A Pilot’s Inside View Of Boeing’s MAX Response


“We were a little slow to take responsibility,” said Dennis Muilenburg, President and CEO for Boeing, at a two-day meetup between Boeing’s executives and a handful of industry influencers from across the globe I attended last week in Seattle.

Aircraft crashes rarely create mass panic. As rare as they have become, we still understand that accidents happen. The Boeing 737 MAX crashes were different. Members of the industry and the public instinctively understood something was awry—same operational phase, same aircraft, same pre-accident path, and same outcome.

To make matters worse, initial accident data revealed the treacherous role of a feature that was unknown to most before the first crash and barely explained before the second—MCAS, for Maneuvering Characteristics Augmentation System. Yet, Boeing and some authorities kept insisting that the aircraft was safe and should continue to fly until they got more data about what went wrong.

Can you imagine the authorities waiting for additional data before grounding more than 4000 aircraft after the second airplane crashed into the New York World Trade Center on Sept. 11, 2001?

Boeing and anyone else claiming “no problem” came across as out-of-touch with reality, deceitful and unconcerned with safety. The result is deep distrust.

Cheng Chi, a 737 pilot for XiamenAir who traveled from China to attend, mentioned that 70 to 80 percent of new Chinese pilots would prefer to fly an Airbus, if given a choice. Henry Harteveldt, principal at the Atmosphere Research Group, said that his group conducted research showing that less than 20 percent of airline passengers would definitely fly on the aircraft within six months of its return to service.

Boeing is aware and eager to tell its side of the MAX story but finds it hard to be heard after it lost much of its credibility. That is why its executives decided to reach out to us. Updating us on their efforts to improve the 737 MAX, return it to service, enhance its customer-care, reinvigorate its safety and quality culture, and regain public and industry’s trust seemed less their goal during the event than listening to what we had to say and ask.

As Muilenburg spoke, it became apparent that Boeing, as an organization, has a poignant sense of loss. When recalling his conversations with the family members of the deceased, he became visibly emotional, a far departure from his steely, stiff-upper-lip TV persona. “We take full responsibility,” he repeated several times. “We are sorry.”

Putting actions to words, Boeing has spent the last nine months examining what went wrong at multiple levels and taken steps to address it. It recently created a new Product and Services Safety organization tasked to unify safety-related responsibilities currently managed by teams across several Boeing business and operating units.

Furthermore, it is planning to expose its worldwide network of new and existing employees to the Everett-based Safety Promotion Center it set up a few years ago to foster a deep sense of awareness and responsibility among them. On the manufacturing side, employees have taken advantage of the reduced manufacturing workload to restructure and streamline the manufacturing processes.

So here we are, at the nine-month mark since the global grounding of the 737 MAX fleet. Snow is beginning to fall on the newly manufactured aircraft sitting in Moses Lake, Washington. As I write this, the MAX e-cab simulator equipped with the revised MCAS software and new cockpit warnings is humming with pilot workload CS25.1302 evaluations required for certification.

Recently revealed exchanges between officials suggested “no MCAS” as a way to return the aircraft to flight. That is not going to happen. Without MCAS, the 737 MAX cannot comply with Part 25 Certification Standards. More critically, without MCAS, the MAX is easier to stall inadvertently when the autopilot is off.

Initially, Boeing test pilots noticed that the need for back pressure to increase the pitch lessened—or the pitching rate increased despite incremental back pressure input—when hand flying approaches to accelerated stalls with the flaps up, especially with aft CG loading. Upon further testing, they noticed that the aircraft displayed similar, although less prominent, tendencies during approaches to unaccelerated stalls.

While this peculiar behavior observable on the pitch rate recording graph of the Boeing e-cab simulator points to a deteriorating lift-weight moment when approaching stalls, the aircraft continues to display positive longitudinal stability according to Craig Bomben, Boeing’s chief pilot, and will not pitch up on its own. It simply becomes less resistant to pitching up when nearing the stall angle of attack in specific aircraft configurations.

Part 25 regulations, not a need for feel similarity with the 737 NG, require a linear displacement for a given control force input to maintain handling predictability. For example, 10 pounds of back pressure yields 1 degree per minute of pitch change and 20 pounds yields 2. Thirty pounds for 3.5 or 30 pounds for 2.5 would disrupt the expectation and become unacceptable.

The role of MCAS is to adjust the stabilator as needed to restore the missing control resistance. The amount of trim applied varied between 0 and 2.5 originally and will continue to do so in the revised version as it stands today.

MCAS does serve a safety purpose. It helps pilots avoid over-controlling the aircraft into a full stall. That is why MCAS is here to stay and why flying the aircraft as it is currently built without MCAS would not be wise.

For the accident aircraft though, MCAS became a liability. The maximum trim down option (2.5 or half scale) was supposed to apply only when the aircraft was nearing a stall at extremely high angle of attack and low speed. However, the accident aircraft were flying at normal speed for the phase of flight when MCAS activated due to faulty sensor readings rendering the MCAS trim correction aerodynamically significant. The ensuing MCAS corrections meant to address the potential for secondary stalls aggravated the initial event.

Somehow, it seems that Boeing failed to consider this scenario in the original MCAS design—and nobody else caught it during the certification process. Most of the changes in the updated software version address the potential for erroneous MCAS triggers.

The new MCAS software will compare the data from both sensors, a feature that would have prevented the Lion Air crash. It will ignore sudden and near instantaneous dramatic increases in angle-of-attack values, a feature that would have prevented the Ethiopian Airlines crash. It will serve only one correction per excessive angle-of-attack trigger event, a feature that would have allowed both crews more time to troubleshoot while flying level instead of being repeatedly challenged by additional erroneous MCAS corrections.

Never fly the airplane with the trim. I am sure that every pilot remembers this basic pilot training mantra. Previous 737 design assumed that pilots would react to an unexpected pitch down moment the way they always had. They would pull back on the control column. Thus, all 737s, except for the 737 MAX, have a trim stop switch that interrupts a runaway trim event when pilots pull back the control column. MAX pilots should instead use electric trim to counter an undesired trim movement before shutting down the electric trim functionality with the Stab Trim Cutout, when appropriate. 

It should come as no surprise, then, that the Ethiopian Airlines crew choose to reestablish electrical trim functionality when they realized that they were unable to trim manually after shutting down the electric trim system as instructed in the Boeing procedure published after the Lion Air crash.

“We do not blame the pilots,” said Muilenburg. Nobody should. Given the scope of changes to the software, cockpit indications and training developed by Boeing in the aftermath, it is clear that erroneous MCAS activation was a confusing, treacherous and serious challenge to be met with a unique, precise and timely set of actions to avoid excessive tail loading and related control issues.

Proper knowledge and prior exposure in simulators equipped with MCAS functionality—something no commercial B737 Max simulators had at the time of the accidents—were essential to give 737 MAX pilots the tools they needed to handle erroneous MCAS activation. The accident crews did not have it.

Boeing appears committed to provide extensive levels of information and support to its customers and the public prior to return to service.

A fleet of Max simulators will be available. In addition, Boeing is aiming to adapt 737 NG simulators to simulate the MAX for airlines who already own 737 NG simulators and who are operating both types of aircraft. 

Back in March, I was halfway through my training to become an independent Air Canada 737 MAX instructor. I did complete all the ground-training modules, including the module about MCAS added after the Lion Air crash. The thoroughness and quality of the proposed MCAS training module Boeing allowed us to see this week is certainly far superior to the hurried and succinct details released in response to the first crash that left us with more questions than answers.

During the initial certification process, Boeing and the certification authorities overlooked potential scenarios. Murphy ’s Law applied. It is highly unlikely to happen the second time around. If the 737 MAX receives certification to fly again, it will be a sound aircraft and will come equipped with pilots trained to manage its caveats safely.

Mireille Goyer is a passionate aviation enthusiast, an airline transport pilot, a training expert, an author and an award-winning diversity and inclusion advocate. She has been an active member of the global pilot community since 1990.

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  1. An industry influencer is someone who is regarded as being in-the-know; someone who others in their industry look to for advice, knowledge and opinions.

    “a two-day meetup between Boeing’s executives and a handful of industry influencers from across the globe I attended last week in Seattle.”

    MS Goyer…a Chinese airline captain, Cheng Chi, a 737 pilot for XiamenAir, Henry Harteveldt, principal at the Atmosphere Research Group, and you are the only people identified as the “handful of industry influencers” attending this Seattle based meeting with Boeing executives including Mr Muilenburg…Boeing’s Gumby Damage Control One. A handful would not be very many names to include in your article.

    Mr. Chi, Mr. Harteveldt , and yourself, are not in my mind…industry influencers. Mr. Chi’s notable industry influencing statement ” that 70 to 80 percent of new Chinese pilots would prefer to fly an Airbus, if given a choice.”…followed by Mr. Harteveldt of the Atmosphere Research Group assertion that “his group conducted research showing that less than 20 percent of airline passengers would definitely fly on the aircraft within six months of its return to service.”, and your incredible comparison of the two MAX crashes with 9/11 to make a point of Boeing’s initial claim of still safe to fly by this comment…”Can you imagine the authorities waiting for additional data before grounding more than 4000 aircraft after the second airplane crashed into the New York World Trade Center on Sept. 11, 2001? ” has completely destroyed any credibility I have with you, your claim of these folks as industry influencers (Mr.Chi and Mr. Hartveldt…really???…is this the best we have for industry influencers???), and the purpose for this previously unknown meeting with Boeing.

    This blog has further reinforced my ever growing skepticism of the effort Boeing and it’s cadre of damage control lawyers is stooping to get some sort of sympathy?, empathy?, compassion? from the within aviation community for what end or purpose?

    Using “”As Muilenburg spoke, it became apparent that Boeing, as an organization, has a poignant sense of loss. When recalling his conversations with the family members of the deceased, he became visibly emotional, a far departure from his steely, stiff-upper-lip TV persona. “We take full responsibility,” he repeated several times. “We are sorry.”” Is this supposed to emotionally move me? How sophomoric. As far as Mr Chi is concerned, his ” industry influencing” statement, given a choice 70-80% of the Chinese airline pilots would rather fly an Airbus is asinine at best. An incredulous statement to be made at a meeting with top Boeing brass which shows not even a smidgen of common sense let alone decorum. Does any airline pilot have the option to say when assigned his flight…Sorry, today I would like an A320 rather than this Boeing…really MS Goyer? And Mr. Hartveldt’s research about only 20% of the passengers will fly on MAX within the first six months of return to service. Are you kidding me? I hate flying on a CRJ. However, unless I found another way to my recent Florida destination, my only choice was a CRJ…take it or leave it. I know what a CRJ is mostly because I am in the aviation industry. The largest percentage of today’s passengers would not even know the difference between a 737NG, 737 800/900 MAX, or the original 737 designed in the early sixties. ( Go ahead, ask me where I got my research from to make that statement…maybe I can become an “industry influencer” and sit in as an expert having a chat with Mr. Muilenburg). For that matter, most would not know…or care…if what they are flying is called a CRJ, DC-3, or a DeHavilland Comet…as long as it has an overhead big enough to stuff a suitcase that belongs in the baggage compartment, looks like an airliner, has an internet connection, with a flight attendant or two on board, they will fly in it. I am pretty sure the airlines currently flying MAX will NOT have MAX painted anywhere on their airplanes. ( Ask me where I got that research from, too).

    “Never fly the airplane with the trim.” Have you ever flown a Saratoga, a Bonanza, a King Air, maybe my hated CRJ without trimming…continually trimming for take-off, cruise, and landing? As and “industry influencer” you are really making me nervous having an ATP and making your quoted statement.

    “Previous 737 design assumed that pilots would react to an unexpected pitch down moment the way they always had. They would pull back on the control column.” What in the world do you think they initially did? They pulled back on the yoke and MCAS pushed the nose back down. They pulled back on the yoke, tried to trim with the electric trim, and MCAS further pushed the nose down. In both crashes, they did what just about all pilots would do and tried with all their might to pull back on the stick, tried re-trimming in the way they knew, tried all sorts of things good and bad…and went virtually straight in. They did not react as Boeing MCAS engineering thought they would. Unfortunately, neither did these two MAX aircraft either. But to say, the pilots of these two fatal accident airplanes did not pull back on the yoke as expected, makes me cringe when I see your statement being an independent Air Canada MAX instructor. I wonder what you would have done differently had you been in the cockpit of either of accident airplanes. But I would bet a huge amount of money, you would have pulled back on the stick with all your might if faced with a windshield of water or earth forced upon you because of a an unknown ( to you) component on board the airplane you had been assigned to fly.

    The remainder of your scattered points are only more cannon fodder for your bizarre blog.

    You have given me great pause about your credentials as a pilot, training expert, but certainly reinforced your bio being an award winning diversity and inclusion advocate. Let me know how Captain Chi fares when he asks for an Airbus in lieu of a Boeing. I am sure being part of the flying non-trimming global pilot community you and Captain Chi will be “industry influencers” staying in touch to “influence aviation industry”.

  2. Dear Jim, being one of the blessed individuals who have written for and follows this blog section of AVweb, I’d ask you to tone it down a tiny little bit. One could indeed begin to think that you get into some sort of distress-mode, when women get involved. Man, I am glad Ms. Goyer is not a Chinese woman and god help her if she sports any tattoos. Women do have a right to have an opinion and share it with fellow aviators, you know?

    Companies frequently turn to writers and journalists for “good press” and “influencing” or persuading public opinion on matters of much less significance. Good influencers just never “identify” as influencers, they actually influence others to think differently or deeper about narrative- stricken subject matters.

    When I read Ms. Goyer’s blog (which is OPINION), I do feel as if there is a certain spin – however I also know that Paul Bertorelli is the final authority on releasing it or not. I have written and submitted some hilariously biased blogs, that came flying back with a (probably) profanity- grumbling Paul wondering why the bleep he ever invited me to write a blog in the first place. I opt to take the guidance and try to do better. A LOT of people read what is written here, just a few understand that blogs are NOT news. By all definition, we should engage the blog as what it is (OPINION) while noting that it passed Paul’s sniff-test.

    Of course Boeing is on the hook and every person with half a brain is capable of following congressional hearings and compare and contrast the various news narratives being presented. Having intellectually evolved (supposedly) homo sapient should be also capable to know that what is going on currently, has a very political after-taste. A bunch of turds in suits which (by and large) could not tell the front end of a 737MAX from a hole in the wall, are asking our current FAA Administrator questions about what happened and to quickly fix it. Jesus! Nothing is quick in aviation! One side bitches about Boeing being a FOR PROFIT company, while others bark that Boeing should be able to go full capitalism and do whatever they dream up. A ginormous mix-up of regulatory insanity, paired with the certifying authority handing control back to the manufacturer – thereby essentially allowing Boeing to self-certify – with the FAA being in no shape to even remotely comprehend all the nitty-gritty details, much less come to confirming regulatory compliance conclusions. In my opinion (its simple) SHTF and a system bound to fail, finally failed, costing hundreds of people their life and likely thousands of others the loss of a loved one. It also caused severe damage, financially. As we all know, investors and shareholders are holy, much holier than normal people. A public relations nightmare of dreams, for someone like me.

    Maybe Boeing is tired of the narrative which is spun – maybe Boeing doesn’t feel as if it’s voice is heard? What are their options? Turn to a journalist and that publication will be declared fake news, turn to congress and be taken apart like a middle aged drug addicted pedophile who was caught with the hand in the cookie jar, turn inside and see retired whistle-blowers speak up in public, even though whistle-blowers are just about untouchable in other circumstances, no matter which narrative they serve?

    My eyes are squarely on Stephen Dickson. Not because he’s a Trump appointee, but because he’s a pilot who seems to have taken this dilemma on as his own. FAA subject matter experts where told to take ANY time they need to get to the very bottom of it, prior to putting a stamp of approval on it. I assume Dickson is not naive enough, to skip asking a whole bunch of MAX and 737 pilots and instructors for their expertise, prior to making that decision.

    At the current time, I would not ask anyone at Boeing HQ what time it is, without having access to an atomic clock controlled by Vladimir Putin himself. This should have never ever happened and I ding both, Boeing and the FAA for failing to ground these aircraft, just a minute after the second crash became known. This stunk to high heaven, right from the get go.

    If we try to certify an airplane based on the regulatory frame of a predecessor aircraft, we better make sure that airplane employs the same damn characteristics and behavior as it did in the past. If it doesn’t, we need to tell the pilots, who are supposed to manage the box in day to day operations, that the plane will show an “off the grid response” to certain actions. Heaven knows we have basic stick and rudder-skill issues in our current set-up, but when I sit there, dumb, fat and happy and I want my stupid airplane to go anywhere else than the computer thinks it should be going, I demand full and unlimited control. If you say I can’t have that, fly the damn plane yourself. Way in the beginning of this debacle, someone we don’t speak of said: “Maybe we have too much automation, maybe we shouldn’t have so much automation, I mean it’s incredible, have you seen how much automation is in, and I mean it’s ridiculous!” (Not an ad verbatim quote, but I liked it, because, me thinks he was right.)

  3. A note here about commenting rules and expectations. While we welcome opinions of all ilks, this is still a moderated space. We ask that you maintain a civil tone in all comments and refrain from personal attacks and name calling. I don’t relish deleting comments or turning off the option, but do ask that you treat authors and fellow commenters with respect.


    Paul Bertorelli

  4. As concerning as the MAX saga is, the slat-track incident is far more concerning to me. ANY knowing act of non-compliance should be disqualifying. Period.

    IMWO, a top-to-bottom review of Boeing’s Quality Culture is in order. Increasingly, it looks like the problem is not the airplanes; it is the company. Heartbreaking. And frightening. Danger, Will Robinson.

  5. Criticism accepted. My apologies to MS Goyer for going over the line in my response to her article. Looking over my response this morning, indeed it was disrespectful. Once again, my apologies.

    • Apologies accepted, Jim. I responded to Boeing’s invitation, regardless of my personal perceptions and assumptions, because I believe everyone deserves to be heard without a filter. Let’s stick to discussing facts and ideas so we can all learn and grow.
      Please note that Captain Cheng Chi likes flying Boeing aircraft, as did his father. His statement reflects how Boeing is perceived by new airline pilots in China and the extent of brand reputation damage. It was, in my humble opinion, worth noting.

  6. I recognize the importance of Boeing in the economy and aviation and the many contributions to the aeronautical trades. I wish Boeing the best. BUT, after the MAX “accidents” appearing to be a consequence from bad management and bad product design – Boeing needs to clean up their act. Dennis Muilenber’s comment “… little slow to take responsibility,” will NOT bring back to life 357 souls. His attempted apology does not suffice. My impression is that the Boeing product has lost immense trust worldwide. The MAX series reminds of the 1960s Chevy Convair. Tough hole to climb out of.

    • Raf:
      I’m going to presume that you meant the 1960s Chevrolet Corvair. (Convair made airplanes.)

      IMWO, the much-maligned Corvair was one of the nicest little cars (a Monza 990 convertable, in my case) that I ever drove back then. Fond memories of 1960s fun!

      And a mich better car than Chevy’s 1970s Vega. (Uggh!)

      As for people’s trust in Boeing… it’s low, and declining each day. I can’t help but suspect that it was a factor in Quantas’ selection of the A-350 over the B-787.

    • Raf,
      Good analogy.
      Both had their minor foibles that were easily managed by company people in the left seat.
      Both will never recover from the scathing bad press they received from non-technical writers.

      Personally I still drive a sports cars from that era with the semi-trailing arm IRS. It is perfectly fine as long as you understand the geometry and physics of what you are operating. If you drive it abruptly or stupidly, it will bite you. If you drive it smoothly and knowing the foibles, it’s an SCCA champion.

  7. Thanks Captain Goyer for saying what a lot of us have been thinking, but couldn’t prove, the 737MAX is uncertifyable without MCAS, a fact Boeing left out of the pilot manual, and never told the FAA.

    • Everyone who has followed this saga (including the FAA) knows that the MCAS is a certification-rules-compliance measure.

      • Everyone may have known, but Boeing never admitted that the MAX was uncertifiable without MCAS. I wonder, was this secretive system even listed in the MEL? Was Boeing willing to allow dispatch with MCAS inop?
        Can any MAX pilots or mechanics answer that?
        Another question is why did Boeing remove the stab trim mechanical brake? It would have saved those two planes that crashed.

        • You don’t have to “admit” what everyone knows. This is about incompetence; not treachery.
          The slat tracks fiasco is about treachery.

  8. “That is why MCAS is here to stay and why flying the aircraft as it is currently built without MCAS would not be wise”
    The Author explains that the Stick Force Gradient on the MAX is not acceptable.
    The reason, is that the larger further forward engines provide more horizontal area forward, causing lift at higher angles of attack.
    The normal fix for such a problem would be to add more horizontal area aft; a larger horizontal stabiliser.
    That would have cost money and time; things Boeing wished to avoid.
    So; a Kluge call MCAS was installed; hurriedly and poorly thought out, a true Kluge.
    A larger horizontal stabiliser would have been cheaper than the mess this has landed Boeing in.
    It would also have had no failure mode like the MCAS. It would just have been there for the life of the aircraft.
    With 26000 hours, much of it instructing on Boeing, Douglas, Airbus, DeHavilland, and others, I have seen a lot of nonsense and a lot of good design work from the companies and their engineers.
    This was a stupid solution to a basic aerodynamic flaw; people died.

    • As long as MCAS exists, the MAX disasters will never be forgotten. That will not bode well for Boeing I don’t care how well the new and improved MCAS works. All of Boeing will forever be affected in a very bad way. The long term costs will not be realized for decades.
      It would be wise for Boeing to completely get rid of MCAS and design a tail section that completely satisfy’s the original design. Trying to fix MCAS is just throwing good money after bad and no one will ever forget the original MCAS.

  9. Read article and all comments.
    Agree with Jim H, no real need to tone it down as per Jason’s comments IMHO.
    In the 737 MAX, Boeing has built an unstable airplane and fixed it with software instead of redesigning the tail/airframe, because that fix was faster and cheaper by far.
    After reluctantly and only slowly recognising the problem (hubris), Boeing is now pushing for sim and training as the fix (plus a few tweaks to the MCAS), because that is still way cheaper than redesigning the tail/airframe (more hubris).
    In other words, its trying to push a substandard fix onto us while avoiding the root problem. Still hubris.
    In my book, that wont fly. Sorry Boeing, you are going to have to go back to the drawing board before me and my family will fly in a 737 Max.

  10. Correct me if I am wrong but aren’t most of the top management of Boeing came from McDonnell-Douglas buyout? This entire MAX situation seems reminiscent of the MD11, and all of the aerodynamic compromises made with that airplane. How many of those planes have crashed over the years and the FAA still allows it to fly. I agree with Tom C. The tail needs a redesign to correct the instability the MAX has now.

    • A tail re-design? Given all of the consequences that would bring, they’d be better off hanging new engines on the 757.