Looking beyond MAX

Nov. 25, 2019, © Leeham News: Boeing still doesn’t have a timeline for recertification of the 737 MAX and the Federal Aviation Administration isn’t going to be rushed, but aerospace analysts are increasingly looking beyond the grounding at a normalized Boeing.

It will be well into 2021 before Boeing clears the inventory of MAXes.

Nevertheless, analysts see the proverbial light at the end of the tunnel, hoping that it isn’t an oncoming train.

Boeing quietly rolled out the 737-10 MAX last week in an employee-only event. The 10 MAX is the last of the long line of 737s that began with the -100 model in 1967. It had a capacity for 110 passengers. The 10 MAX can seat 220 passengers. Boeing photo.

Recent events

The orders and commitments at the Dubai Air Show for 60 MAXes are signals that the MAX crisis may be coming to an end.

The low-key roll-out last week of the 737-10 MAX—the largest and last of the long line of 737s—would have been a big event were it not for the crisis. No media was invited; only Boeing employees were present, understandable under the circumstances.

First delivery was originally planned for 2020. It’s unclear what the impact of the MAX crisis will be on this timeline.

A recommendation by a manager of Transport Canada that MCAS should be removed before the MAX is returned to service may throw a kink into the process. Transport Canada hasn’t acted on the recommendation and it carries no official weight with the FAA. At least one official within the FAA agrees.

The story was first reported by The New York Times.

Looking at 2020

With the resumption of MAX deliveries in 2020, Boeing’s cash flow—which is the key measure by which aerospace analysts look at the company—will resume with it.

Bernstein Research, always one of the most favorable toward Boeing, wrote in a note today:

After management discussions, Dubai orders, and more MAX detail, we keep our Outperform rating and $433 target price. We lower our 2020 FCF to $26.39 (from $26.99) and raise our 2021 FCF to $35.42 (from $34.99). Changes are mainly due to slightly later MAX deliveries.

Positive factors affecting 2020 FCF include: Cash on delivery for stored MAX’s and planned ramp to 57/month by the end of 2020 and likely more 2020 orders than in 2019. Our model slightly moves back MAX deliveries. Negative factors for 2020 FCF include: Lack of progress payments in 2020 for airplanes that already received them in 2019, but will not be delivered until 2020-21, rate cut on the 787 and delay in 777X deliveries. These changes are already in our model, except those tied to our slower 737MAX delivery outlook.

Emphasis is in Bernstein’s note.

Melius Research

2021 Outlook

Bernstein assumes the stored MAXes will be delivered at a rate of 25/mo, beginning initially with 10 next month (which may be optimistic). At this rate, Bernstein sees the final stored delivery by September 2021. Any delay in FAA authority to resume deliveries, of course, pushes this timeline to the right.

Bernstein notes the stored delivery rates may vary, perhaps significantly, depending on when customers want to take delivery due to seasonality and other factors.

Interestingly, Bernstein sees the production rate returning to 52/mo by July 2020 and increasing to 57 by October 2020 but delivery rate of newly produced airplanes lagging throughout the remainder of 2020 and all of 2021.

Melius forecasts free cash flow of $26.70 per share in 2021.

2022 normalized year

Melius sees a stock target price of $520 per share in 2022, or 16 times free cash flow.

222 Comments on “Looking beyond MAX

  1. I am afraid the light at the end of the tunnel is indeed an oncoming train.

    Follows an excerpt from a recent article by Dominic Gates in The Seattle Times that is anything but reassuring:

    “Even if Marko’s dissent gains no support and the regulatory authorities proceed with the software upgrade rather than its removal, at this late juncture his message indicates a surprising lack of confidence in Boeing’s fix.”


    • Interesting Seattle Times article. I presume as more test pilots, airline pilots and flight engineers fly the MAX with MCAS.2 this issue will be addressed. If Boeing could just move away from making the MAX handle like an NG, then however the plane is made to handle will be a new standard for the plane. But because of costs and commitments, they are not going down that path,…..yet.

      • @sam walker: “If Boeing could just move away from making the MAX handle like an NG, then however the plane is made to handle will be a new standard for the plane.”

        The standards are established by the FAA, not Boeing. Here is another excerpt from the same article that explains what I mean by that:

        “Marko’s suggestion of dumping the flight-control system instead of fixing it is startling because various investigative reports and briefings suggest that without MCAS, the MAX may not meet FAA certification requirements.”

        • So let me get this straight, what you are saying is that MCAS.2 must be made to work, and is a requirement of the FAA, because they think it is needed to be airworthy?

          • That’s correct.

            But to make things clearer MCAS is the solution offered by Boeing in order to meet the FAA requirement of a certain behaviour of the aircraft under somme circumstances that could be encountered by the pilots during any given flight.

            So the FAA does not impose MCAS as such but only imposes rules that need to be satisfied in order to get certification, whatever means are taken to meet the requirements.

          • I believe Norman has it nailed.

            As MCAS is the only viable solution to that issue, MCAS it seems to be.

            My take is get rid of it.

            Training looks to be mandatory anyway so from Boeing perspective that is a mute issue (or could be)

            How the regulators feel? How open to interpretation this is?

            Some areas that they could not do anything about they simply live with and have training ensure it does not get there.

            As your reaction to stall is nose down anyway, that has always been my take, get rid of it.

            But a Bureaucracy once it has a bee in its bonnet hates to change.

            It would be interesting if like Microsoft in Europe, they get a different version in Canada that we do in the US (bless the EU and its protections)

          • Norman, and the result all this is the probability that with a disabled MCAS the aerodynamics are unacceptable. Does that promote MCAS 2 from “nice to have” up to “essential for flight at all times”? If so then Boeing’s implementation is woefully inadequate.

            I fear that somewhere down the line some crew will get caught out by a failed MCAS and exposed to the true underlying aerodynamic behaviour, and will crash. I Also dislike that the new limit functions introduced into MCAS are not implemented in triplicate, like any other safety critical system would.

          • I’ll expand on my previous comment. Apparently one of the features of new MCAS is to activate “only once per high AoA event”. Let’s break that down into the required functionality.

            1) detect start of high AoA event
            2) activate MCAS, activation count -> 1
            3) detect end of high AoA event
            4) reset MCAS activation count to zero; permits reactivation.

            How the hell are they supposed to do 1 and 3? To me they’re complex functions requiring interpretation of a lot of air, controls and maybe inertial data to get it right. And if any of that goes wrong, eg an AoA sensor flutters (due to damage?) who’s to say that functions 1 and 3 won’t go badly wrong?

            I think Boeing are trying to pull the wool over a lot of people’s eyes with this one. Duplicate redundancy may be enough for MCAS to decide to act when it is appropriate to do so. The trouble is that the important part, ie reigning in MCAS and stopping it acting when it shouldn’t, stopping it killing the souls on board, is probably something that requires triplicate redundancy and triplicate independent implementations (you know, same functions implemented by 3 different teams).

            And they’re not building that. From what they’ve been saying they’re installing 2 copies of the same implementation.

          • @ Mathew: “Duplicate redundancy may be enough for MCAS to decide to act when it is appropriate to do so”. Not only Duplicate but triplicate function is inadequate in my view. Multiple simultaneous Alpha sensor failures have occurred on Airbus aircraft and lead to harrowing near misses and at least loss of one aircraft and aircraft. The fact that Airbus has done nothing is indication that they too suffer from the same “resting on success” mentality as Boeing. At least 4 alpha sensors are required, ideally two vane types and two pressure null seeking types that have a different failure mode, backed up by traditional leading edge vane Switches to cross check the alpha sensors. Likewise for the pitot-static “Prandle” tubes. All need a backup to synthetic air data via AiIDRU and GPS. It’s ridiculously easy to implement but I suspect Airbus is awaiting MCAS like disaster before it implants synthetic air data. Their flawed systems already lead to the loss of AF447.

          • GPS backed Air Data Input like Boeing uses.

            I’d look into the background of the relevant certification
            trail to see if this is not another Boeing/FAA “advantaged certification environment” thing.

            I can think of a number of issues that make it “duh, obvious, simple but wrong.
            What is EASA’s position on “synthetic airdata” ?

          • Transport Canada can decide by themselves I think of ordering a disconnect MCAS and enforce simulator training for Canadian registrered 737MAX’s, but it might be hard under an amended Type Certificate. Other CAA’s might then elect to do the same.

          • @William, indeed.

            I note that the F117 had 4-channel redundancy for its famously hard-working flight control system.

            Okay, the F117 has ludicrous native aerodynamics taking a whole heap of “augmentation” (fine result too by all accounts), but someone at Lockheed decided it was necessary to do that 4 channel FCS in an aircraft with only one person on board. And they gave them an ejector seat too, just in case, and generally they reckoned they weren’t going to get shot at either.

            In comparison, mere dual redundancy looking after the wellbeing of 100+ souls on a 737MAX seems churlish in the extreme, especially when MCAS is primed to push the nose down in a life threatening way if something somewhere else goes wrong.

            Airbus have been a whole lot more diligent about their business, but what you relate just goes to show that designers really, really cannot be too careful about their designs.

          • @Uwe, regarding synthetic air data derived from GPS, well I can imagine on the good day that that would work quite well.

            However, I’d hate to think about the consequences if a maliciously minded person onboard had a GPS jammer with them, or that one was transmitting from the ground close to the approach flightpath, or if the GPS constellation was misconfigured, etc.

            There’s a ton of assurance one would have to add to the GPS satellite system itself, and the aircraft’s onboard GPS receiver(s), before it could be pronounced “reliable” (i.e. able to work, and able to say when it wasn’t working).

          • There are two separate issues:
            Issue I is maintaining the type rating of the B737 MAX so that a B737 NG pilot can fly it. For that the MAX needs to same handling characteristics as the NG.
            Issue 2 is meeting the static stability and progressive ‘feel’ requirements of FAR Part 25 which require a certain amount of progressive stick force specified in pounds.
            “Grandfathering” isn’t always a benefit. Boeing may meet the stick force and handling requirements of FAR 25 but may be too different from the NG to share the type rating.

          • @Matthew. Synthetic Air Data derived from GPS (and a combination Glonass and Galileo) would be run through an inertial navigation system first. The accelerometers would maintain a 3 dimensional velocity reading for the aircraft with a velocity drift of about one knot per hour. (That would be the drift rate of a moderate INS). So any loss of GPS signal would have noteffect on INS data for at least 1 hour. Traditional Military technology of the 1950s/60s would use LORAN or TACAN to measure the position of the aircraft and use this to update the INS position. Doppler would update the speed and side drift. If the aircraft was over hostile territory and navigation beacons being jammed the aircraft would use its INS with the actual velocity being maintained to a high accuracy via doppler radar.

        • That’s the crux of the real issue, isn’t it? MCAS is needed to pass FAA certification of this Franken-jet, right? The jet can’t fly well (if at all) under all circumstances with these big new engines on this old-design of an airframe without a software fix, right? This is an attempt at a fly-by-wire fix for big engines this airframe was never designed to use, right? The whole thing is a kludge for Boeing to try to keep up with the A320 rather than give up market share or devote 10 years of development time to a new airframe, right? And let’s be frank. A jet that’s about 50% larger in passenger capacity and with completely different engines is not really the same plane that was certified to fly in, what, ‘67, is it? It’s sort of an airframe from 50 years ago, with engines never designed for it, using software to (hopefully) make it fly, practically designed on the assembly line with 2 catastrophic accidents under its wings, right? It’s a Frankenstein monster of a jet, right?

          I feel like we need a show of hands to see who would actually be willing to fly in this thing.

          Please note, I am not connected with airlines or airplane manufacturers in any way. I am just an occasional passenger and sometimes commercial air traveler.

          • Brain:

            I quit my job last year (note quit not retired)

            My mother lives in Washington Stae.

            Alaska Airlines flys all 737 and will have MAX

            I will fly the MAX with no qualms.

            My wife flew an A320 that had a key bug in the software that could crash the aircraft. They had like 5 years to correct it.

            The fix, a Pilot response (where have we heard that before)

            Frankly I would love to get in a MAX simulator with MCAS 1.0 loaded and beat it.

            I had solid training in flying the aircraft and if you do the rest takes care of itself.

          • I don’t see the MAX as the Franklin-jet and here is why: the B737 was signed to be short on wheel and to be a small regional aircraft for small regional airport. It even had its own folding stairs. The B737 200 was flying with grace and elegance close to the one of the eagle.

            But Boeing decided to plays with the genetic of the B737 stretching its fuselage, putting bigger engines and adding some computer on it even if it is not made for that, they also stretched its legs for the MAX10. To me the result is a Big fat transgenic turkey that have the brain of an earth worm. When it ties to take off, its butt tend to pass infant of its nose. Forget about the eagle’s grace.

          • I think that the answer, albeit from my perspective is, how and why was Boeing allowed to “grandfather” all of these additions for an archaic airframe? Perhaps I am closing the barn door after the horses are long gone, but 347 lives lost trusting this plane???? Some thing stinks here, and all of the touchy feely crap ala Boeing doesn’t make me want to flay a Boeing product.

          • Boeing isnt selling planes to passengers, its selling them to airlines who are high sophisticated and technically aware customers ( OK exclude LionAir from that) who use them to make money.
            Lots of planes especially from the 50s and early 60s were ‘Frankenstein’ even from the beginning , Comet come to mind, even the early 707 had plenty of kludges and yes it too was re-engined with larger diameter JT3D turbofans. Check into the early technical and aerodynamic changes made to get to the 707-320Bs everyone remembers.

          • ” So the FAA does not impose MCAS as such but only imposes rules that need to be satisfied in order to get certification, whatever means are taken to meet the requirements”

            The problem is to meet a 50 year old FAA requirement re a linear yoke force increase as plane approaches an impending stall at the VERY rare edge of the flight envelope- Boeing used a brute force method with no backup and no mention.

          • = = = this Franken-jet = = =

            Personally I don’t see that the use of this type of construction based on an adjective selected to generate a negative emotion combined with a synonym for airplane selected to cleverly complement the attack adjective adds much to the discussion, but that’s just me.

            Both Boeing’s customers and Boeing selected the option of further enhancing the 737NG over a clean-sheet redesign. There were reasons for making that decision – some good, some less good, and a few that in hindsight were bad. But it was a rational decision by knowledgeable people not a hasty sewing together of parts from a graveyard (“Franken”).

          • Not so much a ‘franken’ as a ‘kranken’ or hospital plane

          • @sPh
            November 25, 2019

            = = = this Franken-jet = = =

            Personally I don’t see that the use of this type of construction based on an adjective selected to generate a negative emotion combined with a synonym for airplane selected to cleverly complement the attack adjective adds much to the discussion, but that’s just me. {/cite}

            In a societal context that loves to ballast any statement with polarizing semantics your statement is about as bigotted as can be.

            ( same for any stateement that insinuate any Boeing hazing as unfair retribution where reverse hazing never needed any factual foundation.)

          • @Dukeofurl
            November 25, 2019
            “Boeing isnt selling planes to passengers, its selling them to airlines who ………”

            planes full of kludges back then…

            The accident/incident numbers in that era reflect that.
            We have made (quite a bit of) progress in the mean time.
            But Boeing’s brilliance regressed that to before Comet1 time rates afaics.
            AND not for not knowing any better but for base and absolutely frivolous reasons.

          • The term Franken is a pathetic throw back to Airbus PR on a 767 derivative.

            Of which Airbus morphed the A300 into not one but three downstream versions (two major variants of the A330 and the A340 with a plethora of -xxx) using the same now denigrated grandfather clause.

            Based on that sloppy terminology, the A330 is a Frankengod .

            Aerodynamically the changes on the 737MAX are minter compared to the ones done on the A330 (or 767)

            And still the A330 (sans dumb pilots) has a good record as does the 767,.

            Using push button terms just diminishes the throwee and totally is lame in lack of originality.

    • It seems to me that given the very large number of people around the world that are looking at MAX certification, there is bound to be some dissent. So I would expect some of the dissenters to speak up, as Marko has. That’s a consequence of the all-inclusive process the FAA has created, in order to help restore trust.

      We’ll have to see how much traction the dissenting view attracts within the majority. My reading of what Marko said was that we start fresh from the NG controls, with MCAS off the table this time. He wasn’t suggesting any other solution, just saying he disagrees with MCAS as the solution.

      That makes it hard to evaluate, he is essentially recommending a future but presently unknown solution. The uncertainty associated with that seems rather large.

    • What I didn’t see in what I read is what he proposes to meet the regulation that MCAS was intended to meet. (Am MCAS like approach is not the only way of course.)

      Sounded like he doesn’t the regulation is needed. Certainly things like MCAS complicate the airplane and the pilots’ life.

      • Basically he’s saying; get rid of MCAS and work on hardware changes to solve the actual problem caused by the engine placement.
        Obviously that results in the MAX being more different from the NG.

        Allegedly Boeing would get in to trouble regarding contract clauses (with buyers) that specify pilots don’t need extra training to go from NG to MAX.

  2. Hopefully 737 deliveries and introduction of the -10 will be back on schedule soon, stabilizing the market place.

    KLM gets the honour of taking the last 737NG : https://pbs.twimg.com/media/EKGKvcfVAAARP1X.jpg

    On looking beyond MAX, there’s always analysts to be found, confirming what we love to hear. Cherry picking & generalizing positives while by-passing / “already known” negatives. Or the other way around for a competitor.

    It’s not so much about lying, it’s about selecting news to steer public perception.

    Hardly Hidden stock boosters do their work:



    I think Leeham news gets kicked from both sides for being pre-occupied. That’s were you want to be long term. Feared & respected. Not an embedded news forwarder of one of the huge, impressive, lavish OE’s.


    • Keesje:

      Thank you for the link, I was curious where the NG was at.

      I don’t kick Leeham , but then I like facts and they present facts along with their assessment of them.

      We may not agree on assessment but the fact per Bjorn etc are solid.

      And clearly they are successfully in business and offer the only real forum for this sort of discussion.

      I would love to see the paywall articles but that is their bread and butter and understand why they need to do it.

    • 7542 for KLM ?
      The last line number for NG seems to be 7597 for Skymark
      7542 wasnt on the list Ive seen , was it way out of sequence as 7541 was delivered around 6 months ago

      • @Duke: 7542 was a fuselage that was rejected by Boeing for QC issues. This replacement fuselage was assigned the same line number; it’s out of sequence in this case.

    • keesje – isn’t this ‘last’ NG a replacement airframe for one that was DBR during assembly? Does anyone out there have details of what happened and the subsequent destiny of the damaged airframe? Was/wre any element/s saved?

  3. BA are fortunate that there is no competition capable of taking up the slack. Saw an article taday stating leasers are furious as BA’s new MAX orders are equal to 275k month, leasers have been getting 350k, no wonder BA are seeing MAX movement, at zero margin, maybe? Apparently BA are also squeezing them for progess payments on undeliverable aircraft. This wili end up being reflected in future pricing of BA products, and, to a lesser extent, AB’S. It might also lead to a degree of reluctance amongst customers to get involved with BGS. Hard to get away from them once you’ve shut down your own MRO.

    • Unless contractually agreed, I don’t visualize BA having the remotest chance of “Squeezing” Leasing Companies/Airlines for any Progress Payment on Undelivered Aircrafts, on the contrary BA is liable for any Loss Of Income incurred by these companies.
      BA committed High Treason to the Aviation market by Marketing and Selling a Defective B737 MAX knowingly, but still took its clients for a Ride, while it lasted, consequently could be found Penally liable.
      As for the B737 MAX 10 Propaganda Stunt, “Employees Only”, hope it is not with another Dummy aircraft, as was the case with the unveiling of the B787 in a Grandiose Public ceremony in July 2007.

      • While I think there is a serious criminal element in Boeing and the MAX, I don’t think High Treason applies.

        As Norm notes, Boeing is obligated to supply viable aircraft, not store ones.

        So their intake is zero until they get it certified.

        As it stands the MAX is not certified and all the clauses in their protect the buyers from that condition.

        And Boeing indeed will be paying compensation or more likely wavering payments at various levels to the extend of the buyers losses.

      • According to Airinsight some leasers are indeed bound by contracts to keep paying progress payments. I guess the lawyers didn’t see this one coming. So BA are just enforcing the contracts, but for the leasers it’s money out at the wrong time, and I guess it will come back to haunt BA at some time.

        • I asm willing to bet a pay check that the lawyers can break

          Clause 1 with Clause 2/3, i.e.

          Progress payments are due at stages of completion (1)

          No payment is required if delivery is 6 month late. (2)

          Various penalizes per Clause (3) are incurred for late delivery.

          Legally I would guess removal of certification of ht aircraft trumps all pay clauses.

          And that assumes Boeing is not making adjustments already.

          • And airlines can opt to buy Airbus so yes they will get their protective clauses in.

            Its not a matter of who has the sharpest lawyers, the agreements have a long known history that any decent lawyer can boilerplate in.

            Regardless Boeing has a serious interest to avoid more bad publicity.

      • It was news when Ryanair stated they will stop progress payments on aircraft not yet delivered…

        So it must be ongoing for others.

        • Going public or not may be the only difference here?
          Ryan Air has an additional reason for holding onto their money from the MAX200 having run into evacuation certification issues.

  4. I doubt that BA will finish delivering the stored aircraft before 2022. Firstly, operators will be more interested in using their retrained crews, as training looks like being the bortleneck, to reactivate their existing MAX fleets. From AA/SW/US scheds we know this will take until March, best case. They won’t want new aircraft any earlier, although I expect BA will get some PR deliveries done. Many airlines have leased aircraft for up to a year, looks a bit like they are covered for the summer. Winter scheds aren’t so tight, airlines won’t necesarily be in a hurry for dels next winter. Then, remember, airlines can only accept aircraft at a certain rate. BA can’t just say, ‘here are your 50 aircraft.’ Finally, I agree BA will ramp up production as fast as they can to restore stock market confidence. Does anybody see airlines taking 75-80 airframes a month? So BA will have 450+ stored aircraft by March, deliver 20 stored aircraft a month, last of the stored aircraft gets delivered early 2022, baring further delays. Normal won’t happen until we see how FAA et al deal with certification issues in the future.

  5. Keesje “Hopefully 737 deliveries and introduction of the -10 will be back on schedule soon, stabilizing the market place.”

    Boeing will have to get the MCAS or what ever else to be certified first, then they will have to certify the MAX7, the MAX200 then the MAX10. There is also the 777x the be certified and it will probably not be on time.

    Then there are the NG’s pickle forks to be replaced, and all of those storage MAX to get back in the air. If the FAA decide to follow the NTSB recommandation, 6 000 NG’s will have to get their nacelles to be replaced.

    The KC-46 still as quality issues, and the spacecraft is having problems.

    I don’t see how Boeing is going to make it in time with the MAX10

    • I don’t think they will be “replacing” nacelles, but instead retrofitting existing nacelles with extended containment rings.

      in theory, they just need to remove the portion of the nacelle forward of the fan and install a remanufactured section with an integrated containment structure

      • This was my take on it as well. The sheared blade may have bounced around and exited the nacelle at a location that wasn’t reinforced. So the reinforced containment needs to be extended.

        It’s an extremely high-energy event that is difficult to test or simulate. If a blade ricochets, I’d guess you want it ejected out the front or back (depending on blade location) and away from the engine, wing, and airframe.

        • Away from the engine?! It is a part of the engine. I don’t think it is physically possible for it to hit the engine, it would have to defy the laws of physics and somehow turn itself back around from ist inital trajectory to hit the engine.

          Or maybe ricochet back off a containment ring!

          I don’t think Boeing will be all that thrilled about this and the Operators even less so.

          More weight! I also wonder how they would fasten hese new Containment rings.

          • If a blade breaks, it will initially hit the nacelle. If the nacelle is reinforced against penetration, the broken blade will bounce around until it finds another exit path. The least destructive path is out the front (or the back if it’s a rear turbine). That’s all I was saying.

          • You might not know exactly the borders of the engine and nacelle. The engine “bare engine” as certified by the engine manufacturer and the QEC “Quick engine change” parts with nacelle to make a complete powerplant to be installed onto the aircraft. The engine is tested and certified in an engine test cell with test cell intake and exhaust, including the fan blade out test that shall be contained by the engine together with a safe shutdown. From earlier accidents there is also a containment ring in the engine air intake that is a nacelle part. In this case it was a bit short and did not catch the fwd flying part of the released fan blade. Since the fan bladeout test is done with a test intake “Bell mouth” it differs from a high aircraft speed high rpm climb out fan blade failure. The nacelle designer must design for the blade out and aero loads and this can be hard to get correct, especially as each fan blade out event most likely give different loads onto the engine and nacelle, manly due to variations in rubbing torque against the fan rubstrips and containment case. One problem is that if you increase the inlet containment fwd you change its mass as well and the whole engine nacelle/pylon life and stress has to be redone.

        • Thank you Claes, that’s good information and it helps in understanding the issue. I’m sure the solution is more complex than I’ve represented here.

          • Guys:

            It needs to be noted here that while the blade did the cowl damage, it was a LATCH that went into the cabin.

            It likely is easy enough to beef up the latch or have a restraint for it and certify it. I believe that is why Boeing can comply.

            As its so incredibly rare there is no test for this and they do not understand the dynamics to crated one.

          • Thanks TW, that’s helpful. I read the report but did not fully understand.

            It said the containment ring did not fail and there were no penetrations of the fan case, but there were impact markings within the case and a breach hole at one impact, that was consistent with other external damage. Also that the front cowling was largely destroyed.

            I took that to mean that the blade shattered as it bounced around, eventually moving forward into the cowling area, but perhaps initial shattering and scattering of shrapnel would be a more accurate description of the failure mode?

            I also wasn’t clear on the difference between a penetration (there were none) and a breach (there was one)?

            I know there is an incredible amount of energy released in that event, that must be either absorbed or redirected. As you say, it’s very difficult to model or test.

    • I don’t think they were replacing pickle forks, they are getting banded to stop the crack developing further.

  6. Melius’ forecast is entirely based on Boeing’s current build rate studies with suppliers, based on Boeing’s push to get the Max flyable by EOY and is therefore in my opinion, completely too optimistic.

    There has been so much disruption in the supply chain this year and companies are looking at laying people off while machines are sitting idle. I seriously doubt the supply chain will in any way be ready to support 57/mo before 2021 as the attempt to reach it before the Max crisis already caused massive material shortages and chaos with the mills which hasn’t completely recovered yet.

  7. Boeing as a company does not seem anywhere near as worried about the 737MAX or its corporate future as many posters on (even the more thoughtful) aviation discussion sites. I asked a former classmate who works at Boeing Defense if their entire aeronautical and systems engineering staffs were being sent up to Renton to work on the MAX and she reported that other than a few small work packages there was no desperate assignments of MAX (or NSA) work to the BDS world.

    One would think that if Boeing believed it was headed for Chapter 11 (or even complete breakup) as a result of the MAX situation being worse than revealed that all other work throughout the company would be on hold and all resources focused on the MAX as happened during the Saturn V crisis, but that does not appear to have occurred. Yet some reasonably knowledgeable persons [1] here and on similar forums believe that the problems _are_worse than revealed [2]. There have been more flights of the BOE1 test aircraft in the last 7 days with extreme flight profiles; perhaps we will soon know one way or the other.

    [1] and who are not members of the fanatical “Boeing must be destroyed and the earth in Renton salted” faction

    [2] noting as usual that no airframe manufacturer is under any obligation to reveal design or regulatory information to the general public, other than as provided by law

    • All that (Boeing not mobilizing the troops) means to me is that they are going about business in the same fashion that got them into the mess. I don’t see them getting ahead of the thinking. They claimed they had a fix for May, then Peter Lemme whose expertise is in electrical engineering suggested dual computer architecture. The articles in the paper quote Lemme or Leeham. If Boeing has a bunch of PhDs of aero engineering, they aren’t heard from. Is this Transport Canada suggestion to remove MCAS a rational idea? Where is Boeing’s expertise? Is it that muffled by their PR and legal machine? I think that muffling their best and brightest behind closed doors just adds to the confusion on complicated issues and drags on the grounding.
      I’ve heard Leeham’s conjecture for exactly why MCAS was needed to pass an FAA test. But where is Boeing’s explanation to the public? If they’ve got the smartest aero people in there somewhere, they ought to break them out to instill a little confidence.

      • Shifting of workforce usually is less efficient and can even lower it.

        Also keep in mind, what is there for people to do?

        The rate has dropped back. You have a whole workforce of pilots doing nothing as they can’t fly delivery flights.

        Workload for now is down, and they are looking at the gear up to delivery lot of aircraft and have had plenty of time for planning.

        Clearly if the MAX is release to deliver it will get busy and there will be the ups and downs.

        I am not going to sp0eculate on how fast they can clear backlog, all the inside planning is being kept there so until we see the first few months of delivery we won’t know how well done or not.

        The skill set from the defense side does not translate into an assist to the commercial side for the most part.

        I would actually call that wisdom in letting commercial work its issue out without disrupting other programs.

        • Boeing is producing 737MAX’es at a steady pace, paint, test fly them and deliver them to desert storage to be ready for customer acceptance flight after FAA AD incorporation and depreservation. Most likely they have a team in each desert doing inspections, replacing dehumidifying bags and represerve its engines.

      • @Ted

        “The smart aero people” at Boeing are long gone: they have either retired, been forced out, fired, or went to work in fields as far away from aerospace as they could get. I know a few who quit Boeing to go to med school. Those who are still at Boeing are ‘cowering’ to the recent bon vivant MBA grads/puffed up toughs, or hiding under their desks hoping they can survive just a little while longer.
        “Smart” has no place at Boeing. In an environment that thrives on generating growth by bending basic technical facts one at a time, the smart aero folks are a mortal threat, and muffling them is not only good business, but is essential to the survival of the management. As a way to keep them in control, most of these engineers are underpaid; a friend used to describe the average Boeing engineer as being ‘one broken refrigerator away from bankruptcy’.
        The current management demands from the aero people to behave like sheep, do no thinking, and (if needed) alter their results to always please the program managers and mid bosses. Having known many of them, the kind of engineers who are trapped in this environment will instill no confidence in anyone, should they ever be rolled out in front of the public.
        So I guess you can say Boeing is reaping what it has sown regarding their talent management philosophy: they have very little left.

        • So far this is the best explanation that I have seen regrading the very troublesome aerodynamics of the MAX.

          Thank you A Jones

          • Between all rosy and gloom and doom.

            787 was an amazing technical feat as was the 747-8.

            I suspect the 777x will be as well.

          • @TW: Really? Are you kidding?

            The 787 doesn’t even outperform the A330neo really. If you ask me that’s very mediocre performance. A full CFRP plane that doesn’t outclass a decades old design that is full aluminum.

            The 747-8 is a total failure if you ask me. But in this case the engineers had to live with a lot of old stuff, so it’s hard to tell if they would have done better if they were allowed to work “free”. But checking with the 787 I’d say not.

            The 777X is again hampered by old basic designs, but I doubt it will stand a chance against the A350, which is now again more than a decade older.

            The 777 was the last really great product development. After that I would rate the engineering performance of Boeing as being mediocre in average. To convince me that they are doing “amazingly” you would need to throw a couple of stiff drinks at me and drag me into a long argument.

          • That is a fallacy.

            The A330NEO has some advantages, put a new engine on the 787 (well unless its an RR) and those all go away.

            Is wishful thinking the A330NEO is overall better than the 787.

            Have I mentioned those A330NEO engines that need all new fan blades ?

          • The engines of the A330neo are almost identical to the one of the 787. The only big difference is that they have bleed air. I’d be happy to learn from you in which way they are better. The 7000 has the same core as the TEN, the bypass ratio and pressure ratio are exactly the same…

            I did not state that the A330neo is superior to the 787 in its overall performance. What I said is that its performance is on par with the 787 though it’s much older and made from heavier aluminum. That’s why I think the Airbus engineers have done a much better job.

            Thanks for giving me a chance to point this out again.

    • your “insider” report is less than surprising.

      The people Boeing needs for laundering MAX frames to make them customer ready are not working at Boeing. Either they were fired or retired in recent history. ( and the job notices have been published already.

      Then I am in support of creating a long lasting lesson for Boeing ( and to a degree the FAA). “Expensive” probably works best in a profit metrics domain.

  8. So the “can we deliver max frames before MAX RTS, pretty please” was just injected for leveraging incompetence in the share holder domain?

    Spice ( er Dollars ) must flow!

  9. The MAX has taken such a huge PR hit that it seems likely to affect sales at the margin for years to come. They’ve already lost the A321 battle as well. Once they get past the initial recovery, they should think about a 737 replacement so they can improve their competitive position against the A320/321 instead of limping along indefinitely losing ground.

    It will probably take 6-7 years realistically to deliver a replacement aircraft plus one or two years to get started, which will work down the existing 737 backlog. There’s no way they will be able to do another update to this venerable aircraft. The longer they wait to bite the bullet on a new design, the farther behind Airbus they’ll fall in the most important product area financially.

    • Uh Earth to Nick, they never were in a battle with the A321.

      They lost that as soon as Airbus created that version.

      Much like Airbus never had an answer for the 777

  10. @Ted: “Is this Transport Canada suggestion to remove MCAS a rational idea?”

    It’s the most ludicrous idea I have heard in a long time. It’s actually a disgrace because it originates from the head of risk assessment at Transport Canada.

    Hey guys I found a magical solution for all the problems we have encountered with MCAS. Let’s get rid of it!

    Of course MCAS is required to satisfy some FAA regulations but let’s bend those rules and be done with it. I am sure we can all agree on that. After all Christmas is approaching fast and we have been at it for almost nine months now.

    Wow! This is one of the most spectacular brain failure I have witnessed in recent memory.

    In order to understand this kind of behaviour one needs to know that marijuana was legalized in Canada recently and it seems to affect the judgement of some high-level Canadians.

    I mean if this guy had made this suggestion around a cup of coffee on a Monday morning after a frustrating weekend I would understand. But hey, this was shown to the world via a well structured Power Point presentation that must have taken many hours to put together. That is what makes this proposition so astonishing to me.

    Honorable Marc Garneau, before you remove this gentleman from office please bring in the white coats because this guy needs help.

    • He might be smarter than us and have flow 737MAX simulators many times in these conditions and came to the conclusion that the non-linearity of stick forces at those aft c.g. and alfas could be handled by pilot training (in Canadian built simulators) and modified regulations. This compared to the risk that the computers get a hickup and start giving wrong signals (we are in Microsoft country) and the stabilizers go wrong again.

      • Or maybe he is really cunning, provoking exactly this reaction and finally getting Boeing to reveal that the MAX is not operable without MCAS. Which would make quite a difference to basically everything, right?

    • I’m no expert but it seems like the logical and best solution. If stripping out MCAS is unlikely to cause an accident during the entire lifespan of the MAX then there is no reason to keep it and there may be slightly more risk of human factors problems and malfunctions from its retention. I have come to realise that rules are bent all over the place during airliner development, sometimes with good reason. Grandfathering is a massive bending of the rules and the MAX rudder cable arrangement breaks them, are you proposing stripping it out and installing a new system in a thousand aeroplanes? I’m not sure if that decision was correct but it’s pointless ignoring accident probability statistics just for the sake of consistency.

    • Judging by Airbus’s rising share price, there’s at least some out there seeing what’s likely to be the writing on the wall for Boeing.

      Also there’s possibly a small amount of market encouragement going on. Whilst the pretence that the company is headed places can be maintained, whilst there’s no solid financial report data to the contrary, buying and selling shares can remain profitable. The trick is to not be holding the shares if it eventually turns out that the company really is in deep trouble. So whilst we have Boeing saying “everything is going to be OK”, there’s opportunity for investors because someone somewhere will believe that (especially with such a long order book for 737MAX).

      Given that some of the shareholders are Boeing senior management, it’s not in their interests to give a true picture of doom and gloom (if the situation really is doom and gloom) until legally obliged to do so by SEC accounting regulations, or until it’s too obvious to hide anymore.

      Boeing did submit something to the SEC some time ago about financially significant news being in the offing, but I don’t know if that news has ever been actually delivered and identified as such. It was around about the time the first revision of the FCS failed the shouty-sensor data overload issue.

  11. Note: The Airbus CEO G. Faury interview was probably prescient as far as NSAs from both Airbus and Boeing. With that many orders for Coke and Pepsi going forward, they ain’t going to change the recipe. Boeing’s going to hope and probably get more orders for MAXs and Airbus the same with the A320 line. Some reiterations, but more like PIPs, no “next generations.” They want big changes in the technologies to do a whole NSA. Those airlines with demands for a new 150 – 160 two class ride can only ask for the stretched CSeries, the A220-500. Boeing and Airbus aren’t too worried about the “Green New Deal” either.

    • 100% right. A new program takes 20 years to make a decent profit. Nobody knows what the world will look like in 20 years.

      • Sam and Martin, you are both wrong. What Faury isn’t saying too loudly now is that they are already working on new single aisle concepts. You should also have noticed that RR is apparently working not only on an Ultrafan engine for wide bodies (A350neo) but also on a second, smaller version. They have already purchased a second 747 for testing. Airbus has also developed a CFRP wingbox for the A320, which can be the anchor for a full CFRP wing. Then there’s the option of integrating the advanced A220 cockpit into the A320 (or maybe it will be called the A360?).

        Airbus is also researching all kinds of hybrid drive. Here is Europe we are apparently more aware that climate change is a fact and that carbon emissions must be reduced now. And though air traffic is not the single biggest problem, a CO2 tax is just around the corner. Boeing should not sleepwalk into this.

        Oh and yes, if you care to take a closer look, you can get a pretty good image of how the world will look in 20 years. Those who say we don’t, in my experience are those who just don’t care.

        • You are right about Europe being more concerned about the Climate Crisis. And I presume you are correct about research being done to come up with aerospace solutions for less carbon emissions. Actually, I think one of the reasons Delta has ordered over 100 A220s is because they are looking into the future and seeing the CO2 tax around the corner. But I got more of a MBA whiff of Faury from the interview than an environmentalist. There are responsible CEOs, but due to recent events I’m a little cynical. A greener plane would mean lots of jobs.

        • I don’t for a moment think AB will stop development work, but I’m suggesting that what goes into production in the near future will be developments of existing aircraft. 787 showed us how little is left to gain from fusilage and aero design. I don’t think we will see a new clean sheet design enter service before 2035 and only then if a new engine concept has become available. Apart from questions about open rotor or fuel cell powwer, a lot of the shorter range market is being eaten by rail, so market projections are open to question as well. An OEM needs better than 95% security that a new project will pay for itself. They don’t have it.

          • Did Boeing have 95% security when they launched the 747? Die Airbus have 95% security when they launched the A320?
            Did Apple have 95% security when they launched the iPhone, Microsoft with Windows 95, Tesla, Dyson, Toyota Prius,… or Christoph Columbus heading west for that matter.
            No, truly innovative products are never a save bet. They always involve quite some risk.

            A new engine becomes available soon with with Ultrafan. i expect it will be quite a bit better than the maxed out more conventional designs that apparently have already hit the limit with materials (durability). I’d love to know how much better SFC will be in comparison to the current generation of engines. Regarding the timeline – me thinks they be hung under a wing some time over the next 2-3 years.

          • Kind of funny of all this talk about RR when P&W is way ahead of them in the GTF work.

            I would go with the folks who have made it work and had it in service over the ones who gave us the Trent 1000/TEN/7000 mess (and issues with the 900 being swept under the airplane.

          • TW, apparently P&W is so busy with their own mess with the GTF that they have no capacities to develop a larger geared engine. So for all I can see RR will have an exclusive in that field.

            When a company is in a crisis like RR is there are two probable outcomes: A) they get better or B) they get weaker.

            From their last existential crisis RR came out much stronger – which says nothing about this one, I agree. Do you have any information if P&W are developing something new? Or are they trying hard to finally make a profit on the GTF? It could well be that their strategy is to make this a big business and take away substantial market share from CfM. That’s why I think they invest in capacity, not in developing new engines for the time being.

  12. Boeing wanted to create an aircraft to compete against the A320 neo. They were trying to catch up as Boeing already had the 320 neo flying. They produced the Max. The problem is, Boeing needed to produce an aircraft that did not require seperate training, new simulators, crew can fly both types and most of all, no new certification to compete with Airbus that would have costed another 5 years. Boeing invented MCAS and said 1-2 hours laptop training will do the job, no conversion required.
    The Max can fly without MCAS, but it would need to be classified as a new aircraft with all that goes with it including new certification. Boeing is trying to do everything to avoid all of this, as this would mean that the Max is no longer a competition for the Airbus. Airlines would probably cancel their orders as Boeing would not meet the promises given and Airlines would need to invest heavily. Also, crew rostering would become a problem.

    • Peter, we don’t know if the MAX is airworthy without MAX! EASA has demanded test flights with MCAS shut off. It should have been quite easy to arrange such flights and to get this request checked, but as far as I know it has not happened. Now you tell me why.

      • One possibility – they can’t find a test pilot willing to fly it without an escape hatch + parachute or ejector seat? I hope I’m joking.

        Speaking of escape hatches – the prototype Concordes had an escape chute. Open it up, jump into the chute, find yourself dropping smoothly outside the aircraft, pull the ripchord and drift down to a soft landing. I don’t know how many other aircraft in development have had such an arrangement.

        • We know the MAX flies fine without MCAS.

          There is a clear line between “Airworthy” and the regs.

          Regs say they needed to do something about the pitch up.

          Airworthy says its not an issue and you train the pilots it has a slightly odd pitch up at stall (which you don’t do in an airplane anyway)

          If your stick shaker goes off you are looking at attitude and VSI already and taking action if those prove you have hosed it up.

        • Mathew:

          did they ever test it? (grin)

          Ask the Russians about the system on Soyuz that had many non manned crashes and killed one astronaut before they got it sorted out.

          • I don’t believe they ever did!

            If you get to visit one (you can walk through the one at Duxford) you can see that it really does look like a very comfortable chute – smooth sides, a hand rail, gentle curve from vertical towards the horizontal for the smoothest entry into the slip stream, etc. Probably not to be used at M2 though…

            To get even more off thread, I read in the Telegraph today that the EASA will be doing its own certification test on the 777X. That probably wasn’t in the original schedule Boeing had planned.

        • “I don’t know how many other aircraft in development have had such an arrangement.”

          A380, A350 ( just off the top of my head )

    • Going on Boeing’s own accord Airbus was just about stepping into NG territory with the NEO. MAX was a pre lunch action to trounce the NEO soundly. :-)))))))))))))) sales numbers reflect that nicely.)

  13. If there is one fault with Leeham, these articles are it: re-reporting sellside analyst reports as something newsworththy.

    As the byline here says, “There’s more to real news than a news release.” But these articles fail the test, again and again.

    Just because investment bank equity research have some scarcity value (i.e. sent to financial professionals, and not mainstream audience), doesn’t make them any more credible. In fact, they are are generally some of the dumbest reports out there, just couched in intellectual-sounding finance doublespeak. Some of them are borderline lunacy. (Sellside reports DO have one useful role…although we have rules against it, inevitably they get printed out in the office. They make a fantastic source of recycling paper, and admittedly, fire starter under the logs for the holiday season.) Sadly, my job has required I read them for well over a decade. I am definitely dumber for it. Please stop holding them in high regard and writing articles about them which, de facto, give them respect they ill deserve.


    • @Stephen: You miss the point of reporting these analyst opinions, but being in land development, this doesn’t surprise me.


      • Stephen: Clearly you have missed Bjorns reports which are highly detailed.

        While I understand your post work Trauma (I call it PTWS) I feel Leeham does a very good job on offering up information and a forum for views on that information.

        While I disagree on some of the analysis, Leeham also has a huge reservoir of data and people skilled at using it. Likely long term they are right.

        The key stuff is paywall only and for understandable reasons of business (that is how they pay the mortgage)

      • @Scott Hamilton and @TransWorld

        I didn’t miss Bjorn’s reports, I am an avid reader. And relatively long-time paid subscriber to Leeham, so indeed I read everything on here.

        I’m not sure if Scott you were making a joke (which I obliquely missed) or not. But I am not in real estate. I sadly admit to financing “more than a few” of the very companies you write about on here.

        I stand by my comments about sellside reports. And if we’re really splitting hairs, these are not”investment banking analysts,” but rather humdrum sellside stock analysts sitting on the bank’s cash equity sales desk. They are simply not news. Just like Melius’s CF guesses aren’t worthy of print either. They are routinely wrong. Who cares what he has in 2021? Did you see what he predicted for this year’s cash? Why is it worthy of print? And anyway, let’s say sellside reports are worth a write-up once in a while. Why Melius? And why his, instead of Morgan Stanley’s, Goldman’s, JPM’s or UBS? If I flip through Thomson, I can see updates on BA nearly every day by one of the banks. It’s just cherry picking.

        I don’t mean any offense by it. This is just what I do for a living and it’s clear Leeham is playing an away game with the financial industry color. Especially since those guys aren’t really the main players anyway. Nobody who matters and is going to buy the stock, underwrite debt in size or invest a real book into finance leases cares what Bernstein says.

        • Well, the Melius prediction for Oct 2020 of rate 25 from the backlog, plus rate 57 seems like the best case scenario. Boeing has a recent history of being overly optimistic on the 777 and 787 production and deliveries, so I really don’t think those numbers will come to pass. There’s a worst case scenario, which is the RTS is delayed past summer with more software or hardware changes. In the middle, I see deliveries starting in Feb., maybe rate 15 from the backlog taking 3 years to clear out. Rate increases, who knows? Conservatively I would think it could remain at rate 42 for a few years as well.

    • The people that predict elections best are the bookmakers taking bets. When there is money involved the prejudice and bias is ignored.

  14. If you accept that separate simulator training is going to be needed, could the desired crisp edge of stall characteristics be achieved by making the MAX stall slightly earlier? This is probably a dumb idea,I know.

    • Probably not but I would not call it dumb.

      They make tweaks on wings and twist and such all the time to achieve desired operating characteristics.

      More just too costly and not feasible.

  15. IMO mandated simulator training is going to be the key factor in stretching out RTS for the MAX.
    Because the force needed to move the smaller ( from NG onwards) trim wheels manually is clearly excessive the requirement to use the roller coaster maneuver is clear – hoping that the needed altitude is available – and that will need training on MAX simulators which have been recalibrated to reflect actual forces. Very few of these exist and that will be a bottleneck for sure.
    Imagine if ALL 737 pilots are required to be retrained over a reasonable period of time?

    • Frankly I think they have to be as the fidelity of the 737 Sims was wrong and therefore their training has a gap.

      I am willing to bet that they will have a grace period to get it done.

      And the maneuver is not required in all flight conditions, higher speed is the issue.

      What they do about the clutch breakout is probably the most challenging.

      And should this feature have been allowed to continue onto modern production aircraft?

  16. @Matthew: “The result of all this is the probability that with a disabled MCAS the aerodynamics are unacceptable.”

    To my mind this is more a certainty than a probability. That is the reason why EASA calls for flight testing the MAX with MCAS disabled. If this test is carried out it will likely fail.

    Otherwise how would you explain that after the initial flight testing of the MAX the Boeing engineers felt the need to immediately modify MCAS so that it would activate by increments of 2,5 degrees instead of only 0,6 degrees?

    In other words once they started to fly the MAX back then they felt the need to multiply MCAS power by a factor of four. Which indicates to me that the MAX has serious aerodynamic deficiencies that were only discovered after the flight testing campaign had been initiated.

    @Matthew: “Does that promote MCAS 2 from “nice to have” up to “essential for flight at all times”?”

    No it does not. MCAS should never be required during normal flight. It was designed to address two issue when the aircraft is flying in extreme conditions.

    One issue is at higher speed, which was predicted before the flight campaign was initiated, hence the 0,6 degrees increments; the other issue is at lower speed and was discovered after flight testing had already been initiated, hence the 2,5 degrees increments.

    These two problematic conditions have a low probability of occurence but are there nevertheless. The essence of aircraft safety is to prevent anything that could happen from happening in the first place. That principle is what made aircraft safety at the level it is now.

    @Matthew: “If so then Boeing’s implementation is woefully inadequate.”

    Boeing’s implementation is a lot more that “woefully inadequate.” It is absolute garbage and has seriously compromised Boeing’s reputation.

    Now that they have realized this they are trying to bring corrections but the difficulties encountered during this process appear to be insurmontable. That is where the desperate call from that Transport Canada idiot comes from.

    • Hi Normand,

      The Seattle Times has reported that Boeing has long since conducted MAX flights with MCAS turned off. These flights will also be conducted with the FAA present. The FAA will then share the data with other regulators. We will see if EASA actually ends up not trusting the FAA and demanding their own test flights.

      Boeing says MCAS is needed not for stability but only to make the MAX feel the same to a pilot as the previous 737 model. The airplane will fly safely with or without MCAS, Boeing insists.
      To prove that, Boeing has flown near-stall maneuvers in flight tests this summer with MCAS turned off. Safety regulators plan to do the same during upcoming recertification flights.

      People seem to think that just because Boeing hasn’t publicly released detailed flight test data, that they are somehow afraid of conducting these tests and that the tests will “fail”, whatever that means. Well, it looks like these tests were already done months ago.

      This test was also inadvertently run when the flight before the flight before LNI610 flew the majority of the time with MCAS disabled due to a non-functioning AoA vane on the left side. Other than altitude and airspeed disagree alerts, no handling problems were reported.

      • Mathew

        Thank you, pretty funny, that is how they found the MCAS region, in test when it did not exist as a program!

        Granted it was test pilots but no balls of aluminum on the ground.

        As a pilot I find it a hoot (as a concerned aviationist I deplore the loss of life so don’t get me wrong)

        If I even got to stick shaker, with cross scan confirmation I would would be pushing the nose down before MCAS could kick in.

        As a good pilot I would have done my scans and not gone there.

        A bad outcome is that Lion may get away with its lousy maint and pilot training as a result of what Boeing did.

        • @Transworld, methinks you were replying to someone else’s post (Normand Hamels?).

          I don’t think that Lion Air were particularly let off by the official report, though I agree that there’s some distance between a critical report and actual consequences for personnel, ammendments to company procedures, etc.

          • Mathew:

            Have to go back and cross check (grin)

            I fear that the Boeing debacle with the Indonesia mess of enforcement leaves them an excuse and they will not address it and Air Asia and Lion will continue to crash and kill people.

            Yes, Boeing has to be held as fully accountable as we can.

            But I do think a decently trained crews could have survived both events.

          • The FAA revoked the license of Xtra Aerospace in Miramar Fl for handling parts they werent authorised for and poor record keeping.
            They were part of the chain of repairs for the AoA vanes.
            So much for the meme floated that its onlythose shoddy asian repair shops

          • Duke:

            This is not about first or third world though there may be some relevance in pilot training and experience requirements.

            Lion Maint did not do the tests to confirm it was right either.

            So, Lion pilots did not write up the issue nor what they did to get around it and the maint shop just thinks you stuff a vane on and the job is done.

            I would call that shoddy work.

      • Hello Mike,

        The stability issue is a myth and what Boeing says about it is actually a digression. Let me quote The Seattle Times again:

        “Boeing says MCAS is needed not for stability but only to make the MAX feel the same to a pilot as the previous 737 model. The airplane will fly safely with or without MCAS, Boeing insists.”

        – Boeing says MCAS is needed not for stability: True

        There has never been any stability issue with the MAX except in people’s mind.

        – But only to make the MAX feel the same to a pilot as the previous 737 model: False

        I object to the word “only” because Boeing is not saying the whole truth here (which is not the same as lying). Yes MCAS was designed to give the MAX the same handling characteristics as the NG.

        Boeing did this to save on pilot training because without MCAS the MAX would have been treated as as a different type of aircraft, hence some additional training required for existing NG pilots.

        However, there is another reason for MCAS that is much more important than giving the MAX the same handling characteristics as the NG and that Boeing does not openly discuss.

        It has to do with existing FAA rules that require any commercial aircraft to fly smoothly into a stall.

        This is correlated to back pressure on the stick, for the stick force can become spongy on the MAX when approaching a stall and that can be dangerous because it might allow a pilot to go too deep into a steep turn, which could lead to a pitch up condition if not handled properly. It would be the same, only worse, if the centre of gravity was too far aft at low speed.

        That rule must be satisfied, there is no discussion here. But it does not have to be addressed with MCAS. Boeing could do it aerodynamically, but it would penalize the MAX by adding drag and weight.

        – The airplane will fly safely with or without MCAS, Boeing insists: False

        It will not fly safely for the very reason I have just explained in the previous paragraph. In normal flight yes it will be as safe as any other aircraft. But not if for any reason the airplane finds itself in one of the two conditions I have described above: steep turn, which is a relatively mild issue, and aft centre of gravity at low speed, which is a more severe issue.

        So if EASA requests the Boeing pilots to execute these extreme maneuvers with MCAS deactivated I am sure they will handle the plane perfectly and recover without further ado. But that’s not the issue here.

        The problem remains: That is without MCAS, or any other mean judged appropriate, the MAX does not meat the FAA requirements regarding the airplane handling characteristics. That is what currently makes the MAX an unsafe aircraft.

        • Normand,

          Great post! I have to say I agree with everything you said in your reply to my comment. Perhaps with only two small exceptions.

          I totally agree that the MAX is statically stable in pitch over the entire flight envelope up through stall. I think we will also both agree that there is a real handling issue at high AoA close to stall that needs a solution such as MCAS so the MAX can be certified by the FAA. Where we might diverge now is perhaps only semantics.

          I would call this handling issue at high AoA a pitch stability issue because it has to do with a slope change at high AoA of the pitching moment vs. AoA curve. Let me again emphasize that I think the MAX is statically stable in pitch in this regime. It is just a bit less stable in this regime so I would call it a stability issue.

          This is way different than the awful stability issue that some people imagine exists despite the lack of any technical evidence to support it.

          The second small exception would be your supposition that an aerodynamic fix exists that could replace MCAS. I’m not 100% convinced this is true. Boeing is said to have considered aerodynamic solutions, and in fact, the chief test pilot really advocated for it. However, the engineers came back and said that they didn’t have enough confidence that any of the proposed aerodynamic solutions would work, so MCAS was pursued instead.

          After all this, I agree that from the standpoint of FAA regulations, the MAX without MCAS or any other replacement solution is officially not safe to fly. It should be noted that this does not preclude the possibility of MCAS failing safe by shutting off if there is an AoA disagree. If I’m not mistaken the regulations allow for a restricted flight envelope in the event of inflight equipment failure.

          • Mike,
            “Boeing is said to have considered aerodynamic solutions, and in fact, the chief test pilot really advocated for it”
            When the original MCAS iteration was done, that was under test plot Ray Craig, who was advocating for a hardware fix. The later MCAS extension, under test pilot Ed Wilson, was the more powerful version, and he wanted MCAS from what I’ve read. These two functions of MCAS keep getting blended together and confused. They were years apart in their development history.

          • Richard,

            You’re right, the two MCAS functions were years apart in their development. However, I think it was early on when the engineers concluded that their confidence level in any of their aerodynamic fixes was low. While the first test pilot had to be convinced that aero fixes were probably not going to work, the second test pilot came in already knowing this because of the previous work.

        • “I object to the word “only” because Boeing is not saying the whole truth here (which is not the same as lying). ”

          If you withhold facts that change what is reality, then that is a lie.

        • Mike,

          It seems there is some semantics involved.

          The reality is, there is already a stick shaker and a stall alarm.

          All MCAS does is smooth the response to feel like a NG all the way into the stall. Bjorn has stated that.

          They have stalled the 737 without the MCAS. It just stalls and falls off (no wing flips, no upside down, no barrel rolls)

          By the time MCAS activate (real stall) the pilot should be well on the way to stopping the stall (the stall they will never see in a lifetime of real cockpit time)

          If they stall it, only MCAS 1.0 would get them out of it (sadly at the other end of causing a crash ).

          Ironically while not intended, MCAS 1.0 was real stall protection with its ability to move the stab full deflection in a short time period.

          I guess limited envelope ops means don’t stall it like you would not be stalling it anyway.

          The only time pilots see a stall (fairly recent addition by the way) is in the Flight simulators (or if they flying small aircraft and do them) .

          • TW, Does MCAS activate before the stick shaker or after it, or depending on it’s AOA/Mach schedule table? I’m thinking that if a stick shaker activates, the pilot would notice and take appropriate action. MCAS is there moving the stabilizer to help him by lowering the nose and increasing the stick force.

          • RD:

            I have not seen the schedule of when it starts is activity.

            It would seem as the pitch up starts which would be at stall (bank angle plays in here as well)

            Stick shaker will start before that as its a warning coming up to stall not in stall.

            Our version of the stick shaker was a buzzer that was linked to a tab on the wing. As the airflow started to get disturbed it wold go off.

            You could fly on the ragged edge depending on tone (with altitude, not something you messed with on approach)

    • @Normand Hamel,

      From what we do know publicly the case for the MAX’s aerodynamics being junk is pretty strong (e.g. the late ammendment to MCAS, it’s existence in the first place, etc). However, what I can’t square is the aero being junk, the EASA’s long standing assertion that they’re going to fly the MAX for themselves, and Boeing’s apparent willingness to go along with such a flight (I might have got that last one wrong). If the EASA’s findings on that flight are not good, the MAX is likely in even deeper trouble. Boeing have got to know that, and they’re either fooling themselves into thinking that the EASA could somehow be overridden, or that the aero really is bening (but not like the NG).

      What I think Boeing are missing is that, if you’re going to have a system like MCAS on board, the natural benign nature of the raw aerodynamics (or otherwise) is irrelevant. What is relevant is the requirement for MCAS to remain benign under all fault conditions.

      Boeing seem to be of the view that duplicate redundancy is adequate to bring recurring crash rates caused by MCAS back down to acceptable levels. Correct me if I’m wrong, but I think we both disagree with that.

      My view is that with this complex new limiting functionality in MCAS (specifically “detect high AoA event”) having been quickly specified, quickly implemented, and implemented by one single team (AFAIK), there’s too much scope for a fatal problem to have slipped through the cracks. What if that “detect high AoA event” function is incorrect *and* two faulty AoA sensors are installed? The former might enable repeated MCAS activations despite the other limit “one activation per high AoA event”. The latter might tell the FCS that MCAS activation is needed. Result: more crashed aircraft.

      My point “essential for flight at all times” was poorly worded. I was really referring to the possibility that the reliability requirement for MCAS 2.0 should be much higher than could be achieved with only duplicate redundancy channels, if the aerodynamic behaviour in the extremes of the flight envelope were unacceptable. Granted a flight should never normally reach those corners, but if it does perhaps it’s safety critical that MCAS is there to save the day. If (as seems unlikley) that those corners of the flight envelope are officially benign, then MCAS’s sole function is as Boeing insists – to make it feel like an NG, but it’s still safety critical.

      • What you do not get is all that occurs is pitch up into stall which in turn has a negative VSI.

        Nothing awful happens as posted previously.

        They stalled the MAX repeatably prior to MCAS.

        If you yanked the control back you probably can still stall it despite MCAS.

        In the end all the protections of MCAS 2.0 give the crew the opportunity to recognize the issue and turn the stabs off for which they will be fully aware and trained for.

  17. May I say that your posts are excellent Mr Hamel.

    One must assume though that the MCAS issues are not insurmountable- whatever one ‘idiot’ says.
    And he is an idiot as he would not have made the comment he did (remove it) if he had any deep knowledge of the issue and what the FAA will and will not accept on an aircraft.

    Whether people ( here or otherwise) accept it,clearly the FAA do allow software to overcome certain (extreme?) aspects of flight instability within the flight envelope as a whole.
    Having said that I do agree with the poster that ‘after a suitable time’ has elapsed Boeing will launch a new aircraft.
    It won’t be positioned as a replacement as it will be in the 200-270 seater class ( which is where the market has gone-is going anyrate).
    Perhaps not an ‘all new’ engine as GE has stated it can’t be (‘until the early 2030’s’).But perhaps a geared higher bypass version of their existing engine?

    • I would call the view confirmation bias, not excellent.

      In fact as was pointed out, it flies just fine without MCAS to the point it was late in flight test that it was identified by the FAA as needing a so called fix. Clearly Mr. Hamel in this case does not know what he is talking about.

      Clearly you are wrong on flight characteristics. Fact always trumps fiction. And it is a fact that MAX flew and flies just fine without MCAS and is a fully stable aircraft. Being in denial does not change that.

      More clearly is that there is now two markets, one is the 120 to 180 passenger area and the other is the 180 to 250.

      The lower end is well served by the A220.

      The upper end is currently pretty well served (or best served) by the A321 versions available. It lacks range and has limitations with the fuselage.

      A long time ago it was seen that the A321 was moving to 50% of Airbus SA so that is nothing new unless you are late to the party.

      I find it funny to think that you would feel GE is the one to introduce a GTF when P&W is the one who pioneered it and has designs ready to go into prototype stage even as we speak.

      While RR is behind they are the next closes with some form of GTF. GE is so far behind that they might as well be driving my Ural at the Isle of Man cycle race.

      Clearly you do not follow GE and what kind of financial trouble it is in right now.

      If you actually followed engines, P&W is the best position if they want to tackle it to come out with a new engine or two in the next 5 years.


      Some of its successful division will be spun off and when merged with Raytheon it will be an aviation juggernaut with very healthy bottom line.

      GE and RR are train wrecks.

        • Yes.

          The engine clearly has had issues. While not trying to defend P&W, they have been fixed as they came up, so they are not deep desing issues.

          Some should have been tested but the regs allow all engine mfgs to make those changes without it so its a tough call, do you hold one engine mfg accountable while the others get away with it?

          EASA changed their Regs to allow two (call em bad or iffy) RR Trent 1000 engines on the same aircraft (this was one of the issue with P&W that India put the kabosh on and insisted both engine be good for certain flights)

          My problem with RR is the same problem has been known for 3 years and they did not even understand it until last year.

          RR is financially sick which is why I call them a train wreck. If they can’t fix a bad engine what does that say about a new engine (and keep in mind it took 4-5 years for the current Trent 1000 issues to show up)

          On the other hand United Technologies is healthy, Raytheon is healthy and UT is divesting itself of the non aviation parts so its an Aviation focused company.

          RR has all sorts of interests including diesel engines, ship propulsion systems.


          You will note GE went down this patch and they are dumping stuff now as well

          P&W has the resources if UT/RA decide to invest and they have the expertise in thie application that RR is playing with still and GE has not even started with.

  18. Some of the question will not be answer as soon as one would think. At about 7:00 pm Eastern time (Tuesday evening) CNBC ran a story that the FAA is not certifying the MAX yet.

    “For the third time in two weeks, the FAA said publicly it will take all the time it needs to deem the Max safe. The FAA issued a new statement, saying, “The FAA has not completed its review of the 737 Max aircraft design changes and associated pilot training. The agency will not approve the aircraft for return to service until it has completed numerous rounds of rigorous testing.”


    • I am sorry for the long post, please bear with me.

      It appears that there is understandable pressure from Boeing on the FAA to allow the MAX to fly again, and to allow delivery of aircraft to customers as soon as possible.

      “Boeing Chief Executive Officer Dennis Muilenburg requested that the handovers begin in a phone conversation with Dickson, according to the people, who weren’t authorized to speak on the matter and asked not to be named. The FAA chief later reiterated in a statement and video message to employees that agency staff wouldn’t be pressured into hurrying their work.”

      Above from: https://www.seattletimes.com/business/boeing-aerospace/faa-vows-to-retain-authority-over-all-aspects-of-737-max-jet/

      The way that I read Jim Marko’s email is that there are still significant concerns from a technical point of view:


      “How to get some confidence back to us all that we as Authorities can sleep at night when that day comes when the MAX returns to service.”

      “Judging from the number and degree of open issues that we have, I am feeling that final decisions on acceptance will not be technically based.”

      “Hope you can get to look at this soon as we may have some management movement on this aspect soon, at least by TCCA.”

      I haven’t seen any reports to the effect that this email is not genuine, so on the basis that it is genuine, I’m troubled.

      Boeing seem to be saying all is done the MAX is safe to fly, but this email is only dated a week ago … “number and degree of open issues” …

      346 people died, I’m really hoping that the individuals that we are all trusting to ensure that the MAX is safe to fly are allowed to ensure that it really is safe to fly.

      I have some sympathy with Jim Marko’s point that maybe the MAX would be better off without MCAS, if MCAS cannot be certain to not act unnecessarily, then it would be better if it was not present. The cure should not be worse than the disease !

      I learnt many years ago from a very wise man that sometimes just because you can do something doesn’t mean that you should. Sometimes you need to stop, and look at the problem again, and fully understand what you are doing, and attempting to achieve.

      I’m hoping that I am reading too much into this, as they say in the USA YMMV.

      I’m really hoping that I am wrong, but if the MAX flies before all technical issues are resolved to the satisfaction of people like Jim Marko, and Linh Le, I will be very worried.

      • “” Muilenburg requested that the handover deliveries of aircraft to customers begin in a phone conversation with Dickson “”

        Did Muilenburg provide the software audit?
        Damn cash-flow …
        Thanks to the FAA staff for keeping the public informed.

  19. @Mike Bohnet

    In regard to the MAX stability problem I had already realized my mistake before I read your reply. I should have added a caveat to my initial assertion. Here is what I had in mind when I said that the MAX stability issue is a myth.

    I was thinking about the informed public at large that likes to vue the MAX as a Rodeo Airplane, or a Parkinson Aircraft. And because of that a surprising number of people still think that MCAS is active all the time. Which is completely false.

    That being said, it is well known inside the aviation community that the MAX has a longitudinal stability issue that MCAS tries to compensate for. The NG did not have such a problem. Boeing knows this and that’s why they went to great lengths to avoid separate certifications.

    Unfortunately it backfired on them. But they deserved all the pain and suffering that came with it because they have betrayed the engineering profession and have destroyed Boeing’s reputation in the process.

    As for the aerodynamic solution I must admit that I don’t really know. But I still presume that something can be done to alleviate the longitudinal stability issue via natural means. However I recognize that there might be too big a price to pay for a compte aerodynamic fix.

  20. @Mike Bohnet

    In regard to the MAX stability problem I had already realized my mistake before I read your reply. I should have added a caveat to my initial assertion. Here is what I had in mind when I said that the MAX stability issue is a myth.

    I was thinking about the informed public at large that likes to vue the MAX as a Rodeo Airplane, or a Parkinson Aircraft. And because of that a surprising number of people still think that MCAS is active all the time. Which is completely false.

    That being said, it is well known inside the aviation community that the MAX has a longitudinal stability issue that MCAS tries to compensate for. The NG did not have such a problem. Boeing knows this and that’s why they went to great lengths to avoid separate certifications.

    Unfortunately it backfired on them. But they deserved all the pain and suffering that came with it because they have betrayed the engineering profession and have destroyed Boeing’s reputation in the process.

    As for the aerodynamic solution I must admit that I don’t really know. But I still presume that something can be done to alleviate the longitudinal stability issue via natural means. However I do recognize that there might be too big a price to pay for a complete aerodynamic fix.

    • NH:

      He said, she said you said.

      How can the MAX have stability issues when it barely had flow and I have yet to read a single PILOT comment that there was.

      So which Aviation Community do you refer to? TFH (tin foil hats?)

      • I can imagine the MAX-10 has the same stabilizer. Beside that it’s a new version same as MAX-7 and 777X. Sure they all will be checked deeply.

        As EASA said, they could imagine a transitional time till a 3rd AoA sensor is included, but that might only meant to be for the MAX-8/-9 because they are grounded.
        The MAX-7 might need a 3rd AoA sensor from the start.
        The MAX-10 without MCAS might be certified with only two AoA but I can’t imagine it will be certified with the same elevator.

    • Boeing had been seeking advance delivery positioning, this would seem to be a resounding no.

      Also EASA has been demanding no delegation as a condition for RTS, so this may be a compromise reached with FAA, so the two regulators remain in lockstep. I’m sure there are numerous negotiations between regulators going on in the background.

    • I think a logical step based on past performance, wind back some of the self certifying.

      Be sure Congress will stay low on this..

      “Congress’s encouragement of self-regulation, possibly fueled by significant industry lobbying, raises legitimate concerns about undue industry influence or regulatory capture—that is, when a regulator works to advance the interests of the industry it regulates, often at the expense of the public.”


  21. @Richard Davenport: “These two functions of MCAS keep getting blended together and confused.”

    They are indeed blended together and shouldn’t. The initial MCAS version had a mild 0,6 degree increment and was addressing an issue with windup turns that had been anticipated before flight testing had started.

    The second MCAS version has been developed when the flight testing campaign was already underway and has been initiated after it was discovered that the MAX was prone to stall at low speed with an aft centre of gravity and required a much more powerful 2,5 degrees increment.

  22. Normand, from an admittedly simple force-balance perspective, the issue with the MAX is that the center of lift begins to move forward with increasing pitch, above a critical value (maybe 10 to 12 degrees)..

    So the options are to add a new compensating force on the airframe, as MCAS does. Or create lifting surfaces behind the engines such that the lift areas are balanced during pitch, and the center of lift doesn’t move (or at least not as much).

    In theory, a wing projection or extension directly behind the engines, of equivalent area, would accomplish this, without much additional drag in normal flight. An alternative would be a winglet or stub attached to the fuselage behind the wing. Or perhaps a much larger rear fillet at the wing joint. Or approaching the MCAS solution, add the area to the stabilizer (MCAS effectively does this by changing stabilizer deflection, and thus effective area & lift).

    However I have no idea how reasonable or practical any of this would be. I don’t know nearly enough about it, and am sure there are many more complexities. But I can see why an aerodynamic solution might be difficult, if it requires adjusting center of lift with pitch. I can also see why MCAS would be attractive, as it’s a targeted solution.

    • Rob,

      A fixed stabiliser automatically adjusts the CoL with pitch. As the AoA increases, bringing the nose up, the stabilisers leading edge also goes up causing lift to be created. The lift caused by the stabiliser leading edge going up causes the CoL to move back. The lift produced also wants to bring the nose down.

      A bigger stabiliser would dampen the pitch up tendency. Fixed rear strakes would do the same for the strakes would offload the stabiliser. Fixed rear strakes are no different to a fixed second stabiliser.

      It still boils down to the same argument. If the pitch up tendency is minor, what’s wrong with recalibrating the elevator control logic to increase elevator forces to stop the pitch up tendency in it’s tracks? After all, we are told this is about making the MAX behave like an NG. Of course elevator forces do need to be available. But are they available?

      I don’t think elevator forces are available. I think the MAX failed it’s high speed nose up turn test. Then it failed it’s low speed stall test with flaps up. Elevator forces were not available to properly control either.

      Remember flight deck forces, as experienced by the pilots, are synthetic. All they need is calibration for the purpose of making a MAX behave like a NG.

      Elevator forces aren’t there so they switched to the trim stabiliser. But trim stabilisers are not primary control/manuevering systems. Primary control/manuevering systems require fail-safe redundancy to meet regulations. Equally the stabiliser would need to move faster for faster open loop response.

      You may not be clear about the CoL. The CoL is the centre of all lift produced by the airplane. So the fuselage, wings, engines and tail as well as other bits and bobs on the airplane. It’s not just the lift produced by the wing.

      I will also address the A320/A321 pitch up tendency at extreme aft CoG when subject to emergency pull up. All they – Airbus – are doing is recalibrating the elevator forces by recalibrating the control logic of the elevator/aileron computers. Elevator forces are there, they just cocked up the calibration. I emphase, elevator forces are there. Still taking 12-15 months. But then they will do it right.

      • The only really feasible solution that I can see here is to get rid of MCAS (don’t forget that ancient computer is overloaded anyways!) and install a significantly larger stabilizer AND elevator. With it it would also be easier to address the manual trim forces issue.

        Though this would be a massive amount of work, it would still be easier and faster than to install a new pylon and new landing gear. And a new flight computer including all new software for that matter.

      • Philip, I’m aware that rearward lift area moves the CoL, that was the main point of my post. I was clarifying the basic problem, from the perspective of an aerodynamic solution.

        We’ve had the discussion about elevators at length in Bjorn’s other column analyzing Lion Air 610. Mike Bohnet has also contributed heavily to that discussion. So I will only briefly summarize:

        Airbus uses FBW, computers fly the plane in response to pilot inputs. Protections are embedded in the FBW control law that serve a similar purpose to MCAS, but there is no need for a separate discreet system. Since the computer has full authority, it can use all the control surfaces, including elevator, just as a pilot would.

        Boeing uses FBP, the pilot has full authority, and systems are then created around the pilot to provide protection. Those systems do not have full authority, unless they are specifically intended to override the pilot (such as stick-pusher which does use elevator authority, just as the pilot would, and as FBW would). Outside of that, the elevator authority is reserved for the pilot (or autopilot if engaged).

        For MCAS not to use the elevator, is consistent with reserving its authority for the pilot. Not due to the elevator having insufficient authority. The stabilizer is the surface used for handling trim, thus MCAS also utilized that surface. MCAS was never intended to override the pilot, only to function as a handling characteristics aide.

        Using full authority, the pilot can also override the stabilizer as the handling/trim surface, and therefore all the systems which control it, including MCAS. But the reverse is not true, those systems cannot override the pilot, who retains full authority.

        The fact that MCAS moved the stabilizer to full AND deflection, was a result of bad design and implementation, together with a sensor failure. It was never intended to do that, it would never be necessary to do that. And the pilot still had the authority to override, as the captain of Lion Air 610 did.

        So that leaves us with the question, can MCAS be fixed? I believe the concept was sound, and the problems are addressable. But obviously many believe that the concept is unsound and/or the problems cannot be fixed. It’s up to the regulators to decide.

        The point of my post was, if MCAS is off the table, what other aerodynamic solution can be used. That’s all I was getting at.

        • Steve refers to the argument you have offered as a circular argument.

          “elevator authority is reserved for the pilots”

          Well the pilots used elevator authority to achieve the AoA in the first place. So why isn’t the elevator authority calibrated to stop the pitch up tendency caused by the AoA induced by the pilots using elevator authority?

          Your answer is that it is “reserved” but not to stop the pitch up tendency. Whatever that means. Unreserve it.

          Circular argument. Set a basis that causes exclusion and then use it to justify the exclusion.

          If the elevators have authority they can be calibrated to stop the pitch up tendency in it’s tracks. The elevators are computer controlled, which means the pilots exert elevators authority through computers.

          • Philip, as Mike tried to explain to you, the computer does not control the elevator in the Boeing system The pilot does, or the autopilot, but the autopilot is out of the loop in an MCAS-type situation. The pilot has full elevator authority. That’s what full authority means.

            What you’re suggesting is a system to override the pilot, similar to FBW. It’s fine if you want to suggest that as a solution, but please be aware of what it means, and that it’s not the simple or trivial solution you imply.

          • From Mike’s link slides describing B737 NG:
            “Feel computer adjusts hydraulic pressure according to speed and stabiliser position.
            Actual feel is provided by the higher of A or B pressure.
            During a stall System A pressure 850 psi.
            With no Hydraulic pressure simple spring feel holds the control column neutral” (p41)

            So the computer does control the elevator in the Boeing system. And previously on the same slides:

            “Stall Identification
            [purpose of system]
            The EFS [Elevator Feel Shift] module increases hydraulic system A pressure to the elevator feel and centring unit during a stall. This increases forward control column force to approximately four times normal feel pressure. [inhibit conditions] There are no flight deck indications that the system is properly armed or activated [does remind me of something – do note this system actuates the elevator].
            As airspeed decreases towards stall speed, the speed trim system [STS] trims the stabilizer nose down and enables trim above stickshaker AOA. With this trim schedule the pilot must pull more aft column to stall the airplane. With the column aft, the amount of column force increase as the EFS module increases pressure to the elevator feel centring unit.” (p39)

            Arguments keep mentioning MCAS is all about certification requirements regarding feel, feel augmentation, feel, but we keep seeing stall, stall, stall.

            If NG pilots had Elevator for Feel and Stabiliser for Stall for two decades now why did MAX (when it already had one) introduce a new Feel system on top of the Stall system. Does this make any sense? This violates Boeing’s own preceding logic, and only a very strong reason would justify such: lack of sufficient elevator authority to address the real issue – STALL. This follows Boeing’s own established logic, which is all outside observers have to base their opinions on, given the secretism on peer reviewable data that could be made public under the grave circumstances.

            The onus is on Boeing to defeat those opinions, by releasing the data, yet Boeing entombs it!

            Worse, MCAS is disguised from pilots as an EFS type – “no flight deck indications” against an STS type – with the moving manual trim wheel visual indication, along the way confusing the relative impact of the existing systems. Makes it dependent on a single input sensor, does no mention in the training manuals, misdeclares the system, its effect authority and fails utterly in its fault assessment to FAA.

            With our benefit of hindsight, a preventable accident occurs and Boeing which had all required data, dismisses it with an ineffective procedure, which later only comes to reveal how degraded things already where, the super-human manual trim. All the while, pacifies authorities fears while waiting for divine intervention, ie. the human pilots. Only for another number of trusting victims fall prey of the Boeing 737 MAX atrocity.

            That is criminal conduct at the highest levels of Boeing. There is no excuse, I hope all those responsible for these decisions rot in a dark cell.

            We all have biases, this one is mine, yes this is also emotional, pure reason without emotion is reserved for computers, we wouldn’t be using the human brain otherwise. And since there are philosophers here – a piece of neuroscience by Damasio.

          • Vasco, to clarify, the elevator feel system provides force feedback to the control column. It regulates the force the pilot feels on the column when moving the elevator.

            However, it does not alter the pilot’s direct control of the elevator. The position of the column controls the elevator position, so the pilot retains full authority. All that changes is the pilot’s experience of the force required to move the elevator. This is meant to more accurately represent control forces to the pilot, as well as to discourage control movements that could be excessive or increase the risk of an upset.

            The AoA condition that MCAS is meant to address, is below the critical AoA required for stall. It’s in the range where the pitch stability curve begins to become non-linier, due to an increasing pitch-up tendency. MCAS is meant to generate the forces needed to compensate for that tendency.

            As I tried to explain in the Lion Air column thread, the elevator feel system does not help in this situation because you cannot subtract force from the column, to represent the increasing pitch tendency. You could use it to add force to the column, instead of to the airframe, but that would only mask the aircraft behavior from the pilot.

            So the best way to deal with the pitch tendency, is to apply a force to the airframe to counter it, which by extension also adds force to the column, and satisfies the regulations.

            MCAS is one solution to add the required airframe force. Others may be possible, for example reducing the nacelle lift rather than compensating for it, has been suggested by Keesje. Or adding lift area aft of the engines. Or other aerodynamic solutions, as can be devised and shown to be effective.

            It’s also been suggested that the regulations for this region of pitch stability be waived, so that no solution is necessary.

            The rest of your post concerns your beliefs regarding Boeing. Those are your opinions and you are entitled to them.

          • Vasco

            Spot on. Indeed Boeing are modifying the control logic because the pressure required by pilots exceeded recommendations.

          • Vasco,

            850psi seems low to me. I’m going to do some checking. I am hazy on this, so may be wrong.

            In other words my thinking is the hydraulic pressure may not be there. So it may not be a case that the elevators are too small. The hydraulic pressure may be insufficient to move them.

            But as you say the elevators are computer controlled, even though the control logic is rudementary.

            Oh God this airplane is old. On the one side rudementary control of the elevators, the other side rudementary control of the stabiliser. I don’t know what’s worse.


            It would need a massive upgrade of the control logic for the elevators. I’ll give you that. Note they are performing a massive update of the control logic for the stabiliser. So it can be done.

            Perhaps, the hydraulic pressure may not be there. Don’t know looking it up.

          • Philip, I know this won’t do any good, but one more time, and for the benefit of other readers, the hydraulic pressure applied by EFS is for stick force feedback. EFS does not alter the actuation of the elevator.

            Peter Lemme acknowledges this in his discussion of whether MCAS represented stall identification. This article is in the SatCom link TW provided below. It’s a very long article but well worth a read.

            According to Peter, and to Mike who has also responded to you previously, EFS is a one-way system, it’s purpose is not to alter actuation of the elevator. That was also my conclusion after researching it.

            There is no evidence of an issue with behavior of the elevator or its authority, in any of the reporting from qualified agencies that have examined the issue in detail.

          • Rob,

            I can see the confusion, I too asked Bjorn why EFS was not used to give the MAX, the ‘feel’ of the NG at high angle of attack, i.e. to address that part of the pitch stability curve.

            So EFS could be used to make it harder for the pilot to pull the control column back, and thus alter the ‘feel’ of the column, but that’s all it would do, the elevator itself does not move, it’s just that the control column would require more force to pull back.

            Altering the EFS will not actually change the pitch up tendency of the aircraft.

            A control surface needs to be moved to arrest the pitch up tendency, hence the movement of the stabiliser AND to address the pitch up movement, and in doing so increase the force felt on the control column.

            The elevator still has full authority, and can thus be moved up, or down to it’s fullest extent by the pilot.

            Do I understand this correctly ?

            Please correct me if I am wrong, it’s important to understand the reasoning for MCAS.

            As I understand it even the NG moves the stabiliser AND when the STS detects that the aircraft is approaching a stall, this appears to be the same on the MAX, and thus no surprise that MCAS is related to the STS.

          • Rob,

            I also know this won’t do any good. The auto-pilot moves the elevators. The auto-pilot is a computer. It’s not just the EFS that’s involved.

            The basic point I’m making is that manual moving of the elevators isn’t possible. It needs to be power assisted. That means calibration of some kind. Calibration is some kind of control logic. Control logic can be altered and indeed is always altered by the flight test programme for as I said wind tunnel testing and theoretical analysis don’t get it right.

            So like you, to others. If the auto-pilot – a computer – can move the elevators then the elevators are computer controlled. Unless you are telling me the auto-pilot can’t move the elevators. If that’s the case I wrong.

            So let’s leave it at that. Let’s agree to disagree.

            Just a small point. The MAX has hydraulics with 3000 psi. I checked.

          • JakDak, I think that is a good summary, and accurate. MCAS was meant to be active in the AoA region before the stick shaker threshold. STS effectively extends stabilizer action above the stick shaker threshold.

            In the accidents, the stick shaker was active, so that may mean both MCAS and STS were also active, but since MCAS was inappropriately unbounded, it would have dominated and driven the stabilizer to full AND deflection.

          • Rob,

            I’ll add one more point. My understanding is the MAX has Cat 3 ILS landing. How that is done without computers being able to move the elevators is beyond me.

          • Rob,
            My point and as I understand phillip’s is not a belief in EFS moving the elevator somehow. I emphasised what it does, as I recently learned via phillip’s earlier comments and confirmed in Mike’s link: “EFS module increases pressure to the elevator feel centring unit”. This is very clear language and leads no one to think EFS makes the elevator move. I may have earlier employed “actuated” too freely in this context, which in technical terms might be incorrect, I understand that. I assure you currently we are on the same page so far.

            From this misreading of my words on, you explain further facts which present no trouble to understand in my mind and still leaving us on the same page: MCAS’ purpose and what it does, AoA activation before Stall. You also present a conclusion of yours, which I am inclined to agree with for different reasons since it is logical, Boeing’s own in fact: the elevator is not capable to address the issue at stake – the pitch up tendency. But here it gets interesting, is it FEEL or is it STALL then:

            You mention force. Do you mean the force exerted BY the elevator reducing the pitch-up tendency OR do you mean the force exerted ON the column to prevent the pilot to move it aft and further risk high AoA? Because we both know that EFS works for the latter. And indeed this is what MCAS is claimed to do, work on the pilot’s FEEL, thereby admittedly addressing per Boeing, the certification requirement under such and such circumstances, or in JATR’s wording “used the stabilizer to change the column force feel”.

            This is the critical point, Boeing rejects employing the word STALL, preferring FEEL, on the other hand employs a more “powerful” control surface to achieve its end. Why couldn’t Boeing figure a way out of its problem using a tried, tested and certified way, ie. EFS? This is why phillip is wondering about the pressure on the hydraulic system: isn’t there a sufficient top psi to be increased to by the EFS to exert the required forces ON the column inhibiting pilot to further pitch-up risking getting into a stall? Maybe there is no compute budget available to deal with the non linear part of the force relaxing out of the column, maybe Boeing could not pre calculate a proper schedule for pressure increase. This is the problem Boeing implies it is addressing. But Boeing did not resort to this system, it opted for a moving stabiliser solution. But did Boeing rely on another certified system? No!

            Boeing left in place the Speed Trim System as is which already actuates the stabiliser and put it in conflict under certain regimes with the brand new MCAS. It also increased its power over the STS. Then eliminates one of the pilot’s fail-safe consisting of the column CUTOFF switch (This is getting serious no?). Then removes the CUTOFF switches split that existed in NG allowing the pilot to keep manual electric trim while deactivating the automatic one (WOW – this really must not be deactivated huh?). This is counter sensical or a VERTIGINOUS digress for an original control FEEL issue.

            Not happy with it, Boeing hides a relevant part of its tracks from the regulator (0.6 -> 2.5), removes information from the FCOM forgetting MCAS acronym behind and deprives pilots of appropriate training.

            Do you see Rob? The above are all established facts. I am sorry if, with bias one way or bias the other, which I certainly have, I have come to the conclusion that Boeing was not dealing with an occasional FEEL issue, there is something much stronger behind all these facts… perhaps a little s t a l l ?

            I’ll reiterate, and you will agree, we don’t and can’t know for sure because Boeing does not let us even access to clarifying data.

            And I know you know, there is plenty more irrational conduct by Boeing as a corporation, and its decision makers, to trade horizontally and vertically on this very instance before I even get emotional and all ranty.

          • Philip, as I understand it, the auto-land function is an extension of the autopilot. The autopilot does have access to the same control authority and surfaces as the pilot, including elevator.

            MCAS was designed for the case with autopilot not active. In that case, the pilot has full authority.

          • phillip, the 850 psi figure source applied to the NG. But there’s some relevant increase no doubt.

            EFS is not up to the task? Well then, what about a rescheduled STS, and if MCAS, why not properly integrated (or even moderated/bounded) by STS and its tried and tested reliable schedule and sensor input?

          • Rob,

            Thanks. We got there. I said computer not EFS. Going back, Richard restricted his comments to EFS. I agreed with his comments. I then said I would generalise. By that I meant beyond EFS.

          • Vasco and Philip,

            Great Work !!!

            What does this all mean for the NG?

          • Vasco, to clarify my position, I’m not saying that the elevator authority is insufficient in pitch. I’m saying that in an FBP system, the elevator authority is reserved for the pilot, as a design decision. And that this was a valid reason for Boeing to use the stabilizer as the control surface for MCAS.

            As far as whether MCAS is handling/feel system or stall prevention, that issue has been raised by many. It’s tricky because the non-linear portion of the pitch curve, which MCAS is meant to address, immediately precedes the stall portion. So if you handle the non-linear portion correctly, you are preventing stall, even though you’re doing it by modifying handling/feel.

            As I first learned about MCAS, I saw it as mainly preventing stall. Over time and after acquiring further knowledge and understanding, I came around to Bjorn’s viewpoint. I saw the goal of handling as being the more accurate description and intent.

            You’re suggesting that EFS could be used to limit elevator & pilot authority, by making the column too difficult to move. I think that gets clearly into stall prevention, but it has some issues. Unless it maps out the entire non-linear portion, you still have the handling problem. Also it limits pilot action but doesn’t correct for it, as a stick pusher might. Unless you want to have it push the stick too.

            As far as the column aft cutout switch, having that active for MCAS would defeat the purpose, as the pilot is pulling back on the column to create the A0A handling issue. So that removal makes sense. However Peter Lemme has pointed out that Boeing removed the aft cutout for MCAS, without removing it from the QRH or their assumptions for pilot response and safety assessments, even after Lion Air 610. So that shows Boeing still did not fully grasp the problem, and bungled that as well.

            As far as the alteration of the trim cutout switches, I agree that appears to have served no purpose. I’m sure Boeing did not anticipate the significance it would have, but there was a loss of functionality in return for no apparent benefit.

            The rest, as you said, is established fact, and no one is defending the mistakes that were made. I just think our purpose is best served by being as factual and accurate in our criticisms as possible, or in the alternate solutions we propose. I also think we shouldn’t make claims about Boeing’s intent, unless we have evidence to back them up.

            I know the DOJ is looking into possible criminal actions at Boeing. So we should let that play out to see if there is justification, before leveling accusations.

          • philip,
            The 850 psi figure is supposedly the maximum pressure available at feel control unit during stall, which is ~4 times the pressure out of stall (the minimum 200psi). The 3000 psi is the overall pressure of the system.

            Apparently the overall figures are similar. We don’t know the figure for MAX at the feel control unit.

            I began answering you, but missed the train, busy week. I am sure we will get to the these points opportunely.

      • Is the load on elevator to high? there are issues with 737 on to high load on frontwheel at rotation so there is somethinh here?

        Have Boeing stated that the nacille is actually causing the current stability issues? There is also a brand new wing…

        in case of nacille effects, bleed air for down wash assistance behind the enginne coukd perhaps be considered.

        The regulation does not prevent active systems for stability control, but then it is system must be regarded and evaluated as such

        • The elevator is not in question.

          The stabilizer was and is the issue both for MCAS and manual trim.

          The wing is not new.

        • RE VASCO de GAma

          ” This is why phillip is wondering about the pressure on the hydraulic system: isn’t there a sufficient top psi to be increased to by the EFS to exert the required forces ON the column inhibiting pilot to further pitch-up risking getting into a stall? ‘

          The stabilizer is moved by only two methods- one is the electric motor turning the jackscrew, and the other is by the manual- trim wheel to cable to drum thru gears to the jackscrew. NO hydraulics are involved re thye jackscrew. The Classic did use two hydraulic ” motors’ – but since the NG it has been by a single electric motor.

          Suggest you take a close look at satcom. guru for details.

          • Bubba, I think Vasco and Philip were discussing the case where the elevator was used to modify pitch behavior, rather than the stabilizer. The elevator & feel systems do use hydraulics. But you are correct in pointing out that the stabilizer does not.

          • Yes. As Rob said, we were mentioning Elevator Feel Shift EFS which use A or B hydraulics. Indeed Peter Lemme has been an invaluable resource.

  23. In November 2017, after several months of MAX deliveries, Boeing discovered that the disagree alert depended on the presence of the visual indicator software, a paid option that was not selected by most airlines. Boeing had determined that the defect was not critical to aircraft safety or operation, and an internal safety review board (SRB) corroborated Boeing’s prior assessment and its initial plan to update the aircraft in 2020. Boeing did not disclose the defect to the FAA until November 2018, in the wake of the Lion Air crash.

    • One that is nothing new and two unless you know about MCAS it does you no good.

  24. JakDak

    UA 232 centreline engine failure punctured all three hydraulic lines. My understanding is the positioning of the lines was less than ideal, to be polite to those who admire the DC10. They lost all controls. The pilots tried to fly the airplane using the engines. They came very close to achieving a miracle.

    It’s not the same, the changes of uncontained engine failure on a wing mount hitting all hydraulic lines is very, very small. It’s never happened on any airplane with wing mounted engines.

    The issue with the hydraulic lines on the DC10 is they all came together at the tail. Not a good idea.

    • Philip,

      UA232 was just the catalyst for trying to prevent accidents in the future, I understand how all the holes in the Swiss cheese lined up on UA232.

      “The F.A.A. engineers were particularly concerned about pieces hitting the cables that control the rudder, according to five people with knowledge of the matter and internal agency documents. A cable severed during takeoff would make it difficult for pilots to regain control, potentially bringing down the jet.”

      “F.A.A. managers conceded that the Max “does not meet” agency guidelines “for protecting flight controls,” according to an agency document. But in another document, they added that they had to consider whether any requested changes would interfere with Boeing’s timeline. The managers wrote that it would be “impractical at this late point in the program,” for the company to resolve the issue. Mr. Duven at the F.A.A. also said the decision was based on the safety record of the plane.”


      Initially reported at:

      “The panel cautioned against allowing Boeing to handle this kind of approval, saying “the company has a vested interest in minimizing costs and schedule impact.”

      What concerns me is “they had to consider whether any requested changes would interfere with Boeing’s timeline” so it appears the technical people say “that’s really not a good idea”, and they are then over-ruled by management.

      “the decision was based on the safety record of the plane.” based on the safety record of the NG, not the MAX, with different engines in a different location.

      It’s worth reading the NYT article.

      • It is but you also have to understand the US system, good and bad.

        FAA has a legal obligation to consider costs to implement a change on any aircraft (not just MAX or NG).

        Like any of it there is a political angle and public can drive the decision to implement it.

        • FAA may have legal obligation, but use of secret waivers to cover other issues doesnt go well with its other global certification partners

          Way back in a kinder gentler time , the costs were one of the reasons mandatory strengthened cockpit doors werent included after US planes started being hi jacked to Cuba ! in 1960s and 70s
          There were 130 or so US hijackings from 1961-69
          And this type of hijacking happened with stunning frequency in the United States. Between 1968 and 1972, more than 130 American airplanes were hijacked. Sometimes there was more than one hijacking on the same day. In a 2013 book, The Skies Belong to Us, Brendan I. Koerner, a contributing editor at Wired magazine, dubbed the period the “golden age of hijacking.”

          The hijackers, or “skyjackers,” wanted flights to communist Cuba, or millions of dollars in ransom, or maybe just an outlet for their rage and frustration. And for years, airlines largely gave in, fearing that customers would find metal detectors at the airport more off-putting than the possibility of a midair diversion.

          • And did Europe ( they really werent an EU at that time especially in aircraft certification) have around 130 skyjackings over a short period?
            I could understand ( a bit) why you wouldnt reinforce cockpit doors if you could count on one hand over a decade the skyjackings , but 130 ? Some days there were more than one. Hint Europe never had the US (hand) gun culture.

            Now the US has to reinforce the doors on classrooms !

  25. @Mathew
    “Okay, the F117 has ludicrous native aerodynamics taking a whole heap of “augmentation” (fine result too by all accounts), but someone at Lockheed decided it was necessary to do that 4 channel FCS in an aircraft with only one person on board. ”

    F117 had piss poor design.
    Look for MBB Lampyridiae : less facets but stable flight performance. Project terminated on US pressure.

  26. The FAA announced that it had withdrawn Boeing’s authority, previously held under the Organization Designation Authorization, to issue airworthiness certificates for individual new 737 MAX aircraft. After the overall grounding is lifted, the FAA will issue such certificates directly; aircraft already delivered to customers will not be affected.
    The FAA pushed back at Boeing’s attempts to publicize a certification date, saying the agency will take all the time it needs.

    • This may be related to the purchase clauses that Boeing could start collecting.

      No one was going to fly a MAX in commercial service until the AHJ of the country has agreed.

      note: Boeing and airlines have gotten approvals for waiver to move aircraft around with no passengers.

      • TW, just asking, if Boeing cannot issue airworthiness, does that mean delivery positioning of new planes cannot take place, or just that the AHJ has to approve each flight? Sorry, I don’t know how the process works.

        • This is new to me and as far as I know, has never occurred as it did not happen with high production aircraft like the MAX.

          My guess is that yes they can per-position .

          I personaly know of two waivers granted for really out of the ball park stuff.

          One was an MD-11 with a punctured fuel tank. Patch repair and they flew it South at no more than 10k allowed.

          The other was to put a 727 into Merrill Field AK so that it could be used for a engineer school test article. Field was too short and the weight limit into that field did not allow.

          Add in winter conditions and having to assess the braking surface.

          They setup a lot of conditions which were met and they did a bang on job.

          So I think they can get a waiver based on conditions being met. Exactly what would suffice is also a guess. Either Boeing test pilot or trained MCAS airline pilots would certainly be one.

          Special disable of MCAS maybe as well (software wipe or revert to original or closing the flaps switch circuit so it won’t activate)

          Also note Experimental aircraft are allowed to fly. Maybe even with the new software load.

          I have no issue with it as good pilots knowing about MCAS would likely trim and kill the stabs even if it did occur.

    • Does it fly under the FAA regs for passengers ? Would the pilots require special training ?

      • All Freighter aircraft meet the same specs as passenger.

        Crashing into a city can kill as many or more people

        And like Philip – you did not answer the question, is it stable or not?

        If a miner change can change the MAX into a ravening unstable beast then god knows what this kind of mod can do.

        • Im only thinking about the flying at the edges of the envelope and the pilots special knowledge ( they dont have to worry about having 9000 pilots with extra training like Southwest does )
          Guppies , Dreamlifters, those special 747s that carried the Space Shuttle are similar special types.
          It doesnt seem that maintaining the flying characteristics of the plane they are based on would be the way to go

    • Anyone actually reading it?

      There are a lot of questions I have and I am no where near done.

      He addresses a great deal of JTAR in it was well.

      Or is the object just to post rants and or cherry pick items and not get into those icky tech details and understand them that the world runs on?

      I had a lot of years of managers saying they did not want the details when in fact, it was the details that drove the decision one way or the other.

      Don’t understand it or don’t want to? Then you should let me make the decision because I do. (not all MCAS or JTAR, probably never will get all of it, super deep into the weeds but work at it and you can gain a working understanding)

      • TW, thank you for posting this, I did read it and am sure others will too. It informed the discussion with Philip and Vasco on EFS. It’s a huge amount of information, I cannot imagine the effort that Peter must have put into it. I’m still digesting it too.

        • Peter did but clearly he is deeply familiar with the subject so he does not have to learn the whole tech end!

          He writes well.

          Still chewing my way through.

  27. What’s going on with the 777x?Latest information(behind paywall apparently) is that the enormous fuselage rupture actually started at a passenger door frame.
    I wasn’t too concerned, but I’m am now. Why would Boeing lie? They told everyone that the 787 was almost ready, why does the city still trust them?

    • IMU, IMHO and all that Jazz:
      Boeing fibbed again and pimped the test by increasing fuselage pressure beyond test requirements (B best!) to fend off buckling.

      There was some Blowback 🙂
      Seems to be open what kind of fallout this will produce. Could be Zero. But going by quite visible Astro Turfer counter measures fear is strong.

      • Uwe

        It’s interesting, I would have thought you’d have cabin pressure at cruise altitude when doing the test, that is if you’re validating against your software model.

        “pressurized beyond normal levels to about 10 pounds per square inch”

        So what is normal then ?

        “Pressurization systems are designed to keep the interior cabin pressure between 12 and 11 psi at cruise altitude. On a typical flight, as the aircraft climbs to 36,000 feet, the interior of the plane “climbs” to between 6000-8000 feet.”

        From https://aerosavvy.com/aircraft-pressurization/

        Sea level atmospheric pressure is around 14.7 psi, so I’m really not sure what to make of Boeing’s test.

        If the cabin was at 10 psi, that’s roughly 10,000 feet, not what I would think BA are aiming for with the 777X, so if the reported figures are correct, that’s not good at all.


        • I guess I need to tell the TFH group that this was a fully instrumented and FAA observed test. Boeing may have done some stupid things but faking data or test parameters is not one of them.

          The A380 also failed its stress test, the wing broke at 147%

          While I was astonished that they did not make Airbus repeat the test, as usual, when you get the facts, it was a correct decisions.

          First its seriously close to pass even if it did fail and that confirms the engineering was very good.

          Engineering also predicted if it broke during the test it would break at that point. Beef it up, its not going to break elsewhere even with a bit of load shift and they put it into service.

          That is what I call an intelligent decision.

          While details are not forthcoming, Boeing was also very close under extreme test conditions that hopefully no 777x will ever see (or any other aircraft)

          Boeing obviously is not going to share anything at this point and I don’t blame them. Shot yourself in the foot on the MAX or not, its an internal issue.

          Equally obvious is that it won’t take much to adjust the structure to pass.

          Long term I would like to see if it was a predicted area of failure just for curiosity sake.

          • So why did they effectively lie about it? This is nothing like what they announced.Did they actually finish all the required tests before they wrote off the test fuselage?
            One possible explanation is that they leaked be picture now that they know that they have the situation covered but they have lost a lot of crediblity since the 787 launch plywood wing panel scam.

          • TW

            Yes if you’re just testing the wing breaking point, it’s close enough that they can feed into their computer models to verify their results.

            I suspect what has been reported is the difference in pressure;

            If the aircraft was at a cruise altitude of 35,000 feet, outside the pressure would be 3.46 psi, with a target for 777 cabin altitude at 8,000 – 10.9 psi so the difference would be 7.44 psi

            Assume now the 777X was at max altitude 43,100 feet around 2.35 psi, target cabin pressure 6,000 feet to compete with A380, 787, A350 – 11.8 the difference we get is 9.45 psi

            That would make a lot more sense !

            “We know the 777 fuselage, its structural qualities, and its fatigue margins really well,”


        • pressure differential is cabin altitude pressure minus atmospheric pressure at flight level
          6,000′ ~= 11.8psi
          45,000 ~= 2.1psi
          delta : 9.7psi

      • And what issues are applied to the 777x that fall under JTAR?

        I have and am reading both JTAR and Peter Lemme

        • 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.
          Aircraft functions should be assessed, not in an incremental and fragmented manner, but holistically at the aircraft level.

    • passenger door frame ?? Suggest you check source and date. I believe the seattle times made it clear the failure was at the aft Bottom edge of the wing ( wing box ) in compression buckling. The door ejection happened afterwords and was/is not considered to be a player in the failure. The real question is did it fail close to the predicted location. To determine ult failure with about 1 percent is outstanding.

      The basic 777 ult failure was in the wing, at predicted location, but at 154 percent or about 4 percent ABOVE predicted ultimate load. destruction is NOT a requirement, once you meet the 150 percent number for 3 seconds ..

  28. The strange story of the 777X cargo hatch popping out now has the appearance of an outright lie.Why would they do that?

  29. For the record on the 777x test, it was a fuselage, wing, and general structure ultimate load test (1.5 times the design flight limit load). It simulated flight loads of 3.75 g.

    Boeing also chose to pressurize the cabin during the test, which was not required but was viewed as a better test, since it would introduce hoop stress in the fuselage.

    The fuselage buckled and failed at 1.48 limit load, which was not a successful test but very close. There was secondary damage of the fuselage splitting open and passenger door coming off, mainly due to the pressurization. That damage was not relevant to the results of the test. The key failure was the buckling

    The area of the buckling will be reinforced, but probably not tested again, since it was within 1% of a successful test.

  30. Yes, the difference of 1.48 from the magic pass number of 1.5 is negligible.
    However I’m thinking a highly pressurised fuselage will maintain it’s shape better than one that’s not. And guess what Boeing has a nifty trick of reducing the ring frames web size near where passengers sit to get that elusive extra 2 in extra width each side. Having a discontinuity like that in what is normally a constant size frame could be raising issues of distortion…which gets us back to the unusual full pressurisation during the ultimate load test. I may be off track here , but I’m glad FAA was present to scrupulously check the results ….as they do.

  31. You do seem to be confirming that Boeing changed the test method,and made it inconsistent with previous tests even if it was more realistic.I think that the change would be more likely to produce a favorable result, although I’m not sure.I’m also not quite sure whether this could be described as “gaming”.
    Why didn’t they just tell the truth about the massive rupture if there is a completely reasonable explanation?Obviously massive failure is only to expected near the ultimate design load

    • Grubbie, I think first the rupture was not significant to the test, the buckling was the significant event. Also I think that they know the public reaction to those photos would be to focus on the damage rather than the test.

      For the F-35, an early test was done to measure & validate flight loads on the airframe. To make the test more realistic, they did combat maneuvers against an F-16. This was done with limits in place on the F-35 avionics, to avoid overstressing the airframe. The full capabilities are rolled out gradually so as not to risk the test pilot’s life.

      The test was successful in that the loads were as expected. But the reports in the media were that the F-35 was an inferior aircraft that could not even beat a much older F-16 fighter. This is the reality of the world today.

      In the past, journalists prided themselves on accuracy. Today, you just get the headline first, and you emphasize the parts of the story that will generate traffic. You can always print a retraction later, but often the damage is done by then, and may be lasting as well, since the majority of the public will not fact-check.

      • The real story of that F35 combat testing was different to what you suggest
        “When we did the first dogfight in January, they said, ‘you have no limits,’” says Nelson. “It was loads monitoring, so they could tell if we ever broke something. It was a confidence builder for the rest of the fleet because there is no real difference structurally between AF-2 and the rest of the airplanes.”
        AF-2 was the first F-35 to be flown to 9g+ and -3g, and to roll at design-load factor.”
        This was 2015 when the F35 ‘lost due to its low energy maneuverability against the F16.

        • Duke, from a later Aviation Week article that clarified somewhat:

          “However, the F-35 used was a flight test aircraft with a restricted flight envelope and lacked some features present on the operational aircraft.”

          I believe this is true because the block release at that time did not have the full flight envelope software. But I’m sure the F-35 pilots were permitted to use all the capabilities of their existing aircraft, as Nelson said.

          In general, the F-16 has ideal E-M characteristics, as it was designed specifically for that purpose. The F-35 cannot hope to compete on that basis, as it was not designed primarily for air combat. But the F-35 has extreme controlled high-alpha maneuverability, that the F-16 could not hope to emulate.

          So these are competing philosophies and advantages. In a close engagement of full-up F-35 and F-16, each pilot would try to use their respective advantage, and try to bug out if they could not.

          I guess my point was that the reporting has correct facts but lacks the ability to interpret them well.

      • Yeah but the truth eventually comes out and it looks worse than telling the truth in the first place. No one should imagine that anything bad about MAX handling characteristics or MCAS 2 won’t eventually become public knowledge as well.

  32. So it’s out of the realm to train pilots how to actually fly the stupid aircraft in high AoA and high thrust regimens, eh? As old fashioned a concept as it may seem to be these days, airmanship is underrated. Sigh.

  33. “Nov. 25, 2019, © Leeham News: Boeing still doesn’t have a timeline for recertification of the 737 MAX and the Federal Aviation Administration isn’t going to be rushed, but aerospace analysts are increasingly looking beyond the grounding at a normalized Boeing.”
    Well, I don’t suppose many folk expected it to be a year and 51 weeks to re-approval.

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