Certification process for 777X is another hurdle for Boeing

By Scott Hamilton

Jan. 16, 2020, © Leeham News: Certification of the Boeing 777X is far off. The airplane’s first flight hasn’t occurred. There is no date announced when it will,  but sources suggest it could be this month.

Boeing 777-9. Source: Boeing.

The fallout from the 737 MAX crisis and its certification process isn’t fully understood. Neither Boeing nor the Federal Aviation Administration announced what the 777X process will be.

It’s assumed that the discoveries about the MAX certification process will result in a revision to the FAA’s approach to 777X certification.

There are questions circulating in the aviation community whether the FAA will revisit every certification step done so far for the 777X and what it will look like in the future.

A new question arises: will the 777X be certified as a derivative of the 777 Classic—the path Boeing wants. Or will the FAA decide that enough changes are designed into the 777X that it needs an entirely new type certificate?

New vs derivative

Boeing launched the MAX, and the 777X, as mere derivatives of the predecessor airplanes, the 737NG and the 777 Classic.

The 737’s changes focused mainly on new engines, some aerodynamic clean up, some announced flight control changes and, as the world now knows, the MCAS.

By contrast, the 777X has new engines, a new composite wing, commercial aviation’s first folding wingtips, a fuselage stretch and some upgraded systems.

It also has larger passenger windows, similar to the 787. The 777X, however, retains a metal fuselage.

In the wake of the MAX crisis, LNA is told that the overarching question is whether these changes are extensive enough to prompt the FAA to require a new type certificate rather than certifying the X as a derivative.

If the FAA chooses the former, it could add a year or more to the certification process. Boeing sold the X to airlines on a delivery schedule based on an amended type certificate. A new type certificate not only delays the delivery schedule, but adds costs to the airline.

The stress-test blow out of a door on the 777X last year adds another question. The failure reportedly was within 1% of the required safety margin. Boeing initially said this wouldn’t affect the certification timeline. LNA is told, however, that this remains unclear—another potential impact of the MAX crisis.

GE Aviation is certifying the GE9X for the 777X as a new engine, not a derivative of the GE90.

 JATR certification review

A Joint Authorities Technical Review (JATR) board was created to review the MAX certification process. JATR included regulators from 10 authorities. They are the US, European Union, Japan, Brazil, Canada, Australia, Indonesia, Singapore, United Arab Emirates and China.

JATR said its “recommendations raise the foundational issue of whether a process that has historically served the industry well for decades based largely upon compliance needs to be revisited to address not only compliance but also safety. As systems become more complex and may interact in unforeseeable ways, the likelihood increases that regulations and standards will not address every conceivable scenario.

“To the extent they do not address every scenario, compliance with every applicable regulation and

standard does not necessarily ensure safety. Moreover, as systems become more complex, the certification process should ensure that aircraft incorporate fail-safe design principles. These principles prioritize the elimination or mitigation of hazards through design, minimizing reliance on pilot action as primary means of risk mitigation.”

The current FAA certification process is summarized here. The FAA “streamlined” the certification process in 2014, as described here.

Certification timeline

The FAA website last year indicated it takes 3-5 years for certification of a derivative and 5-7 years for a new airplane.

Boeing successfully lobbied Congress to allow the FAA to grant more responsibility for inspections to Boeing through what’s called the ODA program. The FAA retained ultimate approval.

In a change to production Boeing has been working on for years under the code name Black Diamond, Boeing wanted to further compress certification time. The objective was to have only five years from program launch to entry-into-service of a new airplane. Cost reduction as well as streamlining production and certification is part of Black Diamond.

This is why Boeing officials kept saying they could target EIS of the New Midmarket Airplane for 2025 even as program launch kept slipping to the right. (Whether this was realistic was a matter of debate.)

Changed Product Rule

The FAA has a set of regulations called the Changed Product Rule (CPR).

Derivatives by definition change this and that. Under the CPR, the changes are reviewed. Systems and parts of the airplane that are unchanged are not.

JATR concluded in its October 2019 report that in the case of the MAX, the CPR “process lacks an adequate assessment of how proposed design changes integrate with existing systems and the associated impact of this interaction at the aircraft level. A more fulsome assessment process would apply to establishing the certification basis as well as to finding compliance throughout the certification process.”

No announcement has been made by the FAA how this may affect its review and certification of the 777X.

What this means

What does all this mean?

This means there is a great deal of uncertainty surrounding the certification of the 777X.

The 777X already is at least a year behind schedule because of technical design issues with the engines. EIS is now targeted for 2022 vs the original EIS of this year.

Another delay of a year or more due to a new-vs-derivative certification of the aircraft likely places key orders in jeopardy.

Emirates Airline late last year canceled orders for 35 777Xs. Etihad Airways previously canceled orders for 19 of 25 (even though Boeing still lists them on its website). The carrier is understood to want to cancel the remaining six orders.

Passenger traffic for Cathay Pacific Airways of Hong Kong has fallen through the floor in the wake of the civil-political turmoil there. China Southern Airlines, with its hub in nearby Guangzhou, left the SkyTeam Alliance and now code shares with airlines from OneWorld, which Cathay also belongs to. China Southern is expected to divert traffic from Cathy for passengers seeking to enter China. These events may mean Cathy no longer needs its 777X order.

Certification delays could further pressure the viability of the 777X program.


133 Comments on “Certification process for 777X is another hurdle for Boeing

  1. One key point is omitted on the 777x.
    Since all the last Boeing programmes were plagued by delays and misconceptions of some sort (787 batteries, KC46, 737 Max), it is very likely that the 777x will be affected as well by the Boeing “cheap” development culture.

    That would push EIS even more on the right.

    Scott, have you heard anything on the possibility that the GE engines is a cover-up to mask 777x development delays?

    • @Julien: On your last point, I haven’t heard that but I do suspect it.


    • Its typically the slowest animal in the herd that is getting hammered.

      GE may only be a week or two behind the next slowest – which could be (for example) Héroux-Devtek or Meggitt, Collins or Honeywell – but no one outside of Boeing hears of the others, its just who is worst.

      • On the 787 project Boeing used external partner delays or mishaps as shield to hide their own delays. ( rather visible RR and the Trent1000. RR timing had zero impact on 787 timing. ). They also prefer attributing their own failures to partner shortcomings.

  2. Trump and the American people should be grateful to Airbus for agreeing to take up the slack in the LEAP production line otherwise workers would be laid off and GE would be experiencing cash flow problems.

    • Ahh yes, equally grateful they destroyed the American Aircraft building industry?

      I smell a Eurocentric Rat here.

      And GE was already in a financial mess. Same as Boeing, gutting for max bucks vs the future.

      And as I understand it Safran or whoever they are these days build the engine for Airbus and GE the US.

      But yes, we will all get down and pray to Europe, to meet their defense obligations of a minimum 2% per the NATO Charter.

      Or not take gas from Russia.

      • All AB did was develop one narrowbody 30 years ago.Boeing Lockheed and MD did the rest by themselves.

        • Yep, with a huge government bail out that at the Time Lockheed, Douglas and Boeing did not have.

          We are so grateful to have that screwed up by the Europeans.

          Love them allies

          • Only one company in the US is currently producing narrowbody passenger planes, Airbus. They import far more US components into Europe than the other way around.
            The US has done this all by themselves. The vast,bloated and corrupt defence budget provided a huge subsidy, but aerospace companies became addicted to easy money from cost plus contracts and free R&D.
            Your patriotism is being channelled by the Boeing corporation.

  3. How much will EASA be involved?
    I don’t think EASA will accept certification delegation to Boeing.
    If EASA complained about the Changed Product Rule in the JATR report, they might want a closer process.

    • Either Emirates or Lufthansa is launching customers, not a US based airline. That’s how much they are involved.

    • In theory could EASA help FAA with the 737MAX certification work while FAA pushes Boeing to release what EASA needs for their work. In principle could EASA send over +200 certification engineers for a couple of months until EU vacations kick in during July/Aug/Sep to do a good chunk of the Required work/verifications so the 737MAX can start operations worldwide early summer 2020. Congress to find the cash and pay EASA outside FAA budget and Boeing to provide a 737MAX8 for their disposal and shuttling staff back and forth as part of flight tests..

        • No, it’s not. EASA in not to do a FAA job, is to cross check what FAA done. If we mix them both will miss an important safety chain.

    • Leon, don’t forget that the JATR included regulators from around the world and FAA engineers participated and are, presumably, signatories to the final report.

      But I think you’re right to ask what the EASA will do. On one hand they’ve got a pretty damning JATR report that recommends FAA changes its procedures. On the other hand they may be presented with an FAA type certificate issued by FAA having made no changes whatsoever to their procedures. If EASA let that pass and a 777X were to fall out if the sky in European airspace, it would be difficult for the EASA personnel to justify why they let it fly…

      This is the nub of it. The JATR report recommendations are not a joke, they’re serious. If they’re not implemented in full by Boeing and the FAA the personnel of bodies like EASA, CAAC, Transport Canada, etc have no legally defensible basis by which they can justify accepting FAA certifications.

      As it happens I think the personnel of these bodies are already doing Boeing and the FAA a big favour. We know that some of the inadequacies of the MAX are present on the NG (eg the trim wheel stiffness). We know that there’s been persistent FOD problems in brand new 787s. We know that some aspects of the certification process examined by JATR were in place for 787’s certification. A fussy regulator might object to these problems and ground those aircraft too, just in case there’s anything else they’ve not been told about.

  4. I understand the wings to be new, the fuselage structures are remodelled, the engines are new, the systems are new but heavily borrowed from the 787 with only the aircraft skin being substantially the same as the plane it replaces. It was always a stretch to certify the 777x as a derivative. Even if the FAA accept it as such, I doubt the EASA etc will do so, in the light of the MCAS certification issues. They will want a first principles certification.

    If so, I suspect the delay will be longer than the delta between a new and derivative plane certification. Boeing will need to redo certification it has already done on the new basis.

    • Is this substantially different to the changes made when designing the 737NG ?

      • I think the 777x probably is a bigger change than Classic 737 to 737NG, but maybe not original 737 to MAX.

        A f0llow up on my earlier point. Recertification doesn’t just mean ticking more boxes. Components that meet one certification standard won’t necessarily meet another and will need to be redesigned.

      • 777X is said to retain the center wing box only.
        gear track gets wider.
        will the FBW system get a drastic makeover?
        737NG kept the center wing box and the basic “carrying” structure of the wing. reprofile, extentions …
        gear track stayed the same.

  5. The fuselage inner diameter has been changed too, through some significant adaptations, resulting in an extra four inches of cabin width. So you might say that it had a new fuselage too.

    • Fuselage outer width is the same, just the internal ring beams are slightly less wide where the passenger sits. Its a gradual thinning which widens out again at the floor beams.

  6. The tail is differently sized also. https://airwaysmag.com/wp-content/uploads/2017/06/Screen-Shot-2017-06-07-at-3.04.42-AM-1024×768.png

    The fuslage has different lenght, load patterns, door locations, window structure. The fuselage rupture during testing can have focussed attention on the certification strategy there.

    Changed Product Rules (e.g., 14 CFR §§ 21.19 & 21.101) and associated guidance (e.g., Advisory Circular 21.101-1B and FAA Orders 8110.4C and 8110.48A) should be revised to require a top-down approach whereby every change is evaluated from an integrated whole aircraft system perspective.

    That means no patching while using reliability numbers of the previous design, when that is not representative.

    • Is it possible that the ‘beam flattening’ required to create the additional internal space could have had anything to do with the door rupturing? Probably not, but the twisting momentum must have increased with flattened circular ribs – no?

      • Reports were that the fuselage longitudinally buckled in the test, which was the expected mode of failure under the applied loads. The buckling plus internal pressurization caused the fuselage split and consequent door release.

        The test was not necessarily to failure, just to the ultimate load, but they didn’t quite make it (within 1%). They may be allowed to demonstrate upgrades to reinforcement and not have to test again.

        • The A380 had a wing fail at 147% as I recall.

          As it failed where they said it would, they were allowed to beef it up and not re-test.

          I think that is common sense approach. If it blew someplace unexpected, then no.

    • keesje – are your ‘fuselage rupture,’ which I’ve seen reported as such elsewhere, and Scott’s ‘stress-test blow out of a door’ one and the same failure (as I suspect) or two different events? I believe I saw a photo of a large split in the fuselage skin, which I wouldn’t expect to be excused on the ground of its happening very close to the load threshold. Nor do I recall seeing chapter and verse reported in, say, AvWeek. I think we should be told.

      • Yes, same event. The fuselage was energized by pressurization, as well as by deformation to ultimate load, so at failure there was a release of that energy (elastic strain plus explosive decompression). The buckle occurred at the bottom, then ripped up the side and took out the door support, releasing the door.

    • Relating to horizontal stability and redundancy,
      ‘third actuator for stab’
      ’60” tip extension per side of horizontal stab’

  7. I’m fully in favour of more rigorous certification and the end of absurdly stretched grandfathering rights (including right now on the X) but it also seems unreasonable of a government to move the goalposts after the product has been built based on the government’s OK. I think it would be entirely reasonable of Boeing shareholders to seek financial redress from the FAA (and Boeing of course) if this happens.

    • It is an interesting Point you make. There is probably no easy answer but it could be pointed out that Boeing, as they keep on stating, has been designing and manufacturing aircraft for decades. Based on that, they have managed to convince Congress and the FAA that they can carry a significant, major portion of the responsibility in certifying their products.

      Now they have been exposed as not really being in control of their processes and one could almost go so far as saying, not really being honest or forthright with the degree of their changes on the MAX series.

      I think it would be, at the very least, irresponsible of the FAA not to exert a greater degree of oversight and control over the certifcation process of the MAX and of any current programmes until the issues that have recently cropped up have been solved. Possibly this should be a new, permanent process as it seems to be pretty obvious to most that self regulating has not been a very successful, as far as safety is concerned, method.

      Launching a lawsuit against the FAA to get redress for Boeing’s own methods and actions? I don’t see that working out well at all.

      • I wouldn’t suggest against the FAA alone. If Boeing is shown to have acted in a way that harms its shareholders then I would hope the shareholders would act against Boeing. I’m simply indicating that I disklike any governmental retrospective goalpost movement.

        • If the shareholders “act” against the company they are simply acting against themselves, unless you are talking about one subset of shareholders (those who bought between date x and y for example).

          Whether shareholders can act against the personal assets/income of (overcompensated) executives individually or as a group (which is what you would really like to do) I don’t know, but I doubt it.

          • The corporation is financed also by debt, not simply by investors (ie shareholders), so the two are not identical.

            As for which party might have a case and against which other party then yes, class of shares held and dates held would be relevant.

            As for clawback against senior executives, given that much of their remuneration is through shares in the corporation, if they are shown to have acted irresponsibly toward the corporation and/or other shareholders then I would hope there is a way to clawback.

      • Lots of cert requirement are designed to provide for a benign crash behavior. without destructive crashed compromised measures do not get exposed.

        In scope:
        The 737 has a knack to break just ahead and just behind the wingbox. .. killing passengers.

    • Perhaps I should also note that this isn’t a game. But if you wish to continue the analogy, Boeing has bent the rules to such a degree that those rules need to be changed. That they and their shareholders, who are pretty aware of Boeing’s behaviour, would complain about these rule changes is a pretty specious complaint.

      • ( in US context: ) Boeing’s predicament demands changing the rules to make the changes apply to the whole market to avoid penalizing Boeing and allow another round of “gaming the system”.

        From a nonpartisan position it would be fully sufficient to make Boeing actually toe the line.

    • Woody,

      Perhaps @Scott could clarify, but I wouldn’t expect the government/regulators to state that they will allow grandfathering rights before an aircraft was built.

      As I understand it, the airframers build aircraft with grandfathering in mind, in the hope that the regulators are convinced when it comes to certification.

      Just because the tail has been allowed to wag the dog in the past does not necessarily mean that will be the case in the future. Unless a very good legal team had been able to get a watertight agreement down on paper !

      I’m not sure caveat emptor exactly applies, but it’s for the shareholders of the company to decide if, and how much they want to invest in a company. The shareholders trust that the board run the company effectively, if they don’t that’s entirely between the shareholders, and the company.

      I may be wrong, but I wouldn’t expect the shareholders to have any case for claiming financial redress from the FAA or Boeing.

      • My expectation would be the opposite. Boeing is clearly woven very closely to the FAA and I don’t see any way that disucssion of what would be acceptable grandfathering didn’t happen between multiple parties during the definition stage. Even if the relationship was a properly professional arms length one, if I was a customer, employee or shareholder I would find it unacceptable for an OEM to not have these discussions (as seemed to be the case in items here during the C Series dark days). I’m not talking manipulation, simply an open dialogue so that the basis for moving ahead is clear, to the benefit of all.

        I agree it may be difficult or impossible for shareholders (or suppliers for that matter) to seek financial redress and am aware of the concept of Sovereign Immunity in the US legal system. But I still think it would be entirely reasonable of them to seek it (ie discuss with lawyers what actions may be available) if the goalposts are moved retrospectively. I’m sure top legal minds have already considered the issue

      • “As I understand it, the airframers build aircraft with grandfathering in mind ..”

        I continue to expect someone providing a good example of “grandfathering overstretch” beyond the examples Boeing. provides.

        independent of what Airbus would like to do:
        The FAA had a peeled eye on anything that could be leveraged to disadvantage Airbus.
        This created just another vector improving Airbus products. ( While Boeing could push sub par stuff on the market.)

        As can be watched today “protection” in a way carries its own death penalty.

    • Don’t forget the foreign regulators, they may be forcing the FAA’s hand. Up to now if the FAA accepted certification as a derivative it was a near certainty EASA and others would follow the FAA lead. That may no longer be true. A certification of the 777x as a derivative is useless if not accepted globally.

      • Yep, a complicated puzzle to solve for all who messed up. I include at least EASA in this as a) I don’t see how there can’t have been discussions/leakage from FAA people to EASA people through friendships, drinks at meetings etc, about the negative developments within the FAA and b) as I posted months back, EASA themselves have been found to be suffering ‘conflicts of interest’ and my guess is they’d like to avoid the glare.

        • I agree with you second point but how would you expect EASA to act upon FAA negligence prior to the crashes? This would have been considered a treacherous act by a legislature far less punchy than MAGA Trump

        • I’ve never met Americans fraternizing in the domain of discontent if at all. Force of tribalism “best of the best” is too big. Russians or Brits. sure.

    • The full cert requirements then also applies to the A320NEO and the A330NEO.

      I am fine with that as long as its applied equally.

      Not that big a change? Well then we are exempt.

      Who defines bit a change.

      The MAX was far less a change (more NEO) than the 747-8 or the 777. T

      • “The full cert requirements then also applies to the A320NEO and the A330NEO.”

        Just for example: I haven’t heard that in A320neo or A330neo they changed fuselage ribs to carbon fiber. Have you?

        Or they augmented 15% windows. Have you?

        You are trying make equal what is not equal.

        • TW’s point is valid, there seems to be no clear definition of a new design vs a grandfathered one. Regs are too gamable.

        • I disagree.

          A320 clearly added a stability issue.

          I call this cherry picking, highly selective as to what is a change and what is not.

          A350-1000 had huge changes and it was ok?

          Fool yourself but you sure are not fooling me.

          • In principle you are correct about change in itself. At the same time both NEO projects required or implemented a level of change of anything near either the MAX or the X. The stability issue is an interesting one and how it plays out will be instructive

          • Not big changes for the A350-1000, unless you think changing from a 2 axle to 3 axle undercarriage is a big deal.
            Plus were 5 frames forward and rear, lengthened trailing edges on the wings, same fan size but bigger core on XWB Trent. Some more structural composites and other overall strengthening
            777X has more changes on empennage than were done for whole 350K

          • A350 was signni changes, more so than 737.

            But 737MAX is an issue when A350/A330NEO/A320NEO is not?

            I smell a rat.

            No question 777 and 747 were massive changes and justify a cetetgory of different.

            Here are the changes:

            “The A350-1000 has an 11-frame stretch over the −900 and a slightly larger wing than the −800/900 models with trailing-edge extension increasing its area by 4 percent. This will extend the high-lift devices and the ailerons, making the chord bigger by around 400 mm, optimizing flap lift performance as well as cruise performance.[196] The main landing gear is a 6-wheel bogie instead of a 4-wheel bogie, put in a one frame longer bay.”

            And a new engine.

            So tell me that is not massive!

            I call BS

            But you can’t argue the MAX vs the others

          • @TransWorld

            A350 is a complete new design, a design with a future strech in the mind. Because it is how planes grew last decades.

            Eg. Does A350 has new ribs? No.
            Eg. Does A350 has bigger windows? No.

            I think you are envy that A350 is more modern design then 777 if you comparing a strech like A350-1000 to a new version like 777x, and you’re trying to make it equal.

          • A320 is a FBW platform from day #1. So, any stability issues are as always dealt within the flight rule parameters. 737 MAX OTOH, is a mechanical flight system with a bolt on augmentation system that works as a FBW but is not a FBW. AB can increase the size of the engines as much as they want without full recertification as long as the rest of the plane stays as-is.

            New engine, new flight rule parameters, test these, test the integration with the rest of the plane, off you go. Nothing new.

            A350 is a clean sheet design with extensibility in mind. They didn’t have to do anything not thought before when they were introducing A350-1000.

            So, it’s apples to oranges comparison. Sorry.

      • The difference, I think, is that the 777x is almost entirely a new plane, while the A320neo, the A330neo and the 737Max are mostly not, even if they had some substantial changes. It’s a question of where you draw the line.

        The other thing is that the MCAS issue happened. Regulators will get pickier about grandfathering designs, regardless of the manufacturer. Boeing is unlucky maybe, that the music stopped just as they were trying push through an egregious amount of grandfathered certification. I am sure in hindsight they would have gone for a more conservative development for the 777x

      • To apply your view:
        you have a “caught thief” and a “non-thief”.
        you demand that both go to prison for the same duration.
        “Just to be fair” :-)) You’ve definitely misunderstood the concept of “fair”.

  8. When I see an aircraft that, apart from the outer dimensions of it’s fuselage, and it’s family name, is substantially different to the original aircraft that it is based on, I call that aircraft a duck.

    Apologies to James Whitcomb Riley !

    I would have quoted Monty Python, but it would be too easy to make links with aircraft, and wood.

    I suspect that the elephant has been spotted, and both the FAA, EASA, and the other regulators will be looking at certification with far more vigour. Expect certification of the 777X to be more like certification of a new aircraft.

  9. Mr. Hamilton, I believe your deadline for this article is wrong. You have January 16, 2022. is this deliberate or did you mean to write January 16, 2020?

  10. Every so often the effectiveness of moving Boeing headquarters to Chicago is revisited. I think it is time to revisit that again. I think the general belief is – It didn’t hurt, but it didn’t help. It has never seemed like a good idea to me to move the headquarters away from the largest business unit and center of excellence. The Boeing crisis recovery process is in the very early stages. I wonder if moving headquarters back to Seattle should be a part of that process. I think there is no question that top leaders need to be closer to the crisis recovery of Commercial Airplanes business unit.

  11. Hiding, decepting, strongarming, mocking it’s regulator … it’s FAA’s time to review and withdraw Boeing’s ODA …

    • 340-300 to A340-600?

      Any shortcuts would have been cut short by the FAA.
      you can bet on that.

  12. A comprehensive certification process, will warrant a safer aircraft.
    That will save money, and time, in the long run.
    I think, these are all good news, for Boeing and its Customers.

  13. … Just a random question… Would the 777X also need a MCAS type system to counter undesired aerodynamics effects of the new engines?

    • Well it depends on if you think the MAX was an evil menace and akin to the Wright Flyer or a miner piece of Software gone Lethal (Think HAL and 2001 a Space Odyssey)

      The 777 is an FBW aircrat per the A320/A330/A350/A380

      When they found the same issue on the A320, they just tweaked the software (same as Boeing) to smooth out the issue.

      Any handling changes on the 777 will be done the same way, they will tweak the software so it handles like a 777-previous.

      • HAL in 2001 going mad is actually a rather good parallel to the MAX. HAL went “mad” because he had competing directives. Killing the humans on the expedition resolved the issue. ( his rational solution.)

    • BernardP – perhaps it will depend to what extent a similar pattern of behavior could occur in remotely similar circumstances? Absent any very similar – or, indeed, different – aero effects (which surely are linked to the particular combination of thrust, alpha, and c.g., et cetera?) there might yet be found a different set of considerations, but for the moment we should give Boeing the benefit of the doubt until test results confirm 777X behavior characteristics (which can be addressed as necessary and presumably as agreed). Recent industry experience has sharrpened minds; no doubt hearts will follow.

  14. These delays have another complication. The aviation landscape changes quickly. As an example, QF ordered 787s to fly from Aus secondary cities to varios EU capitals. By the time they arrived EK had eaten their market. QF cancelled 35 or so aircraft and suffered massive losses thanks to the delay.

    How many of LH or IAG’s planned 779 routes are under 4000 mile? A321 is busy breaking the market down, doing just what BA claimed the 787 was going to do. QR & others are likely to see 3x321s as more usefull than 1x777X. The 777X market is shrinking as we watch, same as the A380 market did during AB’s 2 year design fiasco.

  15. “The stress-test blow out of a door on the 777X last year adds another question. ”

    They seem to have gamed the testing environment by increasing blow up pressure in the fuselage to push back buckling i the fuselage surface.

    This seems to have created some kind of “blowback” !?

    • And TFH strikes again.

      Frankly its purely a stupid remark as this is an intensively documented and recorded and observed test.

      More anti Boeing and US for Anti sake than any aircraft discussion.

      No more relevance than the A380 failed wing test. Great common sense call to not force an expensive and wasted repeat. They knew the issue, where it would happen and dealt with it.

      • Again you took care to make a point.
        But it does not prensent as the statement you think you made. 🙂

    • Uwe, the pressurization could be viewed either way. In a non-deformed cylinder, it strengthens the cylinder and resists deformation, as you say.

      However once there is forced deformation (downwards in this case), it resists failure on the compression side (top) and assists failure on the tension side (bottom). The bottom is where it failed, which would be as expected.

      I think Boing was doing a combined test with pressurization present. Possibly the pressure could delay the onset of deformation, but since this was an ultimate load test, deformation was expected.

      • thin walled structures ( like fuselages ) tend to show buckling in the compression area as prominent failure.
        stiffening via internal pressurization reduces not only the compression but also moves the buckling failure further out. ( see Euler failures, friend of mine wrote his thesis on silo structures buckling :-).
        I am rather certain that Boeing again went for gaming the certification environment to find the right place between Scylla ( stress failure ) and Charybdis ( buckling failure in compression ).
        Without over pressurization the destructive test failure would have happened earlier.

        • Uwe, you are right that the compressive side was on the fuselage bottom. I thought they applied the load in the middle but I checked and they applied it on the ends.

          The silo case is an axial load in gravity compression. Pressure resists the load so delays deformation, and any deformation represents buckling for that case (inelastic with no restoring force).

          The case here is an elastic bending load, with only the pressure load acting axially in tension. In that case pressure can either assist or resist the bending, depending on Poisson’s ratio for the material. A ratio below 0.5 will assist, a ratio above 0.5 will resist. A value of 0.5 is neutral. Aluminum has a value of 0.33.

          They applied 3 million pounds of force to the airframe. 500,000 up on each wing plus 500,000 down at each end, with 500,000 internal pressure force pushing out axially at each end (slightly more than 10 psi).

          So like the silo, the pressure load would resist the onset of deformation, but once elastic deformation occurs, Poisson’s ratio would slightly favor further bending.

          I looked at the regulations for the ultimate load test, pressurization is not required, but it is required for the flight and landing load tests. So I think the idea is to make sure the combined loads don’t create a coupled weakness or failure.

          • I don’t think that “Poisson’s ratio” has any place here.
            Essentially you have a thin walled tube.
            The test beyond other effects bends this tube.
            unpressurized the neutral zone is ~~in the plane along the middle of the tube.
            upper lobe should be in tension lower lobe in compression. If you pressurize the tube the neutral plane moves down, the compression zone shrinks, forces there go lower danger of buckling is reduced. for the same stress you usually need more structure to avoid buckling than to avoid a tension failure.

          • Uwe, the effect of Poisson’s ratio is that it favors strain in the lateral direction, which favors bending of the tube if a bending force is present. Bending compresses the internal side and tensions the external side. This is why when pipes burst due to internal pressure, they bend and the rupture occurs on the outward side. So the pressure contributes to the bending load, once bending is present. In this case the bend is introduced by the test.

            For higher values of Poisson’s ratio, strain is favored in the circumferential direction, so tends to straighten and strengthen the tube. This is used in the so-called burst-proof garden hoses. Composite materials are used to get the desired ratio.

            Another example was found in the buckling of drill pipe in the Deepwater Horizon incident, which caused the blowout preventer to fail. It was not recognized that internal pressure would contribute to the buckling force. All that was needed for failure was a bending force, which was provided by turbulence in the high-velocity flow rushing by the external pipe surface.

            So a heavy free-hanging pipe still buckled. Subsequent calculations showed the internal pressure contribution plus the pressure on the end of the open pipe, were enough to buckle. The friction & bending loads of the rushing fluid were the final elements leading to failure.

            Based on this, it was realized that most blowout preventers could not stop a blowout after flow had begun. The Obama administration then changed the rules to require backflow preventers to shear the drill pipe under any position or flow conditions. The Trump administration has since reversed that, claiming the cost is too high.

          • @rob:
            “Poisson’s ratio” is about _solids_ changing their volume under stress/tension deformation.

          • Uwe, in this case Poisson’s ratio applies to the solid material of the fuselage walls. It favors either lateral or circumferential strain of the pipe walls, which determines the effect on the pipe under pressure.

            The compressive buckling effect of internal pressure on a closed pipe is described here:


            The similar case for the unconstrained open drill pipe (as for the Deepwater Horizon incident) is given here:


            In both cases the effect of internal pressure is to enhance the buckling of the pipe. Note also the dependence on an initiating bending force for both cases.

  16. Not sure if 777X has similar issue with having sufficient space to fit the engine at the right spot under its wings

    The 777 Classic already has Staff Protection (one single quick nose-down cmd only), Over-speed Protection and Under-speed protection in its autopilot. my buddy designed it new on that plane

  17. If they have to redo all certification, could it be the chance to add carbon fiber fuselage panels a la a350 and change the game? Maybe change anything else they were cautious of and make a true fully new aircraft?

    • You are talking about an all new aircraft design.

      That is totally like not going to happen.

      The A350 is not an A330 with composite panels.

      Its from the frame up composite deigned frame and panels.

      • It’s basically saying that they have no method to safely certify an aircraft.

        Time to close the whole thing down, just give up?

    • I’ve been scanning the report, reading the different paragraphs, the wording, values, assumptions, pride and descriptions of all the good work done by Boeing, FAA and US Aerospace in general.


      These are soldiers, former colleagues, defending their nations industry and institutions. They will be praised by their friends at Boeing, Congresss and FAA, DoT for their hard work.

    • They would say that at FAA wouldnt they.
      Independent experts might disagree

      • Well that statement is in a way correct.

        Interfacing and activity distribution between Boeing and FAA the it was : A knew type cert would not have changed the compromised processes.
        ergo: statement is ok. it leaves out the unsuitability for the task set of how the certification process worked.

    • I think the report correctly points out that the MAX problems stemmed from new developments that were newly certified as amended, rather than from legacy components from earlier certification. So the changes were the issue, and the committee then also made recommendations for improving the change review process.

      The claims that amended certifications were the problem, were never really very evidence-based, they stemmed more from the view that it represented cheating or gaming the system, and allowed older technology to persist and compete with newer technology.

      It hasn’t really been shown that safety is compromised, because all safety issues take the form of AD’s which then become applicable to all aircraft, new and old. They become required alongside the amended certification. So nothing is really left out or omitted from those concerns.

      • That’s not how grandfathering works. They clearly avoid new requirements by various means , usually as waivers , or because of expense or other reasons.

        • Duke, waivers are a separate process from amended certification. Perhaps greater scrutiny is needed there as well.

          The committee looked at whether a new type certification would have improved safety of the MAX as opposed to the amended certification. The word waiver doesn’t appear in their report.

          • Problem is how the certification process is conduct per pure facede as MAX when FAA was thinking a boxes as per Boeing’s staff said without checking or per job well done as 777.

            Grandfathering isn’t so bad if it’s rationally done. EASA said that they wouldn’t allowed a planemaker to self check, self certify a new system. FAA allowed.

    • None of this smells correct.

      For the first part, surely any new TC would require the sort of assessment ‘in the round’ (rather than in isolation) that anecdotely is suggested as causing delays in getting MAX2 ironed out?

      For the second part, are they really implying that updated TC requirements since the 1960s are nothing at all to do with safety?

      Have I misread or misunderstood something?

      • Woody, safety changes for a given type are usually done in AD’s. Those are then integrated into all aircraft. So the type does move forward over time with safety concerns, including amended types.

        The current scrutiny of the MAX is unprecedented, we really haven’t been here before. So we will have to see the extent of the changes that come out as AD’s for the MAX, beyond those we know of for MCAS and FCC. That will be the only way we have to evaluate the process.

        • I’m not questioning the ADs. I’m questioinng the apparent assertion that the MAX, grandfathered way back to 1960s certification standards, can be considered as safe (certification wise, not statistics of actual accident rates wise) as an airliner certified to more newer, more stringent standards. If the more stringent/demanding certification standards did not arise from a safety ojective then what? And if they did arise from a safety objective, how can a MAX certified to 1960s standard ever be considered as safe as one certified to 2010s standard?

          • The first fallacy of this argument is that the MAX design has not changed or been responsive to safety concerns since the 1960’s. That is simply not true, any safety concerns that have been found have been addressed and incorporated into the design.

            The second fallacy is that something designed recently is inherently safer than something designed in the past. Again this is not true. If you have a new design, it might have newer components but they are also unproven. If you have an older design, it might lack the newer components but those it does have are proven.

            Each iteration introduces new problems while some of the old benefits are left behind. That’s just progress and how things move forward, but it’s a trade-off as well. Today’s unproven technology becomes tomorrow’s proven technology, with learning and adjustment.

            Certification rules move forward with an eye on improvement and changing technology. If an improvement can reasonably be incorporated into an existing design, then it is, and that is true also for the 737. Or if there is a compelling safety argument, then it also is incorporated, and that may not wait for certification rules, it might be done with AD instead. But not every rule change needs to be retroactive to every aircraft in existence.

            If you believe there are specific features of the MAX that are unsafe, and have evidence to show they are, then that should be brought forward for consideration. But the argument “it’s an old design” by itself does not imply this.

          • Well, Rob you seem to not have understood good design practice.

            In the long run you do not fiddle with details in a progression of steps to avoid problems.

            You abstract out knowledge gained and start from new dropping old chaff on the way.
            This obviously demands that you have wider scoped understanding of what you are doing.

            With vertically educated cubicle minds this is difficult. They’ll dig in on small details and lose the general picture.

  18. Is there a list of components that would fail a new certification compared to the grandfathered certification? Unless safety standards have changed, a new certification should yield the same result. If the standard has changed, then obviously it reduces safety.
    So, what parts would require a change on the MAX, 777x or the 320neo? Is there anything really critical among those items?

    • That the problem with looking at seperate systems. They might be as good / better than the previuos ones & if you downplay / don’t requalify the interface to reduce cost and time you and up killing people. That’s what the JATR (including FAA) report is about.

      With a new TC all those interfaces are automatically included because required from a top down design perspective. Even if they aren’t there you have to prove / demonstrate that. And all the latest requirements / lessons learned from previous similar designs are adopted.

      The committee should not have analysed if everybody sticked to the rules, but where the rules were coming from, when & why they were adjusted, changed or exempted.

      Why the h.ll the 777-9 is certified as a 777 when everything has been significantly changed in safety related areas.

      They aren’t blin(ed), are they?


      • Keesje, that was one of the recommendations of the committee, that additional attention be paid to the interface, systems integration, and human factors elements of amended types. So I think they understand.

        The basic conclusion was that amended types are not less safe, are not involved in more incidents, and that safety has been increasing for both types over time.

        The #1 factor in flight safety is the ability of the operator to support a comprehensive safety management system or program. Improvements there have been a major contributor to the increase in safety. The manufacturer or type certification is still important, but is not the only factor.

        • “reforms must be adopted to help our extremely safe aviation system become even better at identifying and mitigating risk.”

          “the committee’s report finds the FAA’s ODA process, broadly speaking, “appropriate and effective”. It urges lawmakers to “recognise” that the ODA process has allowed “innovation to thrive”.

          “The committee found that the FAA and Boeing did develop a “comprehensive certification plan” for the 737 Max. It says the FAA, through use of ODAs, “acted appropriately in determining its level of involvement for each element of the certification plan”.

          Some committee. Reassuring.

          EASA can learn a lot here.

          • Keesje, the discussion of ODA was separate from that of amended type. The type statements were pretty solid as there is no evidence of past resolved issues from earlier types recurring, or that might have been avoided by a new type.

            The ODA statements are less rooted in evidence. Boeing has been fined numerous times in the last several years for failing to report things to the FAA, which is one of the express purposes of ODA. So the evidence goes against the notion that ODA requires no reform.

            Also although the committee described conducting widely ranging interviews, including Airbus, there was no interview with EASA, which holds the primary countering view.

            I would have preferred some consideration and evaluation of the EASA position. If ODA is better than DER, let’s hear why. That was pretty much ignored. So the conclusions seem incompletely founded.

    • It’s all about Boeing’s self certification nonsense. The KNKT report provided a hazard calculation which used a not normal way which is not allowed. So to certificate everything again on the 777x will of course provide different results.

      Also it can be expected with Boeing’s practise of hiding that things were changed without notifying the FAA. Same as it ever was.

      If I were a regulator I would check all certification documents and I’m sure I would find mistakes. Jedi mind tricking was just Boeing’s routine. Can’t be an independent software audit was never provided for the 777.

      By time we might find out when this tricking started. The tricks on the MAX just started to be uncovered, much more should come, which in turn will make a deeper checking necessary.

      • I agree with you. To give just one example of many. We were told that a problem with MCAS would present itself as runaway trim stabiliser. What it tested even though the flight test programme was 2000 hours? No.

        Boeing told the FAA. The FAA ticked the box. No questions asked. In that situation it doesn’t matter whether it is a new or amended type certificate.

        The FAA were not told the true nature of the forward lift produced by the nacelles and they were not told the true nature of Boeing’s solution. Instead, Boeing said they wanted to tweak the speed trim system to make a MAX, from the pilot’s perspective, behave like an NG. The FAA swallowed it hook, line and sinker. Game over.

        • Well there is a whole industry out there that knows differently.

          Not sure what you are going to do with the MAX if flying again.

          Throw yourself on the floor and scream, no, no, no, no, they just can’t do that! Mommy, they aren’t doing what I told them.

          Sorry dear, you arn’t in charge and won’t be for some time if ever.

          • Don’t you know you have already lost.

            I remember you saying it will fly in April, May, June, July, August… and so on.

            In other words, you have been throwing your toys out the pram for longer than I can remember.

            If the MAX does come back, it won’t be given an A+, it will be given a D-. It will be worthless. So don’t cheer too much if it does come back. The regulators will do it through gritted teeth.

            As far as I’m concerned, job done. Boeing are not above the law.

            Have a nice day!

          • “”Well there is a whole industry out there that knows differently””

            Seems the industry is learning now how to make monitors work.

  19. At one time, GE didn’t want the GE9X to be subject to the 150 hr triple redline test, claiming a different test would be better. I wonder if the regulators have told GE to do the 150 hr test. Perhaps they tried to do the test and it failed. For whatever reason the GE9X is still going backwards.

  20. Boeing is doomed. Amazon should take it private, fire all senior leadership, bring HQ back from Chicago and fast track NMA and a 737 replacement.

  21. I really don’t think the issue is grandfathering per se. I think it the use of grandfathering to circumvent regulations. Regulations do make clear that if a part is changed, the effect – the hazard – of changing the part must be thoroughly accessed.

    The JATR report centred on this. Just read the letter that accompanies the report. It is brutal. It tears Boeing apart, all the way to the bone.

    Boeing walked all over the regulations. The regulators know it. The JATR report cannot be any more clear.

    With regard to the 777X. Can it be subject to an amended type certificate. My answer is no.

    To give one reason of many reasons. The fuselage blowout. Clearly the bigger windows, the carving out of the frames and the longer fuselage have changed the structural integrity of the fuselage. Change doesn’t mean it’s wrong. It does mean the 777X needs a full fatigue test that will last many years.

    When it’s necessary to do a full fatigue test lasting many years, you might as well give it a new type certificate, for that’s the world of a new type certificate.

    With regard to the MAX. The same applies. Clearly the use of the stabiliser is causing a complete shift in aerodynamic configuration. That requires a complete reevaluation of stability. Again the world of a new type certificate.

    • Philip, the fuselage blowout has been discussed several times on Leeham. The fuselage buckled during the test at 99% of ultimate load, which was many millions of pounds force. The buckling released a huge amount of energy, in terms of elastic strain plus explosive decompression.

      So the buckle started a tear that ripped up the side of the fuselage and past the door support, which then released the door.

      The test was witnessed by 6 FAA inspectors. As with Airbus structures that also failed just before ultimate load, I’m sure they’ll make an adjustment and show that it’s compliant.

      • Please read my post. I said there has been a change in structural integrity. I did not say structural integrity failed. After all the blowout didn’t happen with the orginal 777. The change needs to be tested.

        Boeing cannot do those kind of changes without redoing the tests. Neither can Airbus. But Airbus don’t argue. Airbus just get on with it.

        You clearly are of the view that you are the Shirriff. If you think it’s been discussed it’s been discussed. And whatever answer you give is the right answer.

        You really do need to read what Steve said about you.

      • To spell it out to you, as the 777X fuselage did not behave in the same manner as it’s predecessor, Boeing can’t claim grandfather rights. They have to do the tests.

        It costs money. So Boeing argue. Airbus don’t argue. Airbus just get on with it.

        • Philip, the A380 wing failed at 145% of the design limit. Airbus argued successfully not to repeat the test, as was appropriate. They also used the test to tweak their finite element modeling, and adjust the design slightly to show compliance using simulation, with no actual retest.

          In the original 777 ultimate test, they reached 154% of the design limit, but the aluminum wings failed before the aluminum fuselage.

          In the 777x ultimate test, they reached 148% of the design limit and the aluminum fuselage failed before the composite wings. They will use the same approach as Airbus to show compliance.

          • Clearly you still haven’t read my post.

            I’m not saying Boeing need to repeat the pressure test. I am saying that because of the blowout it needs s full fatigue test.

            With regard to the A380. As it was new, a full fatigue test was necessary regardless of the maximum force test.

          • Philip, it does get a full fatigue test. I didn’t mention that in the last post because you complain that I’m the Sheriff when I correct you.

            If you review the 777X development, several test articles were built, for both static and fatigue testing. There are stories on-line with photos of the fatigue test rig and the test article being positioned last May.

          • Rob,

            Pleased to here it. So why the pickle fork problem. A full fatigue test would have found it well be before it was found elsewhere!

            Let’s hope the 777X is put through all the tests necessary and the results reported accurately.

          • “They will use the same approach as Airbus to show compliance”

            ? Rob, are you serious ? Those are two totally different aircraft, authorities, OE’s, failure modes and certification approaches / processes!

            I surely hope Boeing and FAA approach the fuselage explosion like this!

          • Fatigue testing demonstrates that the design is adequate for expected average loading cycles during aircraft life. However the actual fatigue load on individual airframes can vary greatly during service. This is why regulators require regular inspection and do not rely solely on fatigue estimates or testing or design.

            This also is why the problems are found in only some of the aircraft inspected, and are not universal. And why rulemaking has evolved from safety-by-retirement, to safety-by-design, to safety-by-inspection, to now limit-of-validity.

            Fatigue cracking is possible for any aircraft. A380, A320, A321 are examples of Airbus products that have also had directives to address cracking. That does not make them unsafe, if the problem is found and repaired early. Designs are adequate for small cracks if growth is arrested. Remediation for fatigue is not unusual.

          • Keesje, the failure was the same in A380 wing and 777x fuselage, by buckling. The A380 wing was not also pressurized so there was no explosive decompression or split, as there was in the 777x fuselage. The split also released the door.

            The energy released in the decompression was about 93 MJ (69 kPa to zero in a pressure vessel of 1,779 cubic meters). If released over 1 second, that would be a power of 93 MW. That’s more than enough to cause a split.

            The same methods should work to address the 777x buckling as were used for the A380. But we’ll see what the FAA says.

  22. There seems [a lot] more new than old in & on the X. The extra large engines, weight distribution, stresses, drag, larger windows cut from same fuselage skins/stresses, electrics, wings/attachment/folds, landing gear weights etc.

    I work in software dev. You change 1 thing and it can cause a cascade of unexpected events on things elsewhere you never thought about.

    It seems very odd than even before the max fiasco (different drag/weight due to engines) the X was a tube that got the Frankenstein treatment to make it work… Like the tanker, the max (look at it… It’s horrendous… Bolt-on-Betty) etc.

    I doubt it can be certified as a derivative, not should it.

    • I don’t think it matters any more. Following the MAX there will be a lot of careful looking into interfaces and differences. So much has changed in rhis aircraft that it will effectively be a new certification now.

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