737 Max Update 29 April 2019 'The Cost'

[@bwinsky]

For the CEO to defend the single AOA as, “we followed the process” is indefensible and the board should ask him to resign.

[@GH-oi2jf]

Bill Winsky - If that’s what he said, it’s a broken process and it needs to be repaired.

[@shoersa]

@@GH-oi2jf Exact same thought came to me the minute I heard “we followed the process”. If they followed a process and it produced the original MCAS system with a single AOA sensor & no redundancy then logically the process is truly broken & needs to be trashed and a new better process put up in its place. Not only do they have a flawed MCAS system, but also a flawed process!

[@In0vat0r]

Bill - The real problem is that the "single AoA" claim doesn't stand up to scrutiny. The 737 MAX's stall identification and management system is fully redundant. The two AoA's connect directly to tow different Stall Management Yaw Damper computers, each of which individually drives a Control Yoke Stick Shaker on the same side of the cockpit as the Angle of Attack sensor. The story about there being a Single Point of Failure originated with the Seattle Times and has no basis in fact. The block diagrams and schematics from the 737 Flight Operations Manuals and explanations of how MCAS works, as early as January 2017, in the 737-7/-8 System Differences Training Manual (Volume 1, page 748) tell a very different story.

[@bwinsky]

Dexter Francis - What you are saying is misleading. It may be true that there are two autopilot systems, 1 for the pilot and 1 for the copilot, each of those autopilot MCAS systems rely on 1 AOA sensor, albeit a different one. Secondly, you reference this being documented in the flight operations manuals, yet all pilots say there was no notifications to them regarding MCAS. Certainly there were no procedures to switch to the other autopilot and therefore the other AOA sensor.

[@In0vat0r]

@@bwinsky - I don't know how many 737 Type rated commercial pilots there are in the world. What I do know is that saying that "all pilots" say there was no notification to them is misleading. Information about MCAS was published by Boeing in Volume 1 of the Boeing 737-7/-8 System Differences Training Manual, on page 748 in January of 2017. Even the Seattle paper reported last November that not all pilots are on the same page with regard to MCAS. (www.seattletimes.com/business/boeing-aerospace/dispute-arises-among-u-s-pilots-on-boeing-737-max-system-linked-to-lion-air-crash/) With regard to there being no procedures to switch to the other autopilot, that is wrong on two counts; First is the necessity to do that in the first place. The redundant paths are to the stall warnings, which are the stall shakers. Second is your comment that "Certainly there were no procedures to switch to the other autopilot and therefore the other AOA sensor." The procedure to "switch" to the other autopilot a.k.a Flight Control Computer (which was functional and providing accurate speed altitude, pitch roll and yaw information to the Electronic Display Unit on the co-pilot's side) was, and is, simple; Pass control of the aircraft to the First Officer and let him manage the pitch and airspeed while the Captain runs thru the abnormal procedures for a Runaway Stabilizer condition - which is what the situation would have looked like to the crew. That condition was probably recognized by the First Officer as he called out "STAB TRIM CUTOUT" twice at 05:40:35Z - two and a half minutes after takeoff. Unfortunately, by then the aircraft was flying too fast for manual trimming of the horizontal stabilizer, as someone had forgotten to pull the throttles back from full takeoff power. I suspect that the Captain was reluctant to turn control over the F/O since he only had 361 hours of total fight experience and 57 in the MAX 8. It was admittedly a difficult and ultimately tragic situation, The experienced pilot has bad flight data on his display. The inexperienced co-pilot has good information on his. It was a classic Crew Resource Management scenario.

[@NewChapterInCebu]

I am recently retired automation engineer, with some aerospace experience (757) and lots of power industry experience. This channel is by far the best source of information I've seen for this 737 Max issue. Keep up the good work.

[@alexp3752]

Years ago, I was an airline VP who actually bought our aircraft from Douglas and Boeing. I supervised the production process, QC, flight test and delivery. In my opinion, Boeing should have not placed the larger engines on the airframe without extensive design changes. This would allow longer main landing gear to provide proper ground clearance. Weight, balance and thrust concerns may have also played a significant role and wing placement as well. . The costs involved would have been huge, but that's life! The 737 has been a real workhorse. Back in 1969, I flew on LH with a 100 series with the low slung, P& W engines. The problem is that Boeing did not make the needed landing gear and wing box changes to allow it to use larger powerplants. In my personal opinion, I don't like any critical flight control surface actuation not under the direct control of the pilots, namely computer control. Having full control surface authority is a big selling point for American aircraft. It is more than sad that hundreds lost their lives in accidents that should have never had happened. The airline and airplane business is unique in that those who fail to embrace safety above all, soon find themselves out of the industry. Safety has always been a paramount concern for those who design and build commercial aircraft. I cannot imagine the toll this has taken on the valiant men and women of Boeing as well.

[@ahungryflyer]

Your videos on the MAXs have been invaluable juan. No sensational BS, no speculation, just technical information relayed in an easy to understand manner. Looking forward to a long and distinguished career of safe flying for the MAX series of airplanes once they return to service.

[@1973mre]

Thank you so much for doing this update. You got this out quicker than I expected after sending you a question today on your last video. It’s nice to hear somebody who reports the news with knowledge behind what they are saying. Listening to the mainstream media grill the CEO today with no education of what they’re asking. Thanks again, I’m glad you’re following this I always did enjoy the Oroville updates.

[@bruceavis1610]

The CEO won`t admit liability because of ongoing suits, his responses reflected that.This could cost a whole lot more than they think as airlines world wide consider cancelling orders.The aircraft may well be safe and inherently stable but the public perception is that it is not ... and perception can be a difficult thing to change. Thanks for the facts and interesting stuff on other Boeing aircraft as well.

[@blancolirio]

Exactly.

[@Phantoman]

@@blancolirio Yup, they need to pay attention to Trump's advice. Perhaps rebrand it as the 737 Don instead of Max? Great video!

[@ReflectedMiles]

And so Boeing's legal team should then go after every source of misinformation they can identify that created and/or broadcast the false information on which that perception is based, particularly after all of the details and analyses of the two accidents are released. If it is time for Boeing to be held accountable, it is long past time that the media are held accountable for the ignorant, sensationalist swill that they pump into the brains of the public every day.

[@Rickie53]

All of your 737 Max update videos have been the best explanations of the incidents that occured, the reasons why they seem to have occured, and what will most likely be done to remedy it. Keep it up

[@timblaker7138]

Juan, in the news business there is a saying to obtain viewer ratings: " If It Bleeds, It Leads." Thank you for your unwavering adherence to truth and facts in your reporting.

[@Markle2k]

Another way to put that is "If it involves the loss of human life, we consider it important to bring it to your attention."

[@swarfrat311]

Thanks for the update, Juan. An old saying comes to mind: "Penny wise; pound foolish."

[@Rwalt61]

It's beginning to be that when watching and waiting for info on the 737 MAX I watch this channel and Mentour aviation instead of mainstream media.

[@chumanho]

Good call!

[@tomrodgers1578]

Amen to that!

[@COIcultist]

Why would you ever watch MSM with regards to this? If you ever look at a technical issue that you have knowledge of MSM invariably fails to understand at least one part of the story. MSM has too much become agenda led, blending a selection of facts and or half truths into whatever storyline that it wishes to pursue. Politicians seem in fear of "Fake" news whereas MSM is the real fake news. Politicians real fear is that they don't know who to brown nose to any more!

[@markg7963]

I pay no attention to any kind of media, have not for years.... 5% facts and 95% speculation, 100% attempt at drama for advertising and spin factor. You can pick out the 5% facts when u are an expert on something, but the rest of the time you can’t, and therefore are just being manipulated. Juan does a great job, and understands how to give the facts as they specifically relate to his area of expertise. Making him better than any other media outlet I’ve seen. By a long shot....

[@johnnyboythepilot4098]

Plus the MSM simply has a pretty bad reputation in the aviation community for almost always getting their aviation facts wrong.

[@humanonearth1]

Typical CEO lawyer speak. He's worried about all the lawsuits. A flight critical system with massive pitch authority has zero sensor redundancy, no command limit, long execution time, and upon failure there is no way to control electric trim (a very significant change from the NG, which pilots didn't know about either). If that's not flawed they have a very very low bar for soundness.

[@andyhampsten4252]

Finally someone who gets it. The aircraft is stable but the implementation of MCAS is unnecessarily dangerous. Just watch Juan's episode describing the fix.

[@johnfrancisdoe1563]

Thomas Headley The necessary retrofit on each aircraft, for a proper fix, would be software and some wiring changes. All small enough to have Boeing's repair crews fly from airport to airport with a suitcase of tools and parts. Even 737MAX-es grounded in airports without service facilities should be fixable there. The fixes beyond the proposed software patches, that would make sense are: 1. Restore the 737NG wiring and labeling of the two cutout switches, and tell pilots which one isolates runaway software while keeping the trim buttons. 2. Improve AoA wiring and ADIRU + FCC input circuits to detect broken wires and AoA internal error reports. The cos+sin signalling scheme has room for detecting invalid signals not corresponding to any possible angle, and an upgraded FCC, ADIRU etc. should report this as "no signal" instead of a wrong angle. Test by artificially disconnecting or shorting AoA wires and checking correct error indications. 3. Maybe get Rosemont to improve internal error detection and reporting in their AoA sensors via a firmware update. The improved sensors would still fit all the existing aircraft, only with less tendency to trigger failures such as incorrect stick shaker.

[@humanonearth1]

@Thomas Headley Perhaps, but the economic forces involved are less important that the safety considerations. This is at the crux of the entire industry and matter.

[@mbonje4948]

The 737 max, because of the placement of big engines, has a tendency to raise it's nose under certain power settings and possibly end up in a stall. At least that's what I thought we were told over the past 4 weeks. The MCAS system corrects this by lowering the nose behind the scenes. In other words an aerodynamic design challenge was solved through software. To me it seems the plane is inherently unstable, it it was stable like it's earlier generations, there wouldn't be a need for MCAS

[@GH-oi2jf]

Abisai Mushaka - Every aircraft with engines slung under the wings, below the center of mass, has a pitch-up moment under power.

[@2adamast]

The problem is not new for the 737, what's new are those big engine in front of the wing. I think the no flaps full power stall characteristics of the 737 max are very spectacular.

[@vladimir0rus]

@@GH-oi2jf but MAX engines might work as wing, that's the problem and cause of instability.

[@bloodguard41]

Juan has explained concisely what the issue is in this video and the previous one, as well. Plus, in the previous video, he posted a link to an article which describes tests done by pilots who then commented on the plane's "lack of stability". But, I guess if that wasn't enough for people to get the picture, nothing will be.

[@GH-oi2jf]

Владимир Кузнецов - It is not instability. Whatever the pitch contribution from the engines, either from thrust or from lift, it can be counterbalanced by adjusting (trimming) the horizontal stabilizer. All aircraft use trim to balance the pitch forces. The need to do this is not properly called an instability. MCAS is used in the Max to make the handling characteristics similar to the NG by automatically adjusting the trim in certain situations. Without MCAS, pilots would just do it themselves.

[@yippie21]

Good stuff Juan. Well explained . I hope Boeing PR folks recognize the value of having you come in and fly the patch.

[@sarowie]

From what I understand, MCAS is supposed to only deliver limited trim input in specific situations and it has done so reliably for many years and flights. (Except when the AOA sensor malfunctions) So... I see little point in him testing the new system. As a 737 type rated pilot he should literally not even realize that MCAS is intervening. Boeing would have to stage a situation where MCAS actives and then in the flight review highlight where MCAS has activated and all Juan should be so say is, that he did not "feel" it while flying and it feeled like any 737 - which given that most 737 Max 8 pilots did not get 737 Max 8 sim training before first flying a 737 Max 8 already with the old MCAS has to be the case. So, what is the point? He as a 737 rated pilot can fly a 737 Max 8 with minimal training? Big deal, every 737 Max 8 pilot still alive can attest that. What would be interesting is a system malfunction - but I doubt that boeing would setup such a session.

[@lylestavast7652]

@@sarowie It's amazing what you can get done once you've signed up as a friendly with the right NDAs ;)

[@joemeyer6876]

Having been a QA and Customer Coordinator on the B-787, for five years, I can assure you that the “software fix” has been incorporated into every B-737 coming off the production line, and retrofitted on every completed jet they have stashed in every corner of Renton, BEFORE Certification by the FAA! This ‘cart before horse’ mentality is what pissed me off about Boeing Processes! I’m sure that there is a team, more than one team out there, frantically rewiring AOA vanes and loading software on 737 Maxes, BEFORE any ink is placed on a design revision by the FAA. I’ve been retired since 2013 and I won’t ride in a Max. Why? Because the flying public is being told it’s just an isolated MCAS issue, when it’s really an issue of slapping overpowered and oversized engines on an airframe that can’t handle it aerodynamically. Single Engine VMCA and MCAS, next Oprah! I love your channel Mr Brown, go fly that Sim.

[@henson2k]

Thank you for valuable insight

[@JoeLinux2000]

If Juan does get his simulator ride, I'd like to see him take off and land in turbulent weather with no operational MCAS system so we can lean just how easy it is to fly the MAX without the MCAS.

[@bloodguard41]

@@JoeLinux2000 I would think that, in nearly a year and a half of the plane being in service around the world, prior to the first accident, there had been plenty takeoffs and landings in adverse weather conditions.

[@rhamph]

@@JoeLinux2000 MCAS never activates during normal operation. It only activates if the plane is already at the limit of the operational envelope, nearing a stall. Every other plane has the same risk of stalling if the envelope is exceeded, the MAX just has a slightly smaller envelope than the other planes *of its type rating*. Other planes of different type rating may have even smaller envelopes, but as they do not share type rating the pilots can be trained directly to expect it and it's completely fine.

[@darrenedmonds2818]

Love your input - i knew the "pretty and the vacant" had taken over from the human beings that know instinctively what to do. This is a good thing in that this issue is a platform to not only take over boeing from the demons - the whole world from the demons that wish to destroy humanity and take our planet for themselves

[@syx3s]

hey juan. this is the fastest i've ever clicked on a video. you're information presentation is exactly what we want. thanks man, and i hope youtube is making it worth your time because this is some of the best news content they've got.

[@4FOGIDNI]

W. McMaster I purposely ignore all “news” companies reports on the Boeing situation and wait patiently for Juan’s videos. Straight to the point from a real pilot without the fancy bs and speculation! Thanks Juan!

[@dieseljo2]

I could not agree more with Mr McMaster... Juan update = must click on asap. Thank you!

[@shawnstanger820]

@@dieseljo2 respect

[@esarlls3]

The original MCAS was flawed because it did not respond safety to simple instrumentation failure modes. I understand their insistence that it's background (to avoid the customer cost of additional pilot training), and that it was not flawed (to reduce liability). I don't think that will fly with airlines, regulators, pilots, or passengers. The shortcut to getting back in the air is accepting responsibility. Without that, what else might be lurking in systems that were not well tested?

[@esarlls3]

I would add that an AOA Disagree notice is good but an AOA Disagree should also automatically disable AOA based controls. roguerocket.com/2019/05/06/boeing-knew-about-max-8-problems-before-crashes/

[@wdonno]

Re your point: MCAS was implemented to maintain the type rating. That was inherently a commercially driven decision. It sounds like that commercial overtone cascaded through its development cycle, even to the extent of deactivating the "AOA sensor [disagreement] light". Not a good look.

[@chumanho]

So it look like the MCAS isn't even necessary provided that the pilots be retrained for the 737 MAX, but we all know that training pilots cost money. *sigh*

[@eccosabanovic1589]

...what about fact that airplane goes in to stall, when pilots throttle it up ? In some previous videos, that was mentioned as a reason, not just 'type rating'..Bloody thing is it fault by itself.

[@gbnq2513]

The point here with Boeing is that the 'base' model Max aircraft came without dual AoA instrument comparison with display readouts plus an AoA disagreement light and appropriate warning alarm. These three 'items' came as part of an optional upgrade - i.e. Boeing monetized a safety feature. So. If they sold the aircraft without the package and considered the aircraft safe enough, then why would anyone want to pay for an 'optional' extra that was not necessary ( Ethiopian and Lion did not buy the optional package)? Or conversely, if the optional package makes the plane safer, then why would Boeing sell the aircraft minus a safety feature - selling a less safe aircraft? The question to ask is, would the outcome of those 2 flights have been different if the pilots of the aircraft had the 'optional' package installed aboard? Obviously yes, Boeing thinks so. Because this is basically what Boeing is doing now as remediation to get the 737 Max back in the air - They are adding what was in the optional package ( dual AoA instrument comparison with display readouts plus an AoA disagreement light and appropriate warning alarm). By adding in these things that Boeing sold as 'optional' to now get the aircraft safe and cleared to fly again would suggest that these items should have been on ALL the aircraft from the start, not sold as some 'optional' upgrade that wasn't really necessary. Lawyers are going to have a field day with this one.

[@wdonno]

@@gbnq2513 could not agree more. Then, step back up the accident chain:. To have a safety critical system driven in real time by a single sensor and with inadequate software control (not even checking the input is within the flight envelope?) you start to see a pervasive pattern of non compliance with reg requirements and perhaps even willful negligence.

[@Wilhelm5381]

it is criminal that Boeing didn't inform pilots that MCAS was on board; Boeing's corporate culture must be dreadful.

[@frantucker608]

If anyone can get through to them, Juan, it's you! We await your results. :)

[@brettlw2]

Juan, I really appreciate your updates. I wanted to get my license back in 82. Had about 7.5 Hrs of flight time and couldn't afford it after that. But I try to kept up on things. Your explanation of Mcast was easy to understand and informative. Thanks

[@REDMAN298]

@@brettlw2 Mcast????? Get it right. theaircurrent.com/aviation-safety/what-is-the-boeing-737-max-maneuvering-characteristics-augmentation-system-mcas-jt610/

[@3D2]

Boeing's real failure isn't in coding bad MCAS software. It's a failure in engineering judgment. Multiple people in the engineering chain of command did not have the sense to explore the ramifications of a single-point-of-failure design. Boeing's once-vaunted engineering/safety acumen has been lost over time, having been replaced by computer programmers and managers with insufficient awareness of, or respect for, the challenges of the man-machine interface. Boeing has a people problem, not a software problem.

[@wobblybobengland]

You mean McDonnell Douglas?

[@Wekotin]

You are correct. The Only business where one can release half finished products is a software business and fix is a patch six months later maybe. It’s scary to think that culture has spread to aviation industry. I read an article from Germany where they struggled with the new generation of engineers and lack of skill. It seems that it’s a bigger trend that new engineers don’t really have a clue what they are doing.

[@alphacenturi8038]

Spot on Daniel. We are now seeing the results of the new generation of engineers versus the old. Unfortunately the trend will get worse backed up by bosses who throw away shame to defend an obviously defective invention.

[@pizzablender]

Also seems to be a problem in tacking a safety-affecting system in that only functions rarely, is not documented, and when it goes wrong can crash the plane. That combination alone is toxic - redundant sensors or not.

[@greg1mcintosh844]

Well put and exactky right. It really is Space Odyssey 2001 Stanley

[@michaelwilson8286]

Juan, I really appreciate your updates. I'm not an aviator but an enthusiast. I work at John Wayne Airport in a support role so I'm around airplanes all the time. Your updates give me enough information that I can speak semi intelligently on the subject to co-workers and friends. I thank you for that. I am also a firm believer in the Boeing Aircraft company. They make great airplanes and this doesn't change anything for me. I'm looking forward to my first ride in a 737 MAX.

[@jimmckinnon7148]

Javiers at the airport! I hear that is a good place to eat too!

[@EVAUnit4A]

Okay, so- being neither engineer or pilot- I would like clarification on something said in this video. (Please understand I am NOT looking to start a fight, just further educate myself on this matter.) I did not/am not following this particular story through mainstream media, so I am not necessarily biased nor clingy there. So, as I understand it, these new fuel-efficient and quieter cold-air bypass engines the MAX-8 is using are far larger in diameter and weight than any other engine ever equipped to any previous iteration of the 737. To keep the larger-diameter engines from hitting the ground when landing or sucking in FOD- but not increase the landing gear height to compensate- the engines were moved further forward on the front of the wings via increased-length pylons. (Extending the length of engine pylons to accommodate larger engines is, of course, is nothing new to commercial airliner design as both Boeing and Airbus do this all the time.) At the same time the MAX-8 gets these new larger engines, the MCAS program is installed, to ensure the plane 'feels' exactly the same in the pilot's hands, to reduce the cost of retraining them for a new type of aircraft. With the new heavier engines further forward, would that not affect the flight characteristics of the MAX-8 _regardless of_ whether MCAS was in place or not? Having larger and more powerful engines, would that not affect the power of the thrust, driving the nose upwards? Isn't that what MCAS is for- to prevent pilots from accidentally initiating a stall from more powerful engine thrust?

[@blancolirio]

Yes, and that was accounted for in the design of the Max.

[@TyphoonVstrom]

What he said. By lengthening the fuselage aft of the centre of gravity, they compensated for the added engine weight ahead of the centre of gravity- with the side benfit of moving the tail surfaces further from both the CG and centre of lift, producing even more dynamic stability.

[@petersurdo4984]

I know nothing of piloting a jet. I'm a passenger. I have tremendous faith and respect for pilots and crew. I expect them to be trained correctly.

[@NesconProductions]

Would have been a good time for the Boeing CEO to show some accountability, clearly a missed opportunity. Also not the way to attract new orders, just appeasing stock holders. Thanks Juan for the continued updates and hope can turn 737 sim. time into a re-certification, best wishes.

[@freightdog611]

The 757 line should have never been shut down, IMHO. The 737 has been an amazing platform spanning many decades, but has reached the limits as to what it is capable of doing under the single type certificate. Once the current crisis has passed, I hope Boeing focuses on a clean sheet design of a new large narrowbody. Essentially, I hope the 797 is in effect a 757 NG and that the 737 is capped in its current iterations. A nice report, Juan. I'm a relatively new subscriber and have been completely enthralled by your Oroville dam spillway failure series. It's quite a fascinating retrospective documentary series when watched from the beginning. Kudos on a job well done!

[@blancolirio]

Thanks Shaun. I agree, bring back the 757. But doesn't fit 'the market' as well.

[@AR-jx6wr]

Shaun Chilson I agree. The 737 line was never designed to be as large as it is now. An upgraded 757 would have been a perfect choice. Part of the problem lies with the airlines. Flying one type of aircraft without having to retrain and certify pilots is very attractive to the airlines bottom line. The 737 Max is not a bad aircraft what is bad about it is the addition of an MCAS system that overrides the pilots judgement and not thoroughly training pilots on the new system. The MCAS system should be tamed and the pilots of all new aircraft should be trained to a more rigorous standard. Boeing and the airlines share responsibility.

[@stimproid]

When carriers stop buying a model, its probably a good time to stop building them.

[@loco4x4]

@@blancolirio The 757 line was shut down due to lack of orders at the price it needed to be sold at to make money. It was a very expensive jet to build compared to the 737 which was just, at that time, redesigned and retooled for the NG model. The NG had almost the same capability for most of the routes the 757 was flying so the NG won.

[@TyphoonVstrom]

The 757 was designed for a market that no longer really exists- medium haul intercontinental. With the enhanced range and payloads of the smaller to midsize twins that were being released at the time, the aircraft just wasn't nearly as profitable as hoped. Airlines aren't in the business of buying unprofitable aircraft. The 737 filled in the gap in the spoke and hub type transport system and the 777 was far better at intercontinental work. There was also an issue of ETOPS times I recall when the 757 was released, something which has changed now? Either way, the freight companies seem to like the 757, but they'll fly anything with wings and a big door. Some of the most successful passenger aircraft of all time have been significantly stretched during their lives- they just fill a niche perfectly. The Dehavilland/ Bombardier Dash 8/ Q400 immediately comes to mind.

[@humanonearth1]

I think you're taking a lawyer CEO position here. MCAS doesn't just maintain handling characteristics. That oversimplifies it. It does that but it also helps with stall prevention and mainly is implemented to maintain longitudinal stability. It is designed and Boeing has said to this effect, to counteract excess pitch up moments caused by the larger nacelles in scenarios of high AoA.

[@bloodguard41]

That says absolutely nothing about the plane being unstable in any way. Yes, it helps with excess pitch up. That doesn't mean the plane is prone to making those deviations to any large extent. It would rather seem that the system is designed to maintain flight characteristics equal to those of previous 737 generations and, within those parameters, may help with potential stall situations. Again. Says nothing about the plane's "instability".

[@humanonearth1]

@@bloodguard41 If you follow the aerodynamic viewpoint of aircraft design you'll understand that increased RSS leads to greater efficiency. But it requires autonomous systems and aerodynamic changes to make the aircraft stable. When you have a system like MCAS that fails and is poorly implemented, it is in effect designed to mitigate increased RSS. If it is faulty the aircraft is unstable.

[@user-yt198]

Unfortunately information at the last part of the video is incorrect: At low speeds and with a few degrees of AOA, lift created by engines move the nose up and in turn increases lift component more and nose up behavior more, and this continues until aircraft stalls. In control systems we call this effect *positive feedback* and it is the result of INSTABILITY. MCAS is required to save aircraft from stall at certain conditions. Without a fully functional MCAS, 737 MAX is not airworthy. Then its controllers and sensors have to be fault tolerant. It doesn't matter it complies with FAR part 25 or not. An unstable system is unstable. Regulations do not change that. Period.

[@cabdolla]

Hakan Evin MCAS moves in only one direction, which means it’s unidirectional. An unstable system would require bidirectional control at a substantially faster bandwidth to stabilize. Moving in one direction isn’t really moving the eigenvalues to the left.

[@user-yt198]

@@cabdolla According to Boeing, MCAS is not intended as a closed loop controller to bring AOA to a set value. Boeing just wanted to compensate unwanted lift created by engine with a counter force by moving the horizontal stabilizer. The "closed loop controller" at that stage is the flying pilot himself. That is why MCAS is only active in manual mode.

[@blancolirio]

MCAS is not a stall prevention system! Pilots are. Have you had a chance to fly the new Max yourself and test this?

[@user-yt198]

@@blancolirio If you are talking about F-35 pilots, you may be right. But in civil aviation instability is not allowed. Boeing might have persuaded you that those crashes are natural, but people who are not naive or paid by Boeing know that greedy accountants caused the disaster and now they need to pay for it.

[@user-yt198]

@@blancolirio R. John Hansman, professor of aeronautics at the MIT, says 737 MAX is UNSTABLE and can STALL: "As I understand it, at high angles of attack the Nacelles -- which are the tube shaped structures around the fans -- create aerodynamic lift. Because the engines are further forward, the lift tends to push the nose up -- causing the angle of attack to increase further. This reinforces itself and results in a pitch-up tendency which if not corrected can result in a stall. This is called an *unstable* or divergent condition. It should be noted that many high performance aircraft have this tendency but it is not acceptable in transport category aircraft where there is a requirement that the aircraft is stable and returns to a steady condition if no forces are applied to the controls." www.forbes.com/sites/petercohan/2019/04/02/mit-expert-highlights-divergent-condition-caused-by-737-max-engine-placement/#29afa6a140aa

[@7heRedBaron]

Having watched this channel, I understood what went wrong with the MCAS and why they didn’t want to call it flawed. But I thought the President of Boeing did a horrible job explaining the difference between a flawed system and the unforeseen results from the AOA sensors failure to reporters who are not educated in aircraft and familiar with them. It’s unfortunate he hasn’t spent more time watching Juan on KZbin to learn to better explain Boeing’s systems. I suggest he get some cards made to refer detailed questions to this channel.

[@jetfaker6666]

It is a flawed system. Sensor failure should never be unforeseen. I've spoken to an airbus engineer who said it's insane that boeing would drive a flight control system off one sensor with absolutely no redundancy. All systems in airbus planes have double or triple sensor redundancy.

[@zonary1]

@@uploadJ they ought to just apply the K.I.S.S. system. And disable MCAS, and rig the plain up to run old school. At least they would have stable air planes, and could recoup the cost.

[@jadesluv]

Jet Faker, wasnt it an AirBus that crashed into the ocean off the coast of SA due to a sensor failure? Air France 447, 3 pilots were not able to correct the problem and they flew it into the ocean. Same senario but with AIRBUS

[@jsprivate9332]

@@uploadJ They made the first mistake by flying through a severe storm, there 's a reason pilots are required to fly around storms air is unstable icing conditions can occur and when you compile all of that with a rookie pilot at the controls adds to an already complicated situation.

[@i.r.wayright1457]

Juan, if you get that SIM ride, spend some time at local restaurants and try to find some assembly line workers to chat with. Ask them if they are satisfied with quality control and safety. I realize the union and management have had their problems, but if any safety violations occur it is everyone's responsibility to correct them before wheels leave the ground. There are you tube videos detailing cover ups in the past and we need to know if changes and safe guards were satisfactorily addressed.

[@sledawgpilot]

Bold idea for you to suggest flying the sim. Good on ya man, don’t take no for an answer! While the MCAS May be flawed, when you said “fly a known pitch and power setting” when unsure about automation, that kinda says it all.

[@sledawgpilot]

c7042 agreed.

[@richardburguillos3118]

Great update and reporting as always. The stability of your reporting is never in question. Love that cliff hanger at the end...

[@charlesdillon7663]

The comparison I would like to see in a simulator ride would be the previous version of MCAS, along with the conditions that caused the failure, followed by in identical ride with the 'fixed' software. The two pieces of data I have not heard about the accident are if the flight data recorder showed the AOA sensors out of agreement in both accidents, and if there was a history of pilot complaints from events similar to those which caused the crashes. A lack of responding to feedback from pilots(users) would be the true symptom of a failure to care about software quality.

[@docholliday6635]

Really like your videos Sir. Your more informative than the media. Total respect for you Sir.

[@docholliday6635]

@@MrCallingoccupants your welcome! Just giving the respect the man deserves..

[@tigercat3864]

Boeing should have thrown the MCAS under the bus instead of the pilots. So MCAS makes the plane fly like before which saves everybody time and money, and the pilots don't need to know how to fly the new dynamics. And if MCAS fails the trim runaway procedure can shut it down, fine. However now the pilots are flying a plane with dynamics that they were never trained to fly. Or am I missing something here?

[@stimproid]

From what I've heard, the dynamics aren't that different. A bit lighter controls when pitching up under high throttle settings.

[@ahungryflyer]

Juan did an excellent job explaining why MCAS exists in the first place in an earlier video. The MAX series are not unstable they are just a little light on the nose in high speed high alpha scenarios compared to the NGs. Nothing unstable about the aircraft itself, it is about maintaining similarity with the 737NG type.

[@chumanho]

By training the pilots to fly the new dynamics it gives them complete control, with no crazy software misled by faulty sensors taking control away from the pilots, but installing the MCAS, just like you've said, saves everybody time and money, until something goes wrong that is.

[@joevignolor4u949]

In the Ethiopian accident the crew had large runaway trim. They had turned the MCAS off, but the design was that disabling MCAS also turned off the electric trim feature. As such the pilots were having trouble manually re-trimming the airplane. So they turned MCAS back on to reactivate the electric trim and MCAS nosedived the airplane again.

[@jadesluv]

@Vignolo, this is true, except that the aircraft was being overspeed an they should have reduced that which would have reduced external pressure on the trim, an reduced back pressure on the yoke and im guessing they didnt flip out the trim handle for extra mechanical advantage either. I will never fly on those airlines because of the poor ground maintenance and poor piloting skills, due to lack of SIM ? Both which contributed to the crashes.

[@HEDGE1011]

I think your commentary on the Max is the best on KZbin. Like you, I hold an ATP and a B-737 type rating (along with 8 others). I've flown a variety of 737s from the -200 to the NG (no Max). I hope you get your MCAS sim and look forward to the results of it. If I'm honest, though, I'm not sure what you're saying about FAR 25 is 100% correct. Here's an excerpt: 14 CFR § 25.203 - STALL CHARACTERISTICS (a) It must be possible to produce and to correct roll and yaw by unreversed use of the aileron and rudder controls, up to the time the airplane is stalled. No abnormal nose-up pitching may occur. The longitudinal control force must be positive up to and throughout the stall. In addition, it must be possible to promptly prevent stalling and to recover from a stall by normal use of the controls. While MCAS had the partial purpose of making the plane behave like a pseudo-NG, my understanding is that at certain combinations of CG, AOA, and thrust the Max did not meet the FAR 25 stability requirements without MCAS. Given Boeing's well-documented desire to get the Max shepherded through certification ASAP due to Boeing's surprise at NEO success, I cannot imagine them adding anything to the aircraft that wasn't absolutely required. I'm not trying to be argumentative, but I'm not convinced there isn't a stability requirement for MCAS to be on the aircraft although getting Boeing to comment productively on this has been challenging as you note. The Muilenburg comments you've discussed in particular did not inspire confidence. I don't have a personal horse in this race: I no longer fly the 737 and doubt I'll ever have to again, but it does seem that there is still much to uncover about the Max given the recent news about the WN aircraft design understanding versus installed reality. Please keep up the good work. Special kudos for breaking out the Boeing costs. It seems the biggest misconception now is that the Max debacle is "only" going to cost Boeing $1B, when, as you say, it's going to actually be multiples more. Good work and thank you.

[@ReluctantPost]

Where did you get that info about stability? I've heard nothing to that effect in professional circles; only suggestions of it from the media which has claimed or implied all sorts of ridiculous nonsense. Everything I have read and seen on it indicated that it wouldn't qualify for single-certificate unless the stall in that corner of the envelope handled more closely to that of previous models. Not handling the same didn't mean it was unstable but that it was different enough that an unwary pilot trying to power out of a low-speed, hand-flown situation could get a bigger nose-up moment from that action than from previous versions. The FAA is definitely averse to surprises. I suppose we could say that flat-bottom nacelles tending to start a slow porpoising in cruise meant that update was less stable than the previous generation, but I doubt it made a difference in the intent of FAR 25.

[@trailingarm63]

I guess the Boeing executive had been warned by his lawyers not to admit liability ahead of any settlements with the families of those killed. In a way that's unfortunate because it makes him look like a conniving rogue (or an idiot) depending on your interpretation. But it's clear enough to everyone that Boeing has made a hell of a mess of the MCAS issue from start to finish. It's quite a lesson for the company especially as it has wasted 346 healthy lives. Likewise the FAA has been exposed as incompetent to grant type approval where sophisticated systems are involved. In a way that's even more troubling than the MCAS debacle, because it means future mistakes are possible.

[@OOpSjm]

Everything is vetted by the "crisis advisors". Large corps have crisis management plans ;which either them or their insurance company will have a team on retainer. This team of lawyers and former execs will drop in and essentially take over. Every statement and action will be scripted and vetted beforehand.

[@GH-oi2jf]

Trailing Arm - He should not admit liability, but he reallyshouldn’t be drawing conclusions at all. That’s the job of crash investigators.

[@antonystringfellow5152]

The World will now have less trust in FAA certification, no doubt about that. This will hurt all US aircraft manufacturers and give an advantage to the likes of Airbus.

[@dugsdale]

thanks for the update, and especially for the comment about MCAS not being added to make the 737 Max "stable." That's a point I haven't seen being made anywhere else and I was not aware of the distinction myself. Appreciate your work and your explanations!

[@chrisruef9221]

Great teaser at the end. I'll be watching for your next update Juan.

[@blancolirio]

This may take awhile...

[@bryanrocker5033]

Thanks for the update and keeping us posted in a clear concise fashion. I am still not sold on the MCAS being certified initially with only 1 AOA input. I am also not convinced that Boeing is addressing the human factors and all they are doing is throwing "quick fixes" at it. If you have ever been to the Boeing 737 production line, it is quite impressive. The aircraft come in one end and are constantly moving from one end to the other. Have a great day, its a cool 60 degrees and we have more rain headed our way. Now where did I put my flippers....

[@vetere0599]

@3:56 I think Chewy is giving his angle of attack and input here. Thank You Juan for your myriad of knowledge and great vids. I HOPE they let you in the simulator what fun that will be! Safe travels! Goodnight from the East Coast.

[@fizzys26]

You’re the only source I go to for aviation updates now. Thanks for being so reliable!

[@toysareforboys1]

I sure hope you get a ride in the simulator with the new MCAS software! Good luck!

[@HeartlandTuber]

I hope they will let him film the process! So Juan can show it to us.

[@boladaletaiwosalawe4816]

@@JeffBourke 😀

[@ericbedenbaugh7085]

@@JeffBourke Airbus has a similar system called Alpha Protection which nearly caused the crash of Lufthansa 1829. It seems like an over-reaction to Air France 447. The Ethiopian pilots made a crucial error: they never disabled the auto-throttles.

[@coollasice4175]

*_Psst, bring your own parachute and stuff it under your seat._*

[@obelic71]

@@dahawk8574 its 1 system that sucks not the entire 737! +/- 4500 very expensive 737's are in backorder so its way much cheaper to fix the problem because they won't sell no planes anymore. And yes ist a perfect storm of beancounters and regulators mishaps. The reason why Boeing did it is also logical. There is a certified pilot shortage and retraining on a other model costs alot of time and money. To get an upgraded model certified faster you have it to behave like the older models. And as an airline you also opose "unescessary" retraining if you upgrade to a newer model. And there is a fleet renewal and expansion boom for more economic and high capacity/ultra large range aircraft worldwide. Boeing and the regulators tickeled the dragons tale to much. This could also could happend to an other maufacturer! An industry wide wake up call, an upgrade and/or adding extra safety equipment to a model does not mean that the model is the same. Let the lives lost, not be lost in vain!

[@youtube.youtube.01]

The conduct of a company handling a disaster resonates different ways with consumers. Here are ideals used be good leaders. 1. A company who can't own their problem also can't own their solution. 2. Professional operators of any product have the final say over every engineer or executive about a declaration of safety. 3. The value of any streamlined certification process will always be revealed after a disaster. 4. Optimizing products is an experiment and should be treated as one. 5. We no longer have an economy that isolates or confines financial disasters to a single company or region of the country. Social and economic interdependency is a reality.

[@deandanielson8074]

Juan, once again you are clear and straightforward in your explanations and provide meaningful and helpful updates on the 737Max situation. The American and world flying public need this information and set of facts. Thank you and please continue in this helpful pursuit for truth. - Dean from Minnesota

[@JeffreyBue_imtxsmoke]

Great content Juan. You have become my "go to" content creator for commercial aviations topics like this. I like your "no nonsense" approach to investigating topics like this.

[@DouglasKubler]

So the CEO said Boeing did a proper implementation of a design. Unfortunately the design did not call for redundancy or better yet, enough logic to recognize the pilot is trying to override the MCAS.

[@gordonrichardson2972]

Douglas Kubler He sounds like the proverbial kid caught with his hand in the cookie jar.

[@justcubbin]

They mistakenly installed the HAL2001 version of the mcas software instead of the MCO-MFAP* version because it was 5 dollars cheaper per aircraft. * Manual Computer Override - My F%&king Airplane.

[@theashpilez]

yes that's what I said...lol.. really

[@bruceavis1610]

Yeah if you are going to bury a system with that much power deep in the checklist so you don`t have to properly train pilots on it`s operating characteristics....... you better make it smart!

[@gordonrichardson2972]

Bruce Avis So true! Relying on the emergency AD procedure, was a crime worse than the original error.

[@HamBown]

Thank you, once again, for providing the most comprehensive and level-headed analysis of this situation that I have seen. Your valuable insight and distinct lack of lawyerly butt-covering is greatly appreciated!

[@luckyirvin]

i believe we see the weakness inside the transfer of industry executives across vital government regulation and private industry.

[@Supernumerary]

Irvin- Yes, this business to government crossover is why government pressure increases daily to inject everyone with mystery fluids brewed in filthy vats in China, by politicians arguing to mandate sales for pharmaceutical corporations which have ZERO vaccine damage liability. As for me, I want to mandate that everyone transport themselves via Segway, in the streets and expressways, by law! Envision Segway resisters driving trucks amongst Segway traffic. Everyone must go by Segway to increase herd safety. It will be the law!

[@jerry2357]

While you might be right concerning senior executives, at a more technical level, where are you going to get the regulatory experts from, if not industry? The real problem is the possibility of people returning from a regulatory role to industry (at all levels, right up to the top). If people think that they might need a job in industry in the future, then how can they stand up to any company that might be trying to pull a fast one? On the other hand, if they know that they will be backed up by management and government, and can continue in the job as long as they need to, then they will be in a strong position to stand up to the companies.

[@flybyairplane3528]

Supernumerary speaking of the vaccines, I forgot which Prez that did that, to AVOID LAWSUITS. CHEERS from NJ

[@lylestavast7652]

because government is perfect, no ?

[@michaelwatson113]

Your channel helps me get past the social and mainstream media's fixation on oversimplified and distorted reported, often blinded by outdated idealogies: reductio ad absurdum.

[@terryparkinson5473]

I know this is off subject but what about an updated report on the Amazon crash. Old C-141 wrench at Travis here. Love your work.

[@jonharrison2590]

I think he already concluded suicide

[@rohanbaty3155]

What you said about MCAS being put in so that pilots didn t need to get a new type,certificate clarified things for me. The Boeing 737 Max is a stable aircraft it just has software out in to make it handle like the other 737s . SO helpful. Thx

[@douglastong3208]

Thank you, once again, for your outstanding reporting on this story.

[@sharontorgerson2556]

Thank you for your continued work - and, btw, I really enjoyed your video on riding the back roads with your bike a few weeks back, and also seeing the super bloom in CA - I wasn't able to post for some reason or would have left a comment. I did send the link on the off road riding to my son who loves his Harley. I know the bike is a different order of things but your love of the open road, back trails, and understanding of the equipment is pretty much same as that of all bikers. I knew he would enjoy seeing what you saw and how you traveled. Thanks much.

[@General_Confusion]

I think your most poignant statement from one of your previous videos, is that when a pilot encounters this it would be terrifying. I wouldn't mind betting, that for a pilot who is fully aware of the consequences in real life, it could be quite unsettling even to experience it in the simulator.

[@cliffh8486]

Juan, Boeing would be blessed to have you in the cockpit with a camera defending them! Thanks again for simple facts on a topic that everyone else is getting so wrong.

[@mimatimas]

Great series of reports on this hugely important matter. I have a basic question which I appreciate is probably theoretical: How much different is 737 Max's operating flight envelope from the earlier models, assuming MCAS was not put onto the Max aircraft?

[@marktownsend7361]

Absolutely the best information out there on this topic, Outstanding Videos Sir.

[@pilotactor777]

watch 60 mins australia on this. The Mcas system runs trim down for 10 seconds, then goes off for only 5 seconds.And then repeats this cycle over and over.The expert pilot in the episode showed that to get out 'the "runaway trim checklist" took about 3 seconds. To then go through the checklist whilst fighting the aircraft and the various overspped 'clackers' and stall warning horns going off is not a process that any pilot could follow-it was simply expecting too much of the pilots.!!

[@HTHCLLC]

Don't let up Juan. We really want to see you fly that bird. IMHO It is the best thing Boeing could do to restore faith in there design.. Plus I am sure all of us would like to see you put your "Skills where your mouth is" < This is a loving joke. Full respect to Juan and what he is doing for us.

[@General_Confusion]

As an Engineer, although nothing to do with aircraft. It seems odd to me that a failure of this system creates a different set of conditions IE, The autopilot turning off, without indicating to the pilots why the autopilot has turned off, as in what false or unreliable input has made it change state. I would have thought that in a failure of the system, the safer option would be to give full control of the aircraft back to the pilots without automatic restart, and tell them they need to consider the possibility of a potential stall. From the nose rising due to the forward/lifted positioning of the engines and throttle position. Far more time would be available for the pilots to counter a stall that isn't if fact imminent, than there would be for them to try and find a solution to the problem whist fighting to stop the aircraft nose diving into the ground. Particularly at such low altitude. Just my uneducated opinion you understand. But i don't know of another machine that is intentionally programmed to go off and do it's own thing on it's own when it encounters a fault.

[@Milkmans_Son]

What automatically restarts?

[@General_Confusion]

@@Milkmans_Son The MCAS resumes dropping the nose after 5 seconds. Not a lot of time to assess what has happened before it happens again, and repeatedly.

[@maubur]

Are we missing something here? The MCAS was programmed to counteract the aircraft's tendency to pitch up under power due to engine placement and characteristics. If this is so, why wouldn't it be related to stability issues? It is in my book.

[@blancolirio]

All underslung jets pitch up when throttled up...

[@mateuszzimon8216]

@@blancolirio But to cover this on MAX Boeing use MCAS because pitch more than NG.... And Type Rating was point to sell MAX

[@maubur]

@@blancolirio Yes but did the NG need MCAS? Does the A320 NEO with the same Leap engine option need MCAS? Nope. A320's ground clearance allowed for conventional mounting of the engine whereas on the MAX the engine had to be moved forward and upwards, increasing dramatically the aircraft's tendency to pitch up and creating stability issues. These are very powerful powerplants. Enter MCAS. Two planes down and counting. 😟

[@thilomanten8701]

@@maubur Indeed, though as all underslug jets pitch up, the engines with the MAX litteraly cover the downwind part of the wings. Resulting in a diffused and turbulent incoming flow on the upper wing side, reducing the lift and moving the center of force further backwards, adding to a pitch up moment and adding to the risk of stalling the aircraft further down the "road". This 60's design is at one's wits end. Boeing needs a new aircraft as they have shown with the 777.

[@bloodguard41]

@@maubur You're missing the point. The NG didn't need MCAS because it already complied with the type requirements for all the other 737 planes. The MAX, because of it's slightly different, characteristics, does need the MCAS, but ONLY so that it could meet those same requirements. On it's own, the jet is just fine and could be certified without any problems. It would simply be a different type rating and that helps no one.

[@TheDutchSoupPissingCompany]

Juan, you are one of the very few sources of not- hyped and real information. And than you manage to explain it to laymen like me.You did it with the dam and are now doing it with a complex airplane matter. Thanks Juan.

[@tjernagel]

I’m still living in the same ditch. Even if MCAS was the worse design in aviation history the effects of it was Runaway Stab Trim and a qualified properly trained 737 pilot should be able to respond to it when it occurred. I read the Preliminary Report. The Flight Crew was manually trimming the aircraft with the yoke switches between the MCAS inputs (MCAS cuts out when Flight Crew trims). What I don’t understand is why did they quit trimming the stab at 2.3 degrees airplane nose down? Even at 2.3 degree AND on the stab they were still climbing and it wasn’t until they turned the stab trim back on that MCAS cycled again trimming the stab to 1.0 AND. At 458 kts when the nose dumped over that was all she wrote. At that speed they were descending at 46,381 feet per minute from approximately 13,000 ft… My question is “Why is no one talking about thrust being set at 94% and overspeed?” Had they pulled power back to 70% or less the aerodynamic forces on the horizontal would have lessened making it easier to trim it back to a manageable state. Flight 302 was so far out of the flight envelope, stab out of trim and overspeed, it made it impossible to recover. I wonder why Boeing doesn’t simply get rid of MCAS and have the pilots fly the airplane. I’m thinking it became a FAA certification requirement but don’t know that for a fact. I don’t necessarily “blame” the pilots. I put the responsibility on the air carrier to properly train their crews. The First Officer had no business being in the right seat with the few hours he had. Its an aircraft that is type certificated for two pilots, not one and a kid... AOA DISAGREE is a customer option. I just purchased a new motorcycle. It cost me an additional $5,000 to get one with an airbag. I can ride it with or without an airbag. It’s a nice to have for me. A 737 can be flown with or without an AOA DISAGREE message. AOA vanes have been on large aircraft for a really long time without an indicator. Boeing has reduced the build rate in Renton from 52 to 42 a month. By the time the 737max is back in the air, there will be approximately 150 to 200 MAXs parked. It will be a year before Boeing can get back to the normal production rate of 52 aircraft a month if not longer. The grounded aircraft still have to go through the delivery process... Dennis Muilenburg has been a great CEO for the Boeing Company. He is only simply stating there is not one cause to the accident. There is a chain of events. Sure MCAS is part of that chain and so is flight crew training and control the aircraft.

[@davesdelta7836]

Amen brother...obviously you are one of the few that really understands what really happened in that airplane. I can not fathom why they gave up on trim and never pulled the throttles back? On another note, The AOA disagree light is no longer an option, it is standard. You bring up a good point, my new 2018 Ford Platinum F-350 truck had several options that added $10k to the overall price that would be considered safety enhancements.

[@KevinJones-pj8kx]

Thank You for your continuing coverage of this. What i have not heard discussed anywhere after reading the preliminary reports ia that both crashes were chain of events as you spoke of beginning with pilot side instrumentation issues. Lion Air had been chasing a problem for months and had done maintenance before that flight. No record of a test flight before the crash flight. This seems like it should have happened due to the trouble that aircraft had been experiencing. The Ethiopia flight also had an incident in previous months of pilot side instrument issues. It had not returned until the crash flight after previous work. This flight also had serious pilot side instrument issues that appeared at rotation with airspeed and altitude low plus the absolutely impossible AOA readings. In Both cases the pilots failed to first and foremost fly the airplane when the automation began to misbehave. After hearing if the issues and the fix i think it is solved. I have heard that there are many airlines with the max aircraft that have had absolutely no trouble after reviewing thousands of hours of flight data. One wonders if the differences in what overseas operators are doing things differently enough to be at least part of the problem resulting in these crashes.

[@cptomes]

Thanks a lot for posting these videos. Your KZbin channel and Mentour Pilot channel are all anyone really needs to cut through the bs on this.

[@efox2001]

Not using both AOA inputs was a design failure. Claiming that MCAS works behind the scene and then not providing redundancy is incongruous. I love Boeing, but they screwed up and they should man up.

[@leeoldershaw956]

I'll have to differ with you about the MCAS not affecting stall characteristics. It appears the the slope of the yoke force curve became "unstable" at high AoA; i. e., that more force was "not" required for increased AoA. This is a flight regime never encountered in normal flight but is in part 25 anyway. The CEO is still trying damage control too late. I spoke with a university software professor who said the MCAS design would have been laughed out of the class in "Software 101". Saying they followed all the certification rules is damning of the system. This will be covered over by the FAA and Boeing if possible. This makes the Comet pressurization failures look trivial, that was an unforeseen failure. I have long protested the new automatic trim systems on aircraft that can get you out of trim quickly when startled low information pilots freeze on the controls. I hear that the 777 even has something similar. Be careful.

[@mafp22w]

Lee Oldershaw I agree with you that both the FAA and Boeing have to take cover. Boeing for financial survival and the FAA for political reasons. However, I do believe that Boeing will properly reassess their strategy going forward as they will have found that all of this effort to allow 737 pilots to fly the MAX 8 just isn’t worth it.

[@Shakrii]

While I don't watch any news, having talked to friends and others it is depressing how much regular news reports results in such significant misunderstanding by people not understanding how many separate systems there are and that they are not all the same. Especially, as you mentioned, the MAX flight characteristics not being unsafe to fly but the reason for the MCAS due to single certification. Really enjoyed over the years your reporting on the Spillway and accurate report based on current information on the MAX line (along with some very good WSJ articles on the subject & my own reading of the systems).

[@southpark5555]

Nobody can believe that Boeing made those rookie errors with inexcusable holes and gaps in their flight control software and inadequate level of redundancy error-checking. Fly by wire and dependence on electronics and electricity and computers etc is scary enough. And we need to totally avoid ridiculous holes in the software system like this. The rookie slip-up from people in the Boeing design team must never be allowed to happen ever again. Totally disgusting.

[@lrwado8150]

Hi Juan, I've been watching you long before you hit the magic 40,000 subscriber mark with YT, and now you're almost double that! You put out such a wide array of interesting videos, from your motorcycle ones(my fave as a adventure rider meself!), to your aviation ones, your desert trips and down to Mexico, and of course your world famous reporting on The Oroville Dam! What an interesting life you lead and we're all so glad you share it with us! Thanks a million and we'll see you at the ''Juan Browne Invitational Subscriber Motorcycle Ride'' coming soon to a trail near you! Blessings!

[@blancolirio]

Thanks LR!

[@mrgitau1985]

Hi i am from Kenya a plane enthusiast and i really appreciate your professional and detailed explanations. Thank you sir. I have subscribed

[@calbob750]

If there isn’t an award for excellence in aviation and lifestyle journalism then there should be. Juan Brown should be the first recipient of that award.

[@yoteoboth8449]

Well... sounds like "money" and smells like "fish". Thanks Juan good information again.

[@markg7963]

Yote Oboth Well, if it flies, floats, or ..... you know, it’s cheaper to rent. And the smell of fish and it’s relationship to money are always an issue😉

[@cryogeneric]

Everyone just wants to blame Boeing and exonerate the pilots and airlines, but that's not correct. Despite the MCAS issues, both crashes could have been avoided and those on the outside don't seem to understand that. In other words, Boeing isn't 100% at fault. Public opinion that Boeing should be taking all of the blame is nothing more than "opinion" and it's not based on the facts. LionAir and the pilots of the Ethiopian airline are also responsible.

[@markg7963]

Jason Vyzer yes, absolutely, and the fact of the matter is that any aircraft regardless of design can get you killed even without a malfunction. Flight never comes without risk. Not only are these pilots responsible, but the company’s that put them into this position without adequate experience, training, and talent. There is never a single link in a chain of events, and there isn’t here. Boeing, regulators, certification, bean counters, engineers, training, maintenance, malfunctioning AOA, airlines, and pilots. Everybody gets a piece any any little thing different might have produced a different outcome. I don’t say this to passengers, but I only have one real obligation to them.... I will ATTEMPT to honor your ticket to your destination, but I define all terms. The only thing that I guarantee, and I guarantee this with my own life, is that I will decelerate your body back to a survivable speed on the ground.... somewhere. Everything else is gravy. And I don’t enter this contract for free😉

[@airgliderz]

Wrong. To err is human. Your 20/20 hindsight proves this true. Boing did the best they can, they made a not on purpose mistake. The FAA is made of humans, they to did not see this as an issue and the FAR rules that also contributed to the problem. Boing is doing the right thing in fixing this unexpected issue.

[@charlesborlase2238]

@@cryogeneric people are not well informed. They hear MCAS activated and killed them. It's easy to understand. Media is not helping as they don't necessarily fully understand the dynamic either. Both of these crashes have a good long 'accident chain', and hopefully some good will come of it. And I don't just mean design changes at Boeing. I suspect the final report will have lots of line items where system improvements can be made, from maintenance, pilots, airline, FAA, Boeing, etc.

[@marksmith1610]

I like these updates. 737, oroville dam even the camp fires and dirt bikes. I find what he says eventually comes out in mainstream media as true amd he’s an airliner pilot! Good stuff Juan!

[@HenryFalkner]

So, the Indonesian and the Ethiopean 737 MAX were inherently stable. You are playing with words. If an additional feature intended to maintain flying characteristics of earlier 737 version actually fights the cockpit crew to the point where the plane is lost - that additional feature has made the whole plane unstable. To use your own statement - if the plane is forced to operate outside the safe envelope, all bets are off. The way I have read other videos, in the two lost planes it was not possible to engage the auto pilot without engaging MCAS as well. The auto pilot, as I read it, was engaged because setting the correct trim manually took more time than was available to avoid the disaster.

[@GH-oi2jf]

Henry Falkner - You haven’t been following this closely. MCASis only active when the autopilot is off.

[@bloodguard41]

"You are playing with words" No, he isn't. You are not understanding the words. The plane's characteristics, on it's own, are different from those of all the other 737 planes. That is why MCAS is there for. To make the plane feel like any other 737 type of plane. Without MCAS, the plane behaves slightly differently and would need to be certified for another type. But that in and of itself does NOT mean that the plane is unstable. It flies just fine. "The way I have read other videos, in the two lost planes it was not possible to engage the auto pilot without engaging MCAS as well." That's completely incorrect. In order for the MCAS to function at all, the autopilot must be off and the flaps must be fully retracted. Maybe you meant something different. "The auto pilot, as I read it, was engaged because setting the correct trim manually took more time than was available to avoid the disaster." Assuming you're referring to the Ethiopian crash, the autopilot was never engaged. They disengaged the stab trim motor, as they should have, and tried to trim manually. Unfortunately, they couldn't do that because their speed was too high, since they were still at TO/GA position on the throttles. Worst thing is, they had the time. At the moment they reengaged MCAS, they were at about 6000 ft AGL. Throughout their entire ordeal, they were actually CLIMBING. It's a damn shame.

[@bloodguard41]

@@StephensEFRC Wrong.

[@HenryFalkner]

Thank you!!!

[@bloodguard41]

@@HenryFalkner Well, if you're happy being wrong, I suppose it's a good thing you found a buddy to tag along with. :P

[@peterbrown6224]

Thank you for giving us so much of your time. It's appreciated.

[@pak0033]

The best information on any KZbin channel on the 737 Max MCAS.

[@t.w.3]

Excellent video again. I hope you will get access to the B738Max simulator and get some time with the "new and improved" MCAS.

[@Pietari55]

Thank you for this report. Boeing is going to get heavy a legal challenge to answer for the liability issues.

[@mellissadalby1402]

I very much appreciate getting the straight details on this issue. Unadulterated data seems increasingly rare these days, so this video feed is a welcome "anomaly".

[@JohnSmith-xb7nn]

as always, thank you juan for the fact finding videos!! 🤙🤙🤙🤙

[@duanequam7709]

Once again you have made the muddy water more clear. Thanks for your efforts.

[@mongolike513]

When the Vegas suits took over Boeing quality went out the door as Boeing workers were now being treated as just another impersonal input. The business then spread its construction over all the best tax havens in the States and the company has lost much of its in-house living history and knowledge. These executives have gambled with the lives of passengers and staff.

[@paulhull4626]

Juan! Thanks so much for your reports. I check every day for new posts. Bottom line is that MCAS was mandated by the sales department so that cost savings could be offered to the customers by not have a second type rating for the 737. The cart and horse appear to be in reverse position here. In order to sell more planes at a lower perceived cost, in comes MCAS at a now staggering sum of 6-7 Billion? Wow. Looking forward to the simulator video. If Boeing won't offer it, do private flight schools have it available? I'm sure there are many here who would GoFund You for a comprehensive run through of both new and old MCAS.

[@ecleveland1]

Juan, I think I heard you say that the pilots on the new 737 Max are trained if the AOA is giving faulty readings. Do you as a professional pilot trained in the operation of many different aircraft and the equipment thereof, think that the pilots new to the 737 Max received the necessary training to handle an emergency like the ones that caused the two crashes?

[@michaelstuart9858]

Nice job Juan. I look forward to your review of the MAX after your sim session. I’m headed to 737 NG recurrent next week, to get current (formerly only classic some 20 years ago) and begin teaching the NG. Keep the info coming...rays of light to many of us keenly interested.

[@100SteveB]

Wow, $7 Billion in cash and they were charging extra for important things like angle of attack disagree warning lights? I certainly hope they have learned the error of their ways. Thanks for the update, Juan.

[@blancolirio]

stepping over dollars...

[@keithreynolds3801]

GREED IS GOOD! Options costing over 300+ lives. Shame.

[@mpillor1]

Always Enjoy your perspective, Juan. I've never flown a Boeing or Airbus. Beeches, Cessnas, Pipers, Stinsons, Champs in lots of flavors - normally-aspirated, SE. The Luscombe behind you looks pristine. Looks like decent flying weather. Julie Ann and Pete will be old enough to polish her to perfection before you know it. As long as they can take her flying.

[@PamOrl]

Some major media network needs to hire Juan to cover aviation issues. He gives the clearest, most precise, low-fat explanations and descriptions I have ever heard on these issues. TY, Juan!

[@higgydufrane]

It was a very good day when I found your Channel. Keep up the good work!

[@freddyrosenberg9288]

The 5 million dollar question is WHY are AOA indicators failing at such a rate... that seems to be the spark that ignites the fire.

[@jonanderson5137]

Its an electro-mechanical part and built for a redundancy dependent system. Murphy is a sonofabitch.

[@GH-oi2jf]

maxbored - Perhaps they are not as reliable as they should be, but you cannot expect perfection in such a device. The system must be designed to accommodate failure.

[@alanjenkins1508]

You can see what the problem in Boeing was. There was a conflict of interest between management that wanted MCAS to be an invisible system that pilots did not need to be trained on, and engineers that probably wanted to build a better system which would have a planned failure reversion mode, but pilots would have to be trained on.

[@rustycalvera977]

wait a minute.....the 737 max.....has bigger engines which needed to be placed forward on the wing to fit.....this placement causes an additional nose up force during flight...I was under the impression MCAS was employed to compensate for this nose up force allowing pilots trained on previous 737s to fly 737 max aircraft with no further training required. This sounds to me like the 737 max required additional technology to retain the stability of its predecessor, but that overall plan envisioned by Boeing fell tragically short of success...this thing is so sad.

[@mbonje4948]

This video, to me, seems to argue that the plane is stable. This is the kind of thinking that has ended with over 300 people dead. True airplane accidents are always a chain of events, but I thought Boeing had agreed that revising MCAS would break the chain. I think we are splitting hairs here. Why then bother with MCAS if it was stable? That plane is unstable but that does not mean it cannot be flown. I have heard of military planes that are inherently unstable and can only be flown with computer assistance.

[@ReluctantPost]

@@mbonje4948 It's not splitting hairs. MCAS just improves the handling in one corner of the flight envelope so that the nose feels heavier at the controls and is similar to the way all other 737's have handled in that situation. That's it. It helps a pilot in that situation not get into unexpected trouble with more nose-up pitch, but pilots can fly the MAX to all edges of its approved flight envelope without any computer assistance. That is why it is regarded as inherently stable.

[@mbonje4948]

Thanks. I should add that I am just an enthusiastic passenger and I now notice your definition of stability (and Juan's) is quite technical and specific to your profession. To a layman like me it's tempting to conclude that if it tends to raise it's nose (unlike it's earlier iterations) then when compared to these earlier iterations, it is unstable. But this is a loose definition of stable. Blame the Internet for letting layman eavesdrop on your technical channel. So those two crashes were largely caused by poorly trained pilots?

[@ReluctantPost]

Abisai Mushaka We really need to wait for final reports and any additions or dissents expressed by the several investigation teams involved. There are definitely problematic pilot issues that are raised in the Ethiopian preliminary report just as the MCAS design/implementation and sensor malfunction issue appear to have contributed. The final reports are likely to cite a number of factors. So far as I am aware, there has been no indication that the MAX characteristics were unstable but only that they were somewhat different in that specific corner of the flight envelope when they needed to be essentially the same as other 737s to be on the same certificate. All airplanes, including airline aircraft, differ in their flight characteristics, especially towards the edges of their flight envelopes. If one is inclined to pitch up and another to pitch down, those are just characteristics that the pilots and systems respond to as needed, not instabilities, weaknesses, or threats (unless they are extreme, but then the aircraft would fail certification, not just being on the same type certificate).

[@bloodguard41]

@@ReluctantPost Agree with everything you posted here. I would just say that, based on what I've read on the topic, as far as the pilots themselves are concerned, the different characteristics are pretty much negligible. The MCAS exist simply because, on paper, the MAX, in certain conditions, behaves slightly differently then other 737s and that needs to be accounted for in regards to a single type rating. That's it. As far as practical purposes are concerned, the pilots can fly it just fine. That's why there's been no incidents(at least that I'm aware of) of pilots complaining about difficult control during landings and takeoffs, when the MCAS is off and it's just the pilot flying.

[@davetaylor9057]

Thanks for this report Juan. It strikes me that the AOA angle and AOA Disagree indicators on the pilot's display are very passive in nature. In the event of an AOA sensor mismatch these indicators should perhaps actively highlight their error status by turning red, flashing or both. This should not be difficult to program in the software.

[@gordonrichardson2972]

Dave Taylor There is a tradeoff between alerting the pilots, and overloading them with information. More modern aircraft have much better crew alerting systems. In this respect the MAX is just as ancient as the first B737. That is part of the issue with an old design, and common type rating.

[@davetaylor9057]

@@gordonrichardson2972 I'm a former pilot and aware of the hazards of information overload. However, given the serious nature of the problem I still think that a pilot's attention should be called directly to these indicators when a mismatch occurs. Having a generalized alarm and then requiring pilots to scan the displays to determine the cause wastes valuable time, especially if the indicators are not highlighted in some fashion. It will be interesting to see what the update from Boeing does in this regard.

[@damonreynolds6775]

Software designed to augment an aircraft such that it feels and flies like earlier 737s. But when operates _as designed_ can in the wrong circumstances _actively_ dive the aircraft into the ground during _manual_ flight if pilots don't stop it? And the Boeing CEO has the unmitigated temerity to call that 'safe'?

[@joemeyer6876]

I listened to ‘Dennis’ talk at the shareholder’s meeting, and Twice he used the phrase, “Flying the Software” quite unconsciously and cavalierly. This gave me shivers, head shaking, stuff! This is Management’s mindset, management that actually “flies” the jet! I’m keeping my eye peeled for movement in the import/export bank, you know that’s gonna come into play. Your tax dollars at work!

[@packer492]

Awesome great update video like usual. Good luck with getting to the simulator !!!!

[@370Scotty]

Thanks Juan,. Very detailed reporting! When will people realize that the CEO Doesn't make every design decision, and turn every bolt? He's the Captain of the Corporate Ship! If the ship has an issue, it's his jobs to protect the investors! Sad episode that will hopefully result in safe travel! Blaming the Pilot is not called for, he's the first one on the seen of the disaster.

[@Bill_N_ATX]

I hope they let you do the sim ride. It will be a great way to get real trusted information out to the public.

[@gordonrichardson2972]

William Wheeler Testing the revised MCAS in a simulator is a non event. Its like closing the stable door after the horse has bolted.

[@Bill_N_ATX]

Yeah, but you have to use the barn for the next horse. What happened in the past is in the past. They have to move forward. Not going to be easy but they’ll do it.

[@gordonrichardson2972]

William Wheeler The press conference seems to indicate the CEO is not yet ready to move forward. The lawyers and bean counters are still running the show.

[@ACPilot]

Gordon Richardson - The investigations are ongoing and no final reports available yet, so as a CEO you cannot say to much.

[@richardcrouse4644]

I hope Boeing's top dog humbles himself & listens to men like you. So far it doesn't sound like he has opened up completely. Thank you for staying on top of this important mainstream airliner situation. ~ from Texas

[@marvinkitfox3386]

So Boeing is basically saying that they followed correct and appropriate steps in designing the MCAS system. But that system killed two of their planes. In at least the second case, the pilot were aware of what was happening but still unable to survive it. And Boeing says the design process for the MCAS was done correctly? And they think this is a GOOD statement to make????????? All it tells me is that there are MANY, MULTIPLE other systems designed under the *same design rules*, that may also be suspect.

[@f14flyer11]

I just have to say Juan did a fantastic series on presenting the facts. The fact that having a cloaked software system that worked with hardware to make the jet FEEL like other 737's because the engines are different and mounted different thus giving different handling characteristics with changes in power settings. In addition the max 10 series is going to have a longer fuselage which again is the reason they developed the MCAS system. Now is it unstable without MCAS ? no, but it all boils down to crew training costs to have it be a common type and the only way to do that is with the cloaked system. I really wrote more than I was going to but the final fact is they are putting 10 pounds of crap into a 5 pound bag. Combine that with a possible lack in appropriate training, bad things generally happen.