737 Max UPDATE 20 March 2019

[@blancolirio]

UPDATE to the Update from AvWeekly aviationweek.com/commercial-aviation/faa-reviews-enhanced-max-flight-test-data?CPEN1000000907970&elq2=7b24c0887f88426098a9f69399830ffc%20FAA%20Reviews%20Enhanced%20MAX%20Flight-Test%20Data

[@francodafo3475]

I need subtitles, please

[@cabdolla]

On the 737-800 you flew, what was the procedure for powered on stalls. The reason why I ask is that I am trying to deduce true effects of the bigger engines and MCAS vs the hype. Can you simply pitch down to recover, or is the pitch induced thrust so great that you need the assistance of the stabilizer trim to recover? Mentour pilot hinted at this behavior in his video when he was in the 737/NG simulator (A good video to check out if you haven not. He flies out of Europe). [1] If the trim is needed, that's a scary thought, because if you have to cut out the pitch trim breaker for whatever reason, it means the airplane is pitch *divergent* during a powered on stall. There is no way to get out of it without reducing power first. I can't imagine any plane would pass certification with such nasty behavior. But if this is indeed true for the /800-NG, then I could absolutely see why the 737-MAX would have MCAS moving the trim so that when the pilot pushes the nose down to recover, the stab trim is already where it needs to be. There is no lag/delay while the jack screw is winding up and the plane is fully stalled. It will save a few vital seconds of spool time.

[@dougdobbs]

Can only see part of the first paragraph without subscribing. :( But thanks for the updated update. :)

[@ediartiva]

@@cabdolla " There is no way to get out of it without reducing power first." I watched that video, IIRC that is exactly what Mentour Pilot said. Is that correct?

[@cabdolla]

I rewatched his video, and if you look carefully, he actually did a powered OFF stall, and he easssssed the power back in. That's very different from a powered ON stall where the engines would be producing maximum thrust and pitching the nose up. I kept carefully listening to his words over and over again, and I was not convinced he said the NG behaves that way, but instead that he was thinking the max might. It was not explicitly clear, but Juan would be able to know for sure. Also, Juan, you said in this video the MCAS would put the power full throttle when the MCAS turns on, that would not be true. As far as I know, the MCAS does not interplay with the throttle, and if it did, going full throttle would worsen the stall because of the pitch up tendency at full power. It would make more sense to cut the power to half and once the AoA is below the critical value ramp the throttle back in slowly to avoid a secondary stall. @@ediartiva

[@networkbike543]

"Turns out I can talk and fly so they made me an instructor" Good line.

[@torpedo1ism]

networkbike543 : I found the humor on that too. Excelent report.

[@charlie99210]

Such is the USAF. Yes, it is true!

[@dougkathydavies3024]

Juan, this has to be the most fact-filled and technical explanation of what happened to these two aircraft and you were able to put it out there in language everyone is able to understand. Even the NTSB couldn't do a better job. You are a truly gifted journalist. I eagerly await all of your reports. Keep up the excellent work.

[@yapiciyapici5874]

NTSB and FAA don't want the public to form an opinion about these type of issues. The stock market news are the same.. Everything is vague..

[@TILEBOSS]

Again The best pilot reporter ever ! Thanks Juan

[@heybooitsme6016]

Juan is also a member of ALPA, one of the best trade unions ever.

[@jcr723]

I'm a non-pilot and have been following this closely from many sources. This video was just outstanding!

[@DingXiaoke]

jcr723 same

[@GammelKong]

40 years in the aviation business as a research and development aerodynamics engineer, airline operations engineer, and engineering test pilot on every category of aircraft from small bug-smashers to jumbo jets. While all of us can go on for hours discussing system design, operational details, and lack of pilot awareness and training, the fundamental underlying cause of these accidents was schedule and budget driven by short-term business goals and stock prices at the expense of comprehensive system design and testing, coupled with limited resources within the FAA. To avoid these kinds of accidents in the future, the FAA needs more resources and the manufacturer's ability to self-certify needs some serious critical analysis and oversight. Very nice video, sir. Well done!

[@catherinenelson4162]

G.K., I agree with you. Should Boeing have been left to self-certify? Not a chance! Boeing had an accident (I believe in the 1990s or maybe a little later, due to a rudder issue. The pilot correctly identified it, and handled it the way he'd been trained to do so - with catastrophic events. The plane clipped houses on Long Island before going into the water. Everyone on board died, as did some of the folks in the affected houses. (I'm going from memory here, so if I'm not totally accurate, I don't need to here about it). The point is, that Boeing knew about the problem and sent out a memo to be distributed to pilots. Simulator training all of the pilots on this would surely have been cheaper than the lawsuits. Fast forward 20 or so years, and here we are again, with another problem that Boeing could have paid the airlines the cost of simulator training, and once again Boeing chooses not to give that clear hands on practice. The pilots were being issued a one hour course on a tablet. Either not all had taken it, or not all had yet been given time to take it. Once again, with catastrophic results. I hope the FAA has learned it's lesson once and for all. People have blind spots. Organizations do too. A lot of people died needlessly because of this.

[@AMStationEngineer]

FYI, Juan, you've managed to gain the respect of five former (all long-retired) avionics support engineers, and industrial engineers, myself included, all who've supported the production of avionics systems for at least ten years. Thank you for providing a well balanced, honest view of the situation. The news organizations would do well to adopt your methodology.

[@livingabovethe12th]

HUGELY agree.

[@SuperAWaC]

why would they adopt that which they abandoned in the pursuit of profit?

[@MendTheWorld]

I just replied to another comment by someone dumping on the news media. Maybe I just don't go to the kinds of information sites that provide fake news. (I subscribe to the New York Times). If you wouldn't mind, could you please provide a few examples of unbalanced, dishonest reporting? (I mean from a reputable news source.) It should be easy to find, if what you say is true. Thanks. :-) I realize there are problems with misinformation on the internet, but I'm finding that the wrong people are being blamed for this.

[@hectordeleon9249]

I must say as an avionics dude my self in impressed too. Its not allnthe time you see a pilot who is also an A&P

[@lockedin60]

Unfortunately there is a certain amount of fear in trying to understand complex things so when the news media does not understand they have a tendency to act surprised and fearful. Fear drives a lot of misinformation!

[@TeachAManToAngle]

You put in 10x the effort of mass media to get the story straight. Thank you for the time and great videos.

[@maxon1672]

I found his channel a couple weeks ago after sifting through all of the garbage 1-2 minute long videos from big news media outlets. They care about nothing but sensationalism. Thanks Juan!

[@livingabovethe12th]

feel the same way

[@MendTheWorld]

Not so. Based on my own experience, this is a false accusation. I have the NY Times delivered to my house daily, and have read essentially ALL OF the information provided in this video, in some cases weeks BEFORE the Ethiopian Airlines crash. In particular on Feb. 3, when the Times ran an expose on how and why Boeing had rushed the 737 Max into production while selling airlines on the fact that their flight crews wouldn't have to undergo extensive re-training to fly the Max (which was a major selling point to potential clients). check it out: www.nytimes.com/2019/02/03/world/asia/lion-air-plane-crash-pilots.html I'm weary of people dumping on the "mass media" as if they are all the same. I subscribe to the NY Times, because I want to know what is happening in the world, and have the highest regard for their journalistic standards. The Times and other news services have been labeled the Enemy of the People. I find such accusations dangerous. (My comments are restricted to responsible journals, with strict editorial standards, such as the Times, WaPo, and the major broadcast news network, but EXCLUDES networks who have the word "NEWS" in their name, but then say they are only "entertainment", not news. That said, I appreciate the efforts put in by First Officer Juan Brown to provide this information on his KZbin Channel. The information has been carefully researched and presented, and verifies what I've read previously in the NYT.

[@TeachAManToAngle]

MendTheWorld - Great point, and I should have clarified that I was referring to mass television media that quite frequently does not take the time to get the details right. There is absolutely still some great newspaper reporting on topics such as this. But I reread your comments and noticed your strong political biases which should have nothing to do with getting aviation stories correct.

[@sietuuba]

@@TeachAManToAngle But MendTheWorld is correct and an entertainment outlet passing itself off as "news" has no value in providing information to any audience. Meanwhile, any respectable outlet's editorial board can likewise be tainted by ulterior motives just the same. Neither of these issues have any relation to the work done by the *actual journalists,* if any still remain, in the publications in question! Only journalism is, sadly, the one squeezed by financial difficulties while punditry pays leading to uncomfortable arrangements and juxtaposition. Painting journalists, and partisan political hacks and operatives with the same brush just because they have to share the same space in a publication or outlet is intellectually dishonest.

[@invertedreality4473]

I wish your analysis was more widely publicized. I realize mainstream media thinks us regular folks are stupid, but we're not. Again, many thanks for educating us in such detail.

[@mafp22w]

I always share his reports with my Facebook friends. I consider his reports real news, whereas the mainstream media is nothing but propaganda.

[@invertedreality4473]

@@mafp22w absolutely, he's a real journalist, unlike the mainstream media stenographers, or as you correctly point out, propagandists

[@glasser2819]

the media get payed to reassure flyers that American Boeing is the best in the world and blame casualties as acts of God, not Mickey-mouse enginering

[@theRatchet833]

Its the mainstream media that is stupid

[@nicholastenaza991]

@@theRatchet833 I think the problem with mainstream media to be sensationalism and ignorance, not particularly in that order.

[@billsutton9449]

As a retired airline pilot and mechanic, I have to say this is the best and most complete explanation of the potential root of these accidents I've heard yet. This sounds like a simulator training session from hell. With pilots having multiple symptoms that they don't realize are related. Much of our simulator training serves to train our muscle memory to react instinctively to the most likely sudden events such as engine failures. When presented with a novel malfunction, we have to rely on our knowledge of systems to even know where to start looking in the manuals. Unless the aircraft annuncitates the nature of the problem, valuable time is lost trying to identify it. I spent most of my career in DC-9s, which didn't have the pitch up tendency when adding power. I learned about it on the 767.

[@gordonrichardson2972]

Bill Sutton Thanks for the valuable feedback.

[@blancolirio]

Yes! Thanks Bill!

[@sirroger1]

I'm genuinely impressed with your resume. I'm in a medical field and was under the impression that pilot hierarchy progression is fairly straight forward, however it is now obvious that i was wrong. Having to undergo training on such a variety of aircraft over the duration of your career is truly impressive.

[@barryhansen6854]

I started watching you on the Oroville disaster since then have followed you these air crashes that you explain do a lot for the people like me who are just normal people that are not in this feild , thank you for what you do will always read your comments very informitive.

[@robnnorthaustin]

I'm not a pro but I appreciate all the details and time you put in these videos. We are lucky to have an expert share your expertise.

[@markhathaway9456]

The idea of a 3rd pilot in the jump seat having a "big picture" view of things is much like a coach watching his team play. They're dealing with specific things happening and their own involvement, but the coach tries to see the trends and thinks of adjustments to make. It's a pretty good analogy.

[@Mpower-hz4gk]

Makes me wonder if he spotted the trim wheels winding away whilst the pilot & FO were focusing on instruments or checklists

[@WilliamJones-Halibut-vq1fs]

I made the point that the traditional flight engineer would have likely picked this up. Not only was he a 3rd set of eyes his background and job made sure he took a different approach to assessing problems that focuses on the system rather than flying the aircraft. One thing is for sure, a flight engineer would have been very acquainted with MCAS by nature of his job. Furthermore earlier MCAS disturbances would have been of enormous interest to collegiate flight engineers. They really would have given Boeing hell on this.

[@AndrewScott83815]

The umpire description of sitting in the cockpit is more accurate than I’d like to admit. Commuting for work at the airlines has taught me how important it is to take a step back and reevaluate my SA. I can’t even count how many things I’ve seen missed while sitting jumpseat, and it made me think of how much I’ve surely missed. And as far as startle factor goes, I couldn’t agree more. Being 2000 afe and having a trim run away is scary enough, let alone the wicked nature of what an mcas failure appears to be. I’d like to think that I wouldn’t be lawn darting in that situation but I think given the situation the odds are definitely stacked against the crew. Rip. Thank you for your updates, it’s increasingly rare to find a channel with such thoughtful coverage. You have earned my subscription!

[@mikewhite4628]

At 11.25 sitting between the pilots on the centre jump seat -that's what we flight engineers did. It's a great overall picture. Bring back the third set of eyes!!!

[@ke6gwf]

As someone who designs and troubleshoots industrial automation control systems, I see 3 problems here, 1 of which doesn't seem to be directly mentioned very much, which is unreliable AOA sensors. None of these incidents would have happened if the AOA sensors were not faulty, so they need to find out why they are failing, and correct that issue, because this is an unacceptable rate of failure indicating a poor design or testing process. Second issue is lack of user training after a material change in the function of the system, because the scope of the change was underestimated. The third, and most important, and most egregious error is in making the control logic not fault tolerant. I run into this a lot when I am called in to correct a system that is misbehaving, and usually I find that the original programmer did not plan for faults, and assumed that all inputs and outputs would be reliable and within a certain framework. Basically, you have to remember that a logic control system is Infinitely creative. In other words, if you tell it to perform a certain function, you have to think of all the possible ways it could be triggered to perform that function, and program out all the ones that you don't want to have happen, and try to predict all the possible failure modes, and have a plan for them, because if you don't, the system is going to respond, because that's what logic systems do, they respond according to the inputs, with no regret. And if you simply do a textbook "if Switch A is activated by Part B, then perform Action C", how are you verifying that it is Part B that is being sensed, or that the machine is in a safe condition to perform Action C? For instance, one machine had a large frame that moved back and forth on a track, and it had a limit switch at each end. It was programed that if it sat on the extended limit switch for longer then 5 seconds, it would power it up to retract it to the safe home limit switch. This was done as some sort of fault recovery routine, with the designer probably thinking that he was really smart coming up with this to make sure that it would default to the home position. The problem was, he didn't look at anything else before acting.. The routine was simply that if the extended limit switch was tripped, the unit would retract. It didn't look at whether the machine cycle was active, or whether the Home limit switch was already tripped, or anything else. So every couple of days, the unit would randomly retract past the Home limit switch, and would over travel and get wedged in before things would trip. And then it took some disassembly to get it back where it should be. I set a camera up recording the input status on the controller, and the next time it happened I saw that while the system was idle with the home limit switch tripped, the Extended switch input would come on and crash the unit. After I found the routine mentioned above, I started testing switches and checking wires, but the switch was brand new, and I couldn't locate the intermittent short that I suspect was in the wiring, so I added a command that it would only run the routine if the unit wasn't already Home. (they were going to dig deeper and find the short in the wire, but the system never had that problem again because I had made it more aware of the rest of the inputs.) Another system I had fun on was an automatic truck wash (like a car wash, but for semi trucks, and more complicated!) It had been programed to assume that if a photo cell was blocked, that meant that a truck was that far through the wash, and would activate whatever components it controlled. This is great as long as everything is clean, but when soap scum or hard water deposits start building up on the sensors, residual spray from the 50 horsepower oscillating pressure wash nozzles is enough to trip a partially occluded sensor, activating stuff after the truck was gone, and sometimes it was the sensor that activated the spray, leading to a constant cycle. Fault tolerance was created by including the previous sensor in the logic, so that if the previous sensor had not been tripped, it would not activate, ensuring that things happened in the right order, and it would take multiple consecutive faults to cause unwanted behavior. In this case, it sounds like there was no thought to what would happen if the single sensor failed, so no checks of other plane systems, no checks of what the pilot input was, no comparison of redundant sensors, just a simple single line of code, "If AOA exceeds Angle A, then activate Stab Trim until Angle is less than A". Simple and stupid, and works great, as long as all of the inputs and outputs are trustworthy.... It almost sounds like it was a rushed afterthought, and it either was programmed by someone that didn't understand Fault Tolerance, or it was the first rough draft of the program, but the guy was put on something else, and no one completed it or it was rushed to production. They may have also justified it as not needing all that extra complexity, because if there was a fault, the pilot would know to shut off the Stab Trim because that was already a memory item, so it didn't need to be fault tolerant. If I were in charge of redoing it, based on the information I have, I would set it up kind of like how a lot of autopilots are, to fail neutral. So it would look at both AOA, and the pilot's input, and the Stabilizer position, and would take action based on which ones agreed the closest, and was the least severe control input. And then at the same time, would alert the pilots that there was a sensor failure and that they needed to take charge. For instance, if the right AOA was within normal readings, and the pilot's inputs matched the right AOA, and the stabilizer position matched both of them, but the left AOA said the world was ending and we are all going to die, then it would pat Marvin the Depressed Sensor on the head and give it a Valium, and fly according to the right sensor. Of course, a big part of fault tolerance for something like this, is training the pilots in how to respond to faults, how to recognize them, and give them the information they need to spot them. For instance, have an indicator so that they know that the plane thinks they are stalling, instead of just taking action without informing the pilots. I would be really interested to hear the story of how this ended up like this, who dropped the ball and what the reasoning was, but I suspect that will not be made public, unless it comes out in the lawsuits. But bottom line as a control system designer, this system was not properly designed and integrated into the system and flight crew, and that is the ultimate cause of these crashes, even with the aspect of the poor maintenance culture before the first one, and possibly bad training for the second one, because the technical side could have been so much better and taken those into account.

[@TSRGarage]

" Pat Marvin the depressed sensor on the head and give him a Valium" Lmao. That was a long read but well worth it. Yes Redundancy. I don't understand how they could use only one angle of attack sensor to run this system. Anyway... next time I'm troubleshooting any sensor related problem I'm going to use that quote.

[@phillyphil1513]

re: "a control system designer, this system was not properly designed and integrated into the system and flight crew" bingo. it was clearly MCAS rev 1.0, it was not tested, not vetted, and the code was likely not even written by anybody who was a pilot. having fitted 2 AOA sensors, and then both data streams not being fed into the control logic is an obvious RED FLAG. and really there should be a 3rd sensor used of different type (think gyro) fed in as a check/tie breaker in the event of a DISAGREE between the 2 AOA vanes. that or if in the event of a disagree between just the 2, then the system throws a warning, disconnects, and the pilot then has to "hand fly" the plane, which he should be doing anyway during takeoff.

[@painmagnet1]

I was thinking the exact same thing when listening to Juan explain the MCAS. THEY MAKE IT DO THAT?!? Absolutely insane. Automating flight controls to the extent that a pilot can't overpower them WITH NO REDUNDANCY, self- checks or announcement begs for the crashes we have seen. Boeing really, really pulled a boner on this one. Glad I don't own company stock.

[@AndrewTGreen]

And the AOA "Disagree" light should NOT be an option, as it is now.

[@Kimberlyk12]

That was the most interesting thing I have probably ever read in a KZbin comment haha. The video made clear how and why the system responds, why it was made, and how the pilots would handle it or react, but your comment was really fun to read, in what goes into making and designing a system like that. I do not have an engineering brain or even a clue about planes, but I completely understood what you were saying and I was made much more intelligent by your experience and insights.🤯

[@mtech1961]

You and Mentour are the best Pilots in the world when it comes to explaining things with no BS and undestandable to both Novices and laymen alike

[@kennethpack1963]

I fly a Dodge pickup, but your explanation gives even a ground pounder a good idea of what happened,thank you...

[@charlielehardy9308]

I found your channel back when you first started describing the Oroville Dam problem. Just wanted to say how much I have appreciated your very clear reports and your commitment to getting things right. These latest explanations of the 737 Max crashes and MCAS are excellent. Thank you for all you do to get good information out there for all of us. And, as a flying enthusiast, I love the way you've used the Mighty Luscombe in your channel. Keep it up!

[@JHarv901]

I too subscribed to this channel just on the Orville Dam coverage, little did I know Juan was a commercial airline pilot which my dad was too and I fly as well so this channel is exponentially multifaceted. Love it, enjoy it and even under stand it, Juan you rock man and you're the best!

[@AndrewTGreen]

Hey!!! Thanks for the unexpected rundown of your resume! I was actually curious as you had mentioned Air Force, but I had never heard you elaborate. Best Wishes and Best Regards!

[@allaboutboats]

Clearly explained so even a non pilot can understand the basic problem. Thanks very much for this spot on video.

[@MIKEKELLEY12000]

The jump seat pilot who prevented a crash reminds me of the late, great Denny Fitch in the Sioux City Iowa disaster. His presence was widely credited with the DC-10 landing well enough to save many lives. It is unfathomable that one Lion Air crew could save their jet from disaster yet not pass the information on to the next crew and indeed the rest of the fleet. If true, this is a cardinal sin. Of course Boeing deserves a ton of criticism for their bungling, too.

[@kirilmihaylov1934]

Boeing is to blame

[@glasser2819]

Boeing/Airbus automatically receive feedback of many vital signs of modern planes directly live through satellites. Letting that fresh new plane go back out after the 1st near crash was... not too professional.

[@sithus1966]

A news report I read said it was reported and a tech checked the sensors and cleared them. No report if the new crew was told of the issue.

[@bwinmaine]

@@sithus1966 Actually there's a really good source of authoritative information that loosely details this entire Lion Air crash and gives critical information even about the flight of that same 737 into Jakarta six hours earlier where the newly revealed hero saved the (day?) night actually. The saved flight landed just minutes before midnight. I can't seem to open the link today but I spent time on that website yesterday so I'm thinking it might go back online soon. reports.aviation-safety.net/2018/20181029-0_B38M_PK-LQP_PRELIMINARY.pdf

[@speedlever]

Sithus1966 it’s been a number of years since I flew in 135/121 operations, but I seem to recall a part of the preflight process is the captain has to review the maintenance logs to make sure all discrepancies are appropriately dealt with... either via maintenance to correct the issue or deferred via the MMEL as appropriate. The landing crew probably thought their issue was a one-off anomaly and wrote it up and let overnight maintenance deal with it.

[@pkettler]

Excellent video, Juan. I am an experienced commercial/instrument pilot keeping up with industry developments. In your well paced, informative video I learned at least four new concepts relating to this MAX 8/9 situation, a rare grasping of knowledge for me from an Internet video. Congratulations for your fine service to the industry and flying public.

[@triciachancey3736]

Thank you for taking precious time to explain these unnerving accidents. For those of us, just civilians who have to fly time to time, you bring us some understanding ,peace and more confidence in our pilots.

[@blancolirio]

Thanks Tricia!

[@victor-emmanuel7485]

What a resume! You can not believe how much I look up to you Juan! I myself: 26 years old, belgian, architect and lifelong aviation geek. Only a year ago I finally made the decision to start flying gliders, let’s see where this takes me. You have a fantastic channel and you are an amazing reporter. Thanks for sharing your knowledge!

[@daveingram2795]

I found you during the Oroville spillway crisis and have followed you ever since. Your excellent unbiased reporting, knowledge of the issue, and clear explanations are a rare combination that you have. I thoroughly enjoy your reports

[@billdennis2993]

Great video and technical briefing Juan. Thx for your military service and your outstanding results of keeping all of us acqurately informed. Safe Travels to you and yours.

[@bobteachesphoto6379]

Juan, I have been looking all over for a comprehensive intelligent overview of MCAS system including engine history and finally you did it! Thanks so much, an outstanding job!

[@robdavis1176]

My son and I was watching your previous episode. I mentioned to him, If I ever needed a pilot I hope it's that guy. I knew you seemed so experienced and knew you had the right stuff. After the explanation today with your background. It solidified my opinion. Juan love the episodes and appreciate all your hard work.

[@blancolirio]

Thanks Robert!

[@thomascrouch6135]

Juan, You have done a fantastic job of explaining the problem, its cause, and the solutions to these disasters. I can not complement you enough for all of the reporting that you have done. For me and a lot of others you do the best , most complete honest reporting that I have ever had access to. You are a Wonderful Man!

[@blancolirio]

Thanks Thomas!

[@ammobake]

The C-130 is an amazing aircraft. In 1998 I was stationed in Oman as part of a detachment flying C-130 supply missions across the theater for Operation Southern Watch. At one point we landed in Doha to unload a generator. When we got the go-ahead to return to Oman the metal gear on the starter for engine #2 snapped off. After waiting around for a few hours we eventually got approval from Headquarters to do a windmill start. I was a young ammo troop at the time and didn't know much about the C-130 so it was pretty scary. But it started right up about halfway down the runway without any issues. That's versatility!

[@kentbullard6917]

First time I've heard of "push starting" a C-130.

[@alc818]

@@kentbullard6917 High speed taxi - see kzbin.info/www/bejne/nJPIoJR8mdSZpK8

[@5695q]

Hurry up skippy, dump the clutch we gotta get out of here.

[@kentbullard6917]

5695q Chirp chirp----zoom.

[@kentbullard6917]

Al C Hard to really see it happen but interesting. Thanks for sharing.

[@johnr8439]

Juan, being a former resident of Paradise with lots of family that still live there I originally started watching your channel because of your reporting on the Oroville Dam. Then you're excellent reporting on the Paradise camp fire, in your true Juan style it was absolutely excellent I may add. As a civilian with absolutely no pilot experience I wish to commend you for your professionalism, extensive experience as a pilot and your detailed approach to everything you do especially being a pilot. Before I retired I did spend a great amount of time for business as a passenger in my career. Always knew that the pilots were true Pros. You have to be in the top of your field. Thank you for providing us your extensive background as a pilot. Getting to know you on your channel the last year-and-a-half has truly been uplifting in everything that you report on. With so much fake news and bias in our news media you bring the true facts to an issue. Thank you Juan it is greatly appreciated.

[@blancolirio]

Thanks John! Q-Are you moving back to Paradise? (or relocate before the fire?)

[@johnr8439]

@@blancolirio Moved before the fire. Son, daughter-in-law, grandson and in-laws still there. They were one of the few lucky ones, their homes made it. Most of the homes on my son's street are now gone. All other friends and family members lost their homes. Again thanks for your reporting on everything you made a big difference with us being out of state.

[@deandanielson8074]

Juan, an absolutely clear update on what is progressing on the 737 Max situation. As a former military pilot and instrument instructor, I can state your clarity on the issues is outstanding. Thank you.

[@jnugent262]

I am a retired biomedical/electrical engineer and I can say I've been there and done what I think you are describing-- fix a hardware issue with software. It can be done but you're on thin ice. As to why use one AOA sensor when two were available, words fail.

[@BenjaminEsposti]

It pretty much depends on what sort of problem it is. A noisy switch can be de-bounced in the system software, but a noisy system power supply cannot be filtered by software!!! The lack of redundancy is strange, I guess they must have assumed that the one sensor was reliable enough ... but obviously NOT!...

[@Animalwon]

Relying on just one sensor - Isn't that what is at the heart of the 737Max problems?

[@Alanjohnlew]

As a non pilot aviation enthusiast I have to say this is a brilliant explaination of the MCAS system and how it would appear to have caused the two 737 MAX crashes. I had picked up a lot of the information from several other places but this makes it clear and understandable to the layman. Thanks.

[@petecollins4925]

One of your best Juan, thank you. So good to get these factual reports from someone with the amount of flying experience you have. First thing I learned about when I got involved in avionics was something called dual redundancy. I was thus quite surprised to hear you confirm that Boeing took the input from only one AOA sensor. Interesting points you raised about the 3rd/4th pilots wider view too, that's something us non flyers would not have considered. Good to see the subscriber count zooming upwards - keep those wackadoodle trolls out, you're doing a grand job.

[@jandypimpson]

I've been a subscriber since the Oroville disaster and since then you have offered a front row seat to the spillway reconstruction, then Paradise fires last year, and now these airline disasters. Truly amazing commentary. I must say that this overview is providing an even more damning account of Boeing's pure neglect in the development of this aircraft than is being reported elsewhere, and the reports elsewhere are already pretty damning. They are in a LOT of trouble with these catastrophes, and the US government and FAA oversight comes out looking awful as well. Yikes.

[@rlpennington5146]

Juan my background is Air Force flight engineer 22 years. 121ground instructor on the 737-200-300-900-max. 29 years. Everyone is talking about MCAS and then describing it to 800 SMYD system. My Manuel’s don’t even have a description of the MCAS system in it. I don’t know how the system actually works, I haven’t seen a schematic nothing on the max system. I can only compare to the SMYD system that is described in the 800 manual. How do I train pilots when I don’t have the the description of the max MCAS system. Thanks for your videos on the subject. As flight engineer that was my job to be the 3rd set of eyes in the cockpit and run the systems maybe we need that redundancy of the human kind.

[@daviduschock1464]

Jesus. Non-aircraft controls engineer here. At the very least, a unique audio sound that you hear when MCAS is operating. (Adjustments being made). Whoop whoop or something like that. Oh, I know what that is. Or, stern voice MCAS MCAS MCAS. You know, like terrain. That schematic and flow chart could also be flashed up on the glass cockpit. Not static, but graphically active. Minus minus flashing, or plus plus flashing overlaid on the MCAS section. These are all pilot alert improvements. Fundamentally, you should need both sensors to agree. If the two sensors do not agree, MCAS dumps out, like autopilot dumps out when given conflicting sensor data. I also like dead simple disaster check cross sensors: If your angle of attack is truly that far out, hell, a bubble sensor will agree. It won’t tell you how many degrees to sub minute accuracy, but hey, yeah your pitch is “truly” that far out. Higher tech cross check sensors could be of the inertial type. (Popular for military applications before GPS.) Millimeter radar is extremely accurate. What is the altitude of the tail? What is the altitude of the nose? Again, you are not adjusting based on those sensors; you are disaster checking. Are we really that far out of our angle of attack envelope?

[@davidsuzukiispolpot]

@@daviduschock1464 The bubble will work to inertial or gravitational pitch (I don't know what terminology to use, but I think you will get the idea), but not relative to air. Also, the spinning of the trim wheels right beside the pilot should be very obvious I think. They are large and noisy and have a high-contrast strip on them. Whatever the cause, it should have been obvious that the trim was being grossly adjusted. If I am wrong, please correct me here (pilots?)

[@simian_essence]

I like the how question. But I have a why question. Why was Boeing so non-communicative with pilots regarding the MCAS system through the training manual(s), and perhaps other channels, from or before the very first deliveries of this new 787 model??? Care to speculate? It seems criminally negligent to me for Boeing not to have communicated to pilots what this system was all about. It blows my mind.

[@--_DJ_--]

@@simian_essence I may be wrong but I believe the MCAS is designed to reduce pilot workload, not something that they should have needed to worry about coming on or off, just a system helping keep the nose down on throttle so you don't have to do it manually. If designed to work in the background I can see them not stressing training on that system, I imagine there are many things going on in a modern airplane that the pilots are unaware of the ins and outs of how it works.

[@--_DJ_--]

Not sure if you could answer this but would the pilot have a visual indication of the readings the AOA sensor feeding MCAS or is that fed directly to the system with no instrument to compare against the other AOA sensor(s)?

[@veryshadey]

Having watched your videos on the MCAS. My first thought after I saw the news of the last crash was “that must have been a MCAS problem why didn’t they just turn off the trim stabilizers.” I am not a pilot. I learned that from you. You have by far the best technical explanations for complex problems that I have seen on you tube.

[@dekepgreen]

As a former C-141 and Air Force 737 pilot, I have to say....you nailed it.

[@blancolirio]

Thanks Deke!

[@Sara_PY]

Outstanding, Juan. I appreciated hearing a bit of your history, as well. Thank you!

[@richardcrouse4644]

We have a friend whose son joined the USAF following in his father's footsteps, had much the same career as you although he is still in the AF & flying C130's. Always enjoy your videos. Thanks for making a foreign subject seem simple & logical. ~ from Cut and Shoot, Texas, Richard.

[@Sailor376also]

I have a full certification on a canoe, but,, I am very well read and have remained interested for a lifetime. Your description of cause and result I find faultless. I found and viewed this video because I already respected your skills and ability to explain. Thank you. And you did touch upon it,, the MCAS is more than just an assist and warning system. It is capable of over ruling a pilot if faulty data is entered, without redundancy. This touches upon exactly what I have been seeing/surmising. If I understand correctly, you will know, the original to the MCAS, the pilot could disconnect the system by pulling the yoke to full back,, a highly intuitive move that would simplify recovery and gain precious time. Time to then pull out the loose leaf book and run a check list while the plane is out of danger and flying under normal manual or autopilot. The MCAS is the first system I am aware of,, you likely know of more,, that can actively over ride a pilot and control the plane into something undesirable, dirt. The intuitive response of yank the yoke all the way back, was, and should be the the first line of disabling the system. Not just mute the system, or enter the redundancy of both AOA vanes, but cut out the stabilizer computer control,,, AT a minimum,, long enough to find and run a check list. MCAS is not a stick shaker, not an announced warning of "Too slow.",, or "Pull up.", it is not assistance or advisory. It is not a safety system. It IS a pilot cut out system. It stands between a pilot and his or her control of an aircraft. And that is fundamentally wrong. Even reprogrammed,, pilots should refuse to fly it.

[@gordonrichardson2972]

Sailor376also Very good analysis! There is a news article saying almost exactly the same thing: A news article suggests that an important change to the control column stabiliser trim cutoff switch may have made recovery from a faulty MCAS activation more difficult: www.reuters.com/article/us-ethiopia-airplane-controls-explainer/change-to-737-max-controls-may-have-imperiled-planes-experts-say-idUSKCN1R322M

[@martin1966]

“perfection” is too little to describe your effort and work. thank you. hats off.

[@YurLord]

Started following you since Oroville Dam first cracked. I appreciate how informative you are about all these matters from airplanes to wildfires to infrastructure.

[@airlinena]

Thank you very much for the update sir! I really enjoy your videos! 👍🏻🧔🏻

[@beastman.330]

Thats a cool beard, you look like a Viking

[@airlinena]

@@beastman.330 thank you very much! ✌🏻🧔🏻

[@peneumeier]

Great segment Juan! I'm an aeronautical engineering for almost 40 years and who works for a major Boeing competitor. This explains much more about MCAS, how it works, the evolution of the 737 and why Boeing thought they needed it on the newer variants. Keep your segments coming, they are definitely worth watching!

[@maxium4x4]

You have done a superb job explaining these latest crashes which is a bonus. I originally started following your updates on the spillway and never realized your flying background, quite impressive I must say.

[@wyowolf69]

as an A&P this is BY FAR the best explanation I think I have ever heard about anything! outstanding!

[@comlbbeau]

Excellent presentation. I wish my ground school instructors had your linguistic and technical skills. Retired pilot - DC-9, B-727, B-757, A-320, A-330.

[@danmekeel7758]

Excellent Job! The wife and I understood it the first time. The Umpire seat has a different perspective also, good point. Very well explained to civilians.

[@catherinenelson4162]

Thank you Juan. I appreciated Mr. Sullenberger's statements regarding the Boeing/FAA possible, (or likely) conflict of interest also. It's a nightmare situation, and I'm sure it's hard on most, if not all, commercial pilots. My best to you and your loved ones.

[@ethanpoole3443]

Thank you for providing more detail on the MCAS issue and explaining in greater detail what the pilot’s point of view is during the event as it certainly helps to answer some of my questions and addressed some of the aspects that had puzzled me.

[@cember01]

Wow, Juan. I usually try to stick to relevant questions & let other heap praise on your well done reports. But I'm just blown away by this one. To say it's a lot of very good information in one posting would be a gross understatement.

[@ivannavaro1125]

Juan, congratulation for your explanation; this is becoming the go to channel when someone wants to get facts (not only aviation-related). About the MCAS and its implementation, I am at a loss to understand how such a system could be conceived for use on a commercial aircraft. My company creates process control system for industrial applications (not for aircraft control) and one of the first thing we do is consider the consequences of a failure in a non-redundant device. When the non-redundant device to fail is an actuator (output device), failures are usually relatively “easy” for a human to comprehend and if possible to correct: often the device won’t move, or runs away in one direction, usually remaining consistent in the malfunction. When a failure occurs in a non-redundant sensor (input device), the control system takes an active role making supposedly “smart” actions, that end up being wrong in a way usually difficult for a human to comprehend, let alone correct; in this situation, I often see people frustrated, struggling to focus and unable to take the proper corrective actions. Just to make this clear, I’ve seen this even when the operator was neither at risk to get injured, nor at risk of injuring people, nor at risk to cause major equipment destruction; simple things such as fear of operation interruption, can trigger this reaction. To mitigate this potential issue, we think about input devices failure mitigation even when we are dealing with non-safety-rated industrial control systems: redundancy is usually the best, but there is also the possibility to evaluate the input signal(s) for congruence with other input(s) or even output(s): using a car as an example, if the engine is running, the transmission is in gear, the accelerator is pressed, the engine rpm shows 4,000, etc., you cannot safely assume that the car is stopped just because the tachometer shows zero; you might not know exactly what’s wrong with the car (because of the conflicting indications), but you should not take a potentially unsafe actions simply basing it on the tachometer indication. Applying this to the MCAS, since the plane already has two AoA sensor, start by using them both; additionally, consider in the decision making the signals of other sensors (such as the airspeed, VSI, altimeter, etc) and also pilots actions contrary to the decision assumed (i.e. include pulling on the yoke to cancel MCAS, and DON’T automatically turn it back on with no warning after 10s) and consider all this before pointing the aircraft nose down and applying full thrust. The fact that the MCAS has been designed with apparently no concern for the possibility of a single input failure, the fact that it has been given so much authority and the fact that it has found its way onto a production commercial airliner (to make things even worse, without proper documentation), shows a major breakdown in the decision-making process and quality checks at several levels within the plane manufacturer. I can’t even blame the FAA for not having being able to spot such problem during certification: a certification agency cannot sift through tens of thousands of lines of code to find exactly how a sensor is used, if there’s any bug, and how the code is processed, eventually asking the manufacturer to correct deficiencies. Quite simply a system designed like the MCAS has been described, should have never been used on a production commercial aircraft; in the case of the B737 MAX, it unfortunately did and this makes me wonder how many other “fail-prone” systems are in use today in other commercial aircraft (I make no difference between airplane manufacturers stating this).

[@gordonrichardson2972]

Ivan Navaro Thanks for the excellent information!

[@davide.burden2043]

I feel as though I have just been in the classroom of a very good professor. Thank you for the lesson sir. As far as I'm concerned, you deserve tenure. And a raise. ;-)

[@rivetjoint6355]

Thanks ever so much for the most cogent analysis and explanation of the 737 Max issues that I've been able to find. As an old RC-135 guy I've always been partial to Boeing aircraft but the Max problems have shaken my "if it ain't Boeing I'm not going" opinion just a bit. Your latest update really clarified what's going on from a commercial pilot's 'no BS' perspective.

[@sallysassa]

0:47 - WOW lucky they had the jump seat guest on board. Great report as always Juan. Thank you.

[@UncleEarl97]

Not just a guest, he/she was another pilot, otherwise that plane would have hit the ground a day or so earlier. Tragedy averted... for a day.

[@carlwilliams6977]

When Jaun was talking about the perspective of the pilot in the jump seat, it reminded me that one of the pilots in the jump seat of the 777 that crashed at SFO was the only one that expressed concern about low speed, prior to the crash, as I recall. I'd love to hear Juan talk about that crash! By the way... I'm always envious when I hear someone say that they knew what they wanted to do from an early age. I'm still trying to figure out what I want to do when I grow up!😊

[@ReflectedMiles]

I am just left mystified by the whole thing. The potential for stabilizer runaway events has been there since the advent of electric stab trim. The procedure for a runaway event, including two readily apparent, easily-accessed set switches, has not changed on the 737, so far as I know, for decades. Obviously the MCAS system needs some correcting, but the media frenzy over Boeing and the FAA seems to be missing the known facts entirely. If a crew of a MAX or a non-MAX airplane doesn't know how to stop a runaway event, and I do without ever having been rated on a 737, what does that strongly suggest the problem is? Maybe the same one that has attended developing-world airlines for decades, except this time it has proven to be true despite having new equipment as well?

[@bwinmaine]

@@UncleEarl97 Actually he saved that plane only about seven or eight hours before it crashed. It was a short midnight to six AM turnaround despite maintenance issues.

[@bwinmaine]

@@carlwilliams6977 Haha yeah me too and I just turned 70

[@Sovereign_Citizen_LEO]

Thanks Juan (as always) for the updates from a pilot's perspective/knowledge, and also for the personal history. A lot of people in this world are in love with aviation and want to become pilots but never get that opportunity. So it's interesting when you relate your personal life and career experience as it relates to aviation. As some people have said, I think you could easily be an aviation analyst like John Cox (among others) for the media or aviation TV shows/documentaries, voice over/narration, etc. (maybe after you stop flying commercially). And your analysis of the importance and relevance of a 3rd pilot/jump seat/flight engineer, etc. is totally on point. I really think the airlines/ FAA/ NTSB, etc. should take information like that into serious advisement (and maybe software/AI developers could attempt to replicate the 3rd party human aspect of it [somewhat], into future flight computer designs to increase overall system redundancy/safety, since they will never require 3 pilots for all commercial flights). As for Boeing, and the FAA, they really screwed this one up bad. The death of more than 300 people was seemingly quite preventable had Boeing not been so concerned about rushing the Max series to market. This to me is maybe your best video ever. Now if only the rain would clear up :)

[@blancolirio]

Thanks Skyline!

[@faris7000]

Not a pilot here, but a keen observer. This is a great video that lays out the facts in a clear and simple fashion, something other news outlets have failed to do, so thank you Juan. It is a clear case where fatal accidents could have been prevented by simple but effective measures. Commercial priorities have simply obstructed a systematic approach to pilot training updates in the face of a major overhaul of the 737, leading to these tragic air accidents. This is not just another iteration of the 737 design but a major leap in engine and software that should have been treated as such.

[@rodgerball6149]

Excellent report as always Juan. Factual, informative and no "sky is falling" hypothesis statements. Wish the big news agencies had your level of professional journalism.

[@TakeDeadAim]

I well remember flying the old -200 series with the "salami" engines slung directly under the wing. Very nice explanation of the basics of MCAS.

[@TakeDeadAim]

@@eugeniustheodidactus8890 We called the original engines "Salami" due to their appearance. They were long and relatively thin(non bypass JT8D) powerplants in comparison to the later engines on the "classics"(-300 and up).

[@snowgorilla9789]

As a mechanically inclined non aviator your vids make it easy to understand some very complex issues

[@andrewkeeney701]

Really glad that I came across your videos. Excellent presentation. Thank you for taking the time to help us understand the ongoing situation. Best, Andy K.

[@Supernumerary]

Juan- You are performing a great service to engineers, pilots, A&P’s and the flying public. Thank you.

[@vlili4385]

Really Really Really great work. Even for those of us who arent in aviation and only watch Air Crash Investigations/ Mayday religiously. I get it. I think this is the best explanation out there. Ps i was one of those who refered to the jackscrew and Alaska Air incident. I think we got what you meant about the trim.. its just we didnt get how the system fully pushed the nosedown and why pilots couldnt recover - which you explained soooo well here. I think for me, personally, that particular episode of Alaska Air, i felt, was the most traumatic, just the overwhelming helplessness of the pilots fighting and trying to save the plane... it was too sad. So my mind automatically went there when you said the word jacksrew - ofcouse knowing it wasnt the reason of the loss of flight of the Maxs. I hope that helps. Your series on explaining the Max was great :)) Thanks

[@TorturedPeace]

Juan wanted to thank you for the straight forward and thorough description of the issue! Easy to follow!

[@TheAyrCaveShop]

Juan, Started following you during the Orville dam spillway emergency, that was very informative, thank you. I have good mechanical knowledge both applied and theoretical thanks to my career as a industrial HVAC tech and through many hobbies. I've also had a lifetime interest in aviation and aerospace, although not a pilot , have had some Cessna seat time. That said: Your doing an outstanding job explaining the details and situations regarding these incidents. The average person should have a better understanding of whats really happening after watching your videos. The news media is generally clueless and just repeats talking points with no understanding of what there reporting. Thanks for great work your doing. I've made a few videos and know how much time and effort it takes. Again Thank You, Please keep them coming! -Dean

[@davidfearn5010]

David from the UK. that was brilliant Juan. All we need to know in one place. It shows how the different issues fit together. I am a subscriber from the Oroville days but now you are my first port of call for problems in aviation. A sensible explanation is so refreshing. Many Thanks

[@painkillerO8]

You are my reliable source of information when it comes to Aircraft crashes.

[@Sweetteawillie]

Excellent explanation. Also, thank you for your service to our country. Like we we told in training, most air saftey regs were written in blood. From an old Navy aircraft mechanic.

[@lesterstanley7019]

Thanks again Juan Juan, would you be interested in my recovery and survival of an total elevator disconnection at 50 feet after take of in a BE58..?? Hearing your thorough and comprehensive explanation has reminded me of the terrifying low altitude fight for survival that I went through for 45seconds and crashing 1.5 kms from takeoff.... Aircraft was totally destroyed but the cabin was intact and we all survived with no injuries.

[@Swallabat]

I sure would...

[@lesterstanley7019]

Swallabat ......Juan do you have an email address I can send info and pictures....??

[@lesterstanley7019]

Swallabat..... my email is, [e-mail]

[@GNX157]

What is the NTSB report number please?

[@lesterstanley7019]

GNX157 ......Hello, in Australia we don’t have NSTB just an incident or accident report. This incident happened in out-back Western Australia near Lenora July 1 1986.

[@victoriacironecaswell2609]

I just want to say this was a very thorough explanation of the technical issues on MCAS. I too researched and my heart was broken when I learned what truly happened in those cockpits. This HAS to be every pilots nightmare.....the pilot fighting a computer system. I am horrified when I found all the shortcuts taken to get this plane in the air. 737-800 pilots were not required any additional training for the MAX 8s.......this was a great sales pitch and savings for buyers.......but look at what cost!!?? It is good to see FAA in the hot seat AND Boeing....(who's employees are permitted to do their own inspections..a serious conflict of interest)who should KNOW better that saving time and costs should not replace safety. This new MCAS was barely mentioned in the flight manuals IF at all... and the pilots were not required any flight training time at all!?? Not to mention the flight on the day before had to be terrifying experience for the 2 pilots flying.... the jump seat pilot turning off the MCAS...Red flags!? What can you do when you don't know the system is going to consistently push the nose down drastically when it "Thinks" your in a stall.....AND accelerating......just a nightmare......and to know the system is accelerating to the ground....(I am heartbroken and sickened to learn this) I did enjoy hearing your credentials and how life has taken you in many directions. I don't know why you were not chosen to fly the fighters but all the training and variable knowledge that you do have is very valuable! Best of luck and getting back into the skies soon......God Bless You and all other pilots and crew members of these 737 series..........

[@spaert]

My dad's first plane was a Taylorcraft back in the late 70's. He loved that thing. Puts lots of hours on it and it was the first plane I ever flew. He finally sold it to buy a 172 and later a Bonanza for family flying but always regretted selling the Taylorcraft. He's 82 now and lost his medical because of a heart attack, but he knows exactly where the Taylorcraft lives. Has followed it around all these years. His health is good now and occasionally he'll talk about getting a sports license and buying it back. The owner doesn't want to sell and I'm not sure dad is all that serious about it. When he had the heart attack and subsequently sold the Bonanza, he had around 6,000 hours and I think some of the fun was gone at that point. But the passion returns occasionally now that he hasn't flown for some years. And it's the Taylorcraft that rekindles it. Great video and good recap on the update. Thanks for sharing!

[@Mark-zb8fi]

You are absolutely the most amazing orator I've ever heard when it comes to explaining in detail not only human factor considerations but wide-eyed specific aircraft knowledge.

[@warrenjones497]

It’s hard to visualize the terror the crew experienced when struggling with the MCAS. Fear definitely compounded the difficulty of coping with the emergency.

[@JohnWLewis]

Yet another excellent report, Juan! Keep up the great work! You provide a very good description of the tunnel vision when faced with handling an unexpected situation. I'd add that not only is one's "picture" restricted in lateral/subject scope, but also in time. One's time horizon collapses, so one cannot see very far down that tunnel! The first time I was faced with an aircraft malfunction, I experienced this effect. (Before that incident, everything that had gone wrong during my flying had been my fault!! So that was the first mental hurdle!) I'm a low hours (and now long lapsed) private pilot (350 hours in total, and less at that time). I had a pitch trim malfunction in a TB20 (Trinidad). It was not even a runaway, it had simply jammed. Even so, when climbing out, as I unthinkingly routinely cleaned up the aircraft, increasing forward control force was required to keep the speed from falling too low. Also routinely, my thumb was planted on the electric trim switches, but this was having no effect. As you describe, a pilot who is not flying maintains a broader perspective. Luckily my front seat passenger was an instructor and examiner, who immediately recognised that I had a problem. After we'd made a fairly quick diagnosis of the problem, he asked me whether I wanted to turn back, which I did. Later when we discussed the incident (which, by the way, was caused by a riding turn on the cable drum), he asked me about the decision to go back and whether I'd already thought about that. My response was that I had not thought that far ahead!! Before takeoff, my time horizon had been approximately the duration of the planned flight, about an hour and a half. That fault caused my time horizon to collapse, probably to less than ten seconds!!

[@blancolirio]

Excellent example! Thanks John.

[@aerojp4]

Excellent very informative report Juan! You answered the simplistic thought I had of why didn’t the pilots simply cut off power with the Stab Trim Switches. You gave a good perspective on the nature of the urgency of what’s happening, the conflicting information they’re getting, and the limited time to react. Thank you. Keep up the great work.

[@davidcarroll8735]

Ron Grossjan Agree, similar to the portrayal in the move Miracle on the Hudson, if the simulator crew was told what the problem was beforehand, they could return to an airport, if they went through the full diagnostic process and time elapsed, the only correct choice was the Hudson.

[@JRP931]

I really liked your input about having the perspective from flying in the jump seat. 19 years ago I started at a Part 141 training facility and got up to my single engine commercial with instrument rating (quit pursuing flying as a career for outside reasons after getting commercial). As part of the 141 program, they required a set amount hours of back seat time, watching another student and instructor. I am not sure if it is an FAA requirement under 141 or the institutions policy and procedure but I learned just as much sitting in the back seat and helped me understand things that I was not getting while up front. Best part was I wasn't getting charged for the instructor or the aircraft time.

[@DirtBikingwithDonnie]

I'm really enjoying the level of information you are providing in these videos. I don't normally comment because it's already been said, but felt compelled after this video. Well done. I found your channel when you were talking about a KTM dirt bike, but I find this information very interesting. Thank you.

[@yumpinyiminy963]

Your comments are right in line with everything that I understand and heard about the 737-MAX. There is always a ladder of mistakes that add up to a crash. A lot of missteps from Boing, FAA, Training and Pilot error. My sympathy for all the family members that lost loved ones.

[@nekeke1]

Thanks for the update. For me, it is really unbelievable that an aircraft like the 737 is relying on just one alpha probe for that critical system; even the humble turboprop ATR is always comparing the two AOA vanes always to compute the activation of the stall protection system; it self disables (advising both visually and aurally to the crew) when the difference between both of them is above a certain threshold. How in the world could Boeing implement this system reliying on just one alpha probe?. NONE and I mean NONE of these accidents would have happened if the system were constantly comparing both of the AOA values instead of just one. Shame on Boeing and the FAA. By the way, I'd say exactly the same if it was Airbus or the EASA. Please, stop blaming the pilots, as they didn't have the room or time to correct the situation, regardless of their training or experience.

[@yumpinyiminy963]

I do not know what happen. Anything is speculative until the official release. Read my statement again and you will see I did not blame the pilots. It is never 1 thing that brings a plan down (9/11 excluded) it is usually a combination of things stacked on top of each other. Being a pilot or even a stuard used to be a well paid glamorous jobs or at least perceived that way. Only senior pilots on major airlines actually make anything near what they should for the training and responsibility they have. If it was the Mcas system and the recovery action is to turn it of and go to manual flight. Even if it is trained as a memory reaction, there is too little time at that altitude to understand the emergency and react. My statement was in general for air disasters.

[@SmittySmithsonite]

We couldn't get 1/1,000th that type of information on the mainstream news! Appreciate you taking the time to thoroughly explain this MCAS system. 👍👍 Sure makes me wonder if Boeing will be sued big-time by the families of crew and passengers of those lost thus far. From where I'm sitting, they engineered a death trap, especially by not FULLY explaining this system and how it functions. I recall not long after the Lion Air disaster, American pilots were asking alot of questions about this system, and weren't getting very many answers. Seems to be a trend in manufacturing today, where the manufacturer wants to keep everything secret. That may work for a while in land based machines, but there's no "do-overs" in aircraft at any altitude, especially lower. Thanks for the great insight! 🍻

[@gordonrichardson2972]

Smitty Smithsonite The airlines insurance will pay out most passengers claims. A few may try to sue Boeing.

[@bobcaddell7145]

@@gordonrichardson2972 Airlines may sue Boeing

[@Tom44224]

@@bobcaddell7145 Norwegian has already started.

[@jhschmitt44]

I appreciate your updates. I’m a retired UAL B747-400 Captain, former US Navy pilot and FAA Aviation Safety Inspector. I have more than 22,000 hours of total flight time in the DC-10, B727, B737, B747-400, B757, B767, CE-500, SK-61. During my career at UAL I was Vice-Chairman of our ALPA Central Air Safety Committee and ALPA Chairman of our FSAP Committee. In that capacity I was part of the UAL Accident Investigation Team. I have one problem with this entire discussion. There has been no discussion of the basic lack of basic stick and rudder skills. We have all been taught to turn off all of the “magic”, autopilot and the autothrottles, and hand fly the aircraft when everything heads South. In the Ethiopian accident N1 was left at 94%. I wonder what would have happened if these pilots had reduced their thrust, turned off the autothrottles, autopilot and pitch trim and flown the aircraft manually? All of the “magic” will take you places you don’t want to go and fast! Keep the updates coming, they’re greatly appreciated. JH Schmitt

[@SmittySmithsonite]

@@jhschmitt44 -Thank you for your service! Great points you make there, too.

[@bcrazyyeti]

Appreciate your "Pilot's Perspective" on this and the background on your years of experience. Seems like Boeing has made a ladder of mistakes that have added up to 2 disasters that could have been avoided. As always you tell complicated stories in a very clear and engaging manner, Keep up the great work.

[@OCnStiggs]

Juan, Great discussion, as usual but, a couple corrections based upon the latest information available to 737 customers... MCAS is NOT a system. Technically, it should be called "software", rather than system. It's a few lines of extra code in the elevator feel computer that simply makes the MAX fly like the New Generation aircraft. Note: (and its a biggee) The MCAS DOES NOT and never has been triggered by a stall condition. It is solely designed to counteract a pitch sensitivity encountered when the MAX is flown at high bank angles (excess of 45 degrees) where the elevator gets very light and sensitive. Think "extra power steering." The MCAS software restores extra load to make that sensitivity go away. The MCAS trims the stabilizer for two seconds, followed by a ten second delay before another two seconds of trim. Remember, with flaps up, the stab trim runs in "slow" speed. A runaway MCAS problem is totally resolvable by simply manually trimming the opposite direction until the STAB TRIM motors are switched off or the trim wheel is manually held. So far, all American carriers have DUAL AOA vanes installed for the MCAS input. A single failure will illuminate an AOA DISAGREE light in the cockpit. The Lion air and Ethiopian flights had single AOA vanes installed. Boeing ran many failure mode tests on this system and never saw the failure mode experienced by the crashed carriers. As you pointed out, the Lion Air aircraft was successfully recovered the day prior to the crash by quick input after suggestion by the jump seater. Simple system knowledge saved that aircraft that day. Lack of that knowledge doomed the same aircraft the next day. The MCAS failure scenario is not instantaneous and any competent pilot hand flying the aircraft would instinctively fight an unrequested nose down trim with opposite trim until the cause was determined and isolated. Keep up the great work. -Retired with 22,000 hours of 737 time.

[@gordonrichardson2972]

OCnStiggs Useful feedback, but some inconsistencies. MCAS trims down for a maximum of 10 seconds at a steady rate of 0.25 degrees per second, followed by a 5 second pause. All 737s have dual AOA vanes, the issue is whether the numbers are displayed to the pilots. Juan has read all the updates, though there are still several unknowns.

[@daveuggla8383]

All of the planes has two AOA sensors, one on each side. But only one was actively used by MCAS at a time. The optional AOA display (both sensors) and the Sensors Disagree light were the optional extras. If the pilots did not take note of the display and light, the MCAS operation would be totally unchanged.

[@RealDavidN]

Another excellent effort. Thanks for the detailed analysis from a pilot's perspective. In particular your discussion about how the MCAS failure would present itself compared to runaway trim, and how the startle factor affects the pilots. I'm pretty much ignoring news coverage, waiting to see what Juan says about it. Thanks from a "bugsmasher" pilot. That and your "convinced me to cut my hair" comment made my day.

[@gavinfinlayson485]

This is fantastic, far and away the best insight into the complete 'story" so far. Fascinating technical knowledge and conveyed in a way which is easy to understand. The stand out channel on aviation by far. Top marks Sir 👌

[@GH-oi2jf]

This is the most thorough discussion of the whole problem I have seen yet. Thank you. I listened to the whole thing. One point of controversy still being discussed is whether putting these more powerful engines on an old airframe, requiring (for some reason) automated trim adjustment, is in itself a design error. I am sure that MCAS can be made safe, but should it have been done at all?

[@richardbradbury2851]

Excellent coverage, logical thinking and great explanations! My dad designed the auto pilot in the original 757 / 767 (that alone was a billion dollar Boeing contract around 1978) and I think he’d be mind boggled by Boeing’s lack of redundancy in the AOA indicators feeding the automation systems. I remember sitting at breakfast and asking him the statistical likelihood of failure in that triple redundant system - I think it was in the hundreds of millions to one. The fact that Boeing included the mismatch AOA warning light only as an “option” is crazy. The check list should mandate matching AOA indicators for the pre-flight and if an automated system is attached it should be validated by two if not three for redundancy. Heck, all it would take is the window washer or line service bumping the one AOA with a cherry picker and you’d be finished. I totally agree with Juan in the fact that if someone’s not totally on their game and pre-trained about the new aggressive MCAS system, it would be easy to miss the trim disconnect while distracted by panel lights, airspeed, stall warnings and unusual attitudes. At -4000 feet per minute, it only took 20 seconds to hit the ground. It’s also pretty obvious that foreign carriers with lower operating requirements are a huge issue, they didn’t pay for the AOA mismatch indicator light option (it shouldn’t be optional) and even though they had an in-flight emergency the day before with AOA / MCAS, they were allowed to fly. Hence the “chain” of events. Thanks again Juan for the excellent coverage.

[@wilberburroughs3133]

Hats off to you Juan. Great explanation setting up the real stuff we see in the cockpit. Having a third guy, or gal, is golden. You nailed it. The third seater is an umpire and the pressure in not on him, so he/she thinks clearly and sits outside the tunnel vision episode where time is of essence. I´m sorry this happened, I really am, but only this type of unexpected occurrence, with fatalities, forces safety revisions. I believe Safety has taken a back seat to Economy in todays world, and I´d hate to discover that for profit, safety features are put aside. Sim training, as well, plays a giant part. If I were flying the Max, I´d make sure the PNF had his fingers close to the cutout switches. keep doing your videos. A pleasure watching them. Stay Humble.

[@jeffnielsen4057]

Great stuff, Juan. My wife and I are pilots, we sat down and talked about this one for an hour or more. I think we have it: To keep cost down, airline manufacturer company modifies a plane with new efficient engines that have the side effect of causing the plane to pitch up. To keep the plane flying as close to what it used to fly like, you add a little system (mcas) to counteract this pitch up issue. If you didn't keep the plane flying the same as it's previous model, it would cost a ton of money to retrain pilots because it could even be consider a new type aircraft. So they add this little "minor" trim device to counteract the extra pitch up so they don't have to label this plane as a new plane/type, essentially. RIGHT? Failure happens because of inaccurate information from the angle of attack indicator/electronics reading a high angle of attack relative to the wind and the jack screw positions the horizontal stabilizer to put the plane in a dive position. At this point, full movement of the elevators can not negate the effects of the horizontal stabilizer position. (and yeah, one fix of that could be just to limit how far it can pitch the stabilizer and still have the elevators be able to overcome that aerodynamic pitch) How did we do? We think that the extra pitch up issue must be significant because all pilots would know how to control the nose of an aircraft as you climb out. That is fundamentals of flying, day 1, climbing out - no new training needed. However, again, we think it must come back to keeping that plane's flight characteristics as close as they can to the previous model ..... to avoid a new type certificate.

[@blancolirio]

Yep

[@robertolson483]

Been waiting for this one! Thanks for all of your great videos.

[@pomonabill220]

I am surprised that the MCAS could overpower manual override without disabling the system. I would think that in an emergency, you may not have time, or the presence of mind, to flip the switches as you are trying to correct things, and to have the MCAS be all that powerful seems like a bad idea. Also, why is the system relying on one sensor without redundancy? That seems like a bad design choice also. Thanks for the outstanding explanation!

[@chriswikeen3743]

First, who gives your reports a thumbs down? Really??? I give you two thumbs up! Excellent report and this coming from a non pilot (me) but a person with understanding of flight. This latest crash was too close to home with two soles lost from the Redding area. Thank you for shedding light on this accident and helping us understand the dynamics of “what happened” on that fateful day. Fly safe Jaun and I look forward to someday meeting you. If you ever want to land at Lake California airport, you will be my guest.

[@johnschmid3151]

Great job Juan! You provided an enormous amount of facts and background information here in a manner easily digested by those of us who are not pilots. Your sharing of the “startle” factor was particularly illuminating for me.

[@raydaley2597]

Thank again Juan, always on top of events with a pilots perspective. Really appreciate your top news updates. Your presentations are right on for this old time clod buster and the sound is perfect. RD, Queen Creek, AZ

[@killcrashkill]

My wife was very concerned about the 737 Max. Thanks to you, I was able to explain to her, what the possible problems were and why we would not be flying on that aircraft next week. My father was a aircraft accident investigator, during WWII and he helped me realize that in most accidents there is rarely one simple cause. You reminded me that accidents are usually the result of series cascading events. Thank You Randy p s Luscombe fly-by-wire = LoL

[@bighaasfly]

Exactly right. The third nonflying member is like being a flight instructor. It’s easier to critique the student than it is to fly the plane yourself.

[@370Scotty]

I can't express anymore thanks, than the other posters! You've got a Second Career ahead of you in Flight Training, and 'Real' Journalism!

[@neknosnaws5990]

Thanks blancolirio, for explaining several points for which I needed clarification and explanation...! Re: Redundancy of AoA sensors: It is my understanding that Airbus uses 3 AoA sensors, so that in the event of a single sensor failure (the most common scenario) the flight control system will use input from either of the two sensors that AGREE with each other, as a failure of two sensors at once has the LEAST likely probability. However, two included sensors are enough if MCAS is not flight-critical, and if it shuts off if the two sensors disagree, to be repaired later on the ground. However, if the MCAS is critical to avoid stalls in the 737 MAX then 3 sensors installed with isolation circuits (so that a 2 sensor failure is least likely) would be the safest. At this point, we have to acknowledge the comments of Sully Sullenburger that it is still important that cockpit crews can fly aircraft manually when systems such as MCAS fail, and are trained thoroughly on how to disable non-functioning systems. Also, the Seattle times has pertinent information about the dialogue between the FAA and Boeing, with regards to the safety certification of the MCAS system, which is still relevant: www.seattletimes.com/business/boeing-aerospace/failed-certification-faa-missed-safety-issues-in-the-737-max-system-implicated-in-the-lion-air-crash/ and a rephrasing of the Seattle Times article article from nymag.com, regarding Boeing self-regulation: nymag.com/intelligencer/2019/03/report-the-regulatory-failures-of-the-boeing-737-max.html I hope Boeing gets it right before these planes fly again; not just for their bottom line, or for their shareholders, but for the 346 who will never fly again!