result was a approx 10 degree twist of the aft section from normal visible later by the cocked from vertical vertical stabilizer section.

[tdracer]

I have formed the notion, from this discussion, that in the good old days the FAA delegated a lot of responsibility to individual Boeing engineers, who reported to the FAA; the engineers had to manage their dual loyalties, but the FAA was in a position to check that. I think that what has happened is that the engineers now report to Boeing managers, which means that the FAA has delegated responsibility not to engineers whom it can choose, but to the Boeing company.

Is this notion accurate? If so, it's troubling, because individuals have ethical standards, but by modern doctrine, a company's responsibility is to its shareholders, not any ethical ideals.

As part of the transition to becoming an ODA, Boeing put in place a number of protections against "undo pressure" - something that didn't exist previously. This included training of management, and most importantly a clearly defined process for reporting incidents of undo pressure. At least in my experience (nearly 30 years, pretty much evenly split between the old DER system and the delegated AR system), I was far better protected as an AR - literally all I had to do was mention that I felt management was approaching 'undo pressure' and they'd immediately back down. In fact, as an AR, I once had my chief engineer tell an engine company to back off when they started pressuring me to approve a flight test result that I was unhappy with.
OTOH, as a DER I was clearly retaliated against when I made a finding of non-compliance (which resulted in an AD). Not only was I removed from the team working the issue (replaced by a DER who later had his delegation pulled by the FAA due to unethical behavior :rolleyes:), I went from retention 1 (hardest to layoff) to a retention 3 (easiest to layoff) and didn't get a raise for two years (at a time when raises went out every six months). When I mentioned this episode to my FAA mentor, I was told it wasn't their problem - it was an internal Boeing issue :ugh:

ODA isn't perfect, but neither was the old system.

[Pilot DAR]

ODA isn't perfect, but neither was the old system.

There is no perfect system, not in aircraft certification, nor any other discipline in aviation (nor any other industry, for that matter). Events of this past year will serve to remind the delegate community, and those who employ delegates, to discharge the responsibilities with the greatest dedication. I expect that if, in the past, there had been pressures to find compliance from management, management will now be tripping over themselves to demonstrate their patience for the process.

[keesje]

This is a necessary system, otherwise the FAA would have to employ hundreds more highly qulified people in the certification role, and certification would slow down. It's just a matter of finding the balance of delegation and oversight.

I think the resources / costs, time factor has been succesfully used by Boeing to convince and push congress into increasingly demanding further delegation by the FAA to "industry" since the 2011 FAA re-authorization.

At some point in time we need to be strong enough to recognize this delegation and independent oversight has crossed lines (https://www.barrons.com/articles/boeing-737-max-oversight-mcas-safety-global-poanel-jatr-51571064129).

We have to implement corrective actions. At this moment this movement is to driven by non US authorities.https://www.businessinsider.nl/boeing-777x-certification-review-faa-europe-uae-737-max-2019-11?international=true&r=US

[Ian W]

As part of the transition to becoming an ODA, Boeing put in place a number of protections against "undo pressure" - something that didn't exist previously. This included training of management, and most importantly a clearly defined process for reporting incidents of undo pressure. At least in my experience (nearly 30 years, pretty much evenly split between the old DER system and the delegated AR system), I was far better protected as an AR - literally all I had to do was mention that I felt management was approaching 'undo pressure' and they'd immediately back down. In fact, as an AR, I once had my chief engineer tell an engine company to back off when they started pressuring me to approve a flight test result that I was unhappy with.
OTOH, as a DER I was clearly retaliated against when I made a finding of non-compliance (which resulted in an AD). Not only was I removed from the team working the issue (replaced by a DER who later had his delegation pulled by the FAA due to unethical behavior :rolleyes:), I went from retention 1 (hardest to layoff) to a retention 3 (easiest to layoff) and didn't get a raise for two years (at a time when raises went out every six months). When I mentioned this episode to my FAA mentor, I was told it wasn't their problem - it was an internal Boeing issue :ugh:

ODA isn't perfect, but neither was the old system.

The real problem is the management chain. The delegated engineers from the company should have a completely different management chain to the project that they are the delegated certification engineer for. This removes them from the dual pressure of meeting performance targets _and_ the certification targets. Also any manager raising a complaint on a non-compliance finding cannot directly retaliate on 'their' reporting certification engineer, but has to go to another manager in another chain of command to say what their problem is often requiring raising the issue up the project team management chain then across to the certification management and down again. This is normally enough to prevent retaliation or undue pressure to meet performance rather than quality targets.
In most organizations the Quality Assurance system has a completely separate management chain and this can often go up to board level to ensure QA is not put under delivery timescales pressures.

[tdracer]

In most organizations the Quality Assurance system has a completely separate management chain and this can often go up to board level to ensure QA is not put under delivery timescales pressures.

The problem with that is that the DER/AR job is not 'full time' - it's more of a subset to your normal job responsibilities. That's a big part of why the DER/AR system usually works - the DER/AR is very familiar with the system he/she is certifying because it's what they've been working on, and the certification needs are known and implemented into the design early on rather than some last minute bandaids to meet the regs. This is fundamentally different than how the QA system works (on more than one occasion, I had to explain to a QA person what they were looking at and why it was acceptable - they simply don't have detailed system knowledge). The Boeing ODA is already a separate group - with it's own reporting chain (part of the protections put in place for ARs under the ODA), but the ARs still fall under the normal management system for accessing work quality, performance, etc.
Besides, the Boeing management structure is already quite complicated and difficult to understand - adding another management chain might cause it to collapse under it's own weight :rolleyes:

[Ian W]

The problem with that is that the DER/AR job is not 'full time' - it's more of a subset to your normal job responsibilities. That's a big part of why the DER/AR system usually works - the DER/AR is very familiar with the system he/she is certifying because it's what they've been working on, and the certification needs are known and implemented into the design early on rather than some last minute bandaids to meet the regs. This is fundamentally different than how the QA system works (on more than one occasion, I had to explain to a QA person what they were looking at and why it was acceptable - they simply don't have detailed system knowledge). The Boeing ODA is already a separate group - with it's own reporting chain (part of the protections put in place for ARs under the ODA), but the ARs still fall under the normal management system for accessing work quality, performance, etc.
Besides, the Boeing management structure is already quite complicated and difficult to understand - adding another management chain might cause it to collapse under it's own weight :rolleyes:

Yes - it still puts the individual in the difficult position of competing aims - so working in a team trying to meet tight deadlines while also insisting on creating 'delays' for specific testing/regression etc. I have been in the position of being an acceptance manager AND tasked with meeting deliverable times - leads to a lot of cognitive dissonance.

On the organization it becomes 'span of command' and 'unity of control' :rolleyes:

[Grebe]

Yes - it still puts the individual in the difficult position of competing aims - so working in a team trying to meet tight deadlines while also insisting on creating 'delays' for specific testing/regression etc. I have been in the position of being an acceptance manager AND tasked with meeting deliverable times - leads to a lot of cognitive dissonance.

On the organization it becomes 'span of command' and 'unity of control' :rolleyes:
See my post today dec 4 15:21 num 4251 on below thread re seattle times and retirement of Chief engineer Hamilton

MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

[lomapaseo]

When it comes to safety, management shouldn't be making the decisions. The decisions should be made in a process based environment. This way there is less chance of being over-ruled by a tier level. I don't know where the problem was at Boeing in this case. I've worked with John Hamilton and found him to be a straight shooter.

[Pugilistic Animus]

Based on what little we know so far, it's highly unlikely that any of the factors that contributed to the AA or TK accidents were present in this latest event, despite the outwardly similar (npi) outcome.

Agreed, with introduction of dadoe vents there is little chance that a floor collapse will ever happen again.