Boeing 737 Stall Escape manoeuvre, why MAX needs MCAS!! 

Very interesting!. Learned more from you then any news outlet. THANK YOU

You can see just how uncomfortable both pilots felt with the "airspeed" verbal warning, even though it was only a simulator. He wasn't kidding, that warning definitely wakes him up.

Looks like doggo was experiencing some uncommanded roll!

“You’ll get ‘BUFFET ALERT’. Now this warning has nothing to do with food.” Total deadpan delivery. I see you Mentour! Hahaha

lol "buffet alert has nothing to do with food"

"i know i've made some very poor decisions recently, but i can give you my complete assurance that my work will be back to normal... i've still got the greatest enthusiasm and confidence in the mission, and i want to help you." HAL - 2001 a space odyssey

Mentour Pilot - The place for accurate, unbiased aviation knowledge. Thank you.

I am retired Boeing and have worked on the 737 project almost twenty years. You have explained the system and characteristics better that than anyone could.

From the Seattle Times, “The newspaper said the analysis also failed to account for how the system could reset itself each time a pilot responded -- in essence, gradually ratcheting the horizontal stabilizer into a dive position.”

Really great video! I'm not a pilot, just a big time aviation enthusiast. You explain everything so clearly that even a non pilot like me can understand. Thank you so much!

I think the root of the problem is that the MCAS continues to be active even when AOA and Speed are unreliable due to damage sensors or other defect. In Airbus there is a degradation in protecions when the aircraft is in a degraded flight law due to some failure. So basically the airbus is like "I am broken, you need to fly alone" and the Boeing "I am broken, but will continue to act like I am working"

I really hope all pilots are like you because I'm flying for my first time ever in 3 days

I couldn't take my eyes off that cute pup! 😍

Exactly the video I've been waiting for. Great work!

Mentour, I work as a mechanic for an airline in the US that currently has several 737 Max 8 in their fleet. I was just looking at the maintenance manuals, did a search option and found no mention anywhere about the MCAS system. Interesting.

I trimmed the B737F-200 and 300. The engines on the 300 was the first plat bottom versions. Then it was already so nose heavy that it could not fly empty. It needed at least 1800kg of ballast in the last two positions to take off. Granted the cargo door was heavy and also had to be placed in position A because the engines was in the way of the FMC. It could only go down hill from there with bigger engines in later versions.

You and Juan Brown (Blancolirio channel) are the best Pilots in the world when it comes to explaining things with no BS and undestandable to both Novices and laymen alike.

"I'm not going to go into the basics of a stall" ... IMMEDIATELY explains the basics of a stall 🤣😂🤣😂

I really wish journalists would watch videos like this before writing their articles. Really well explained and presented.

Im a current 767/757 pilot, and former 737 pilot. Very good and comprehensive explanation ! Well done sir.

I saw in another video that the 373 MAX basically introduced a physical alteration as a result of adding larger engines -- An upgrade that Airbus did on its I think A320 model shortly before. The problem was that Airbus had higher wings and could fit a larger engine under the wing. Boeing 373 wings were lower, and the engines already were as low to the ground as possible. Therefore, they had to raise the larger engines into and over the wing, which had a destabilizing aerodynamic effect that pitched up, raising risk of a stall. The solution to this (seemingly in replacement of additional physical stabilization, but I'm not sure) was the MCAS system, which was software intended to counterbalance this physical deformation induced off-balance. This software had a bug..... And we all know the result.

That is what I call professional and accurate information! Thank you Mentour!

Big detail regarding the MCAS function: The MCAS only uses a single AoA sensor to determine if the aircraft is in the right flight profile, and the pilots can select which of the two AoA sensors to use. Discrepancy in the two sensors is not detected by default (it was an option *that had to be purchased*) and even the display of the AoA readout on the PFD is not enabled by default. On the Ethiopian Airlines craft, the AoA sensors were reading 3.2 and 7.2 degrees respectively, which would in any normal case be a condition to trip on a sensor failure and disable the control system entirely, which did not happen. There is also no cross-checking of the AoA reading with all other parameters of the flight profile, like airspeed, rate of climb/descent and attitude to determine if the measured AoA was even in a plausible region. The MCAS just blindly followed the reading of any sensor that it was connected to, regardless of it working properly or not. The software update issued by Boeing actually enabled discrepancy checking and the 'AOA DISAGREE' warning on the EICAS for all 737MAX models.

Sounds like a design change (moving engines) that resulted in the plane's stalling at full thrust if left to its own, so Boeing put in automation to pull the nose way down. Automation pulled the nose way down when it didn't need to do so, and the pilots didn't have enough time at low altitude to figure out what was going on and how to fix it before it hit the ground. Sounds like a good call to ground this plane!

What is truly unconscionable is that Boeing didn't put out a general advisory - after the Lion Air crash - or seem to address the problem in any way. The lives lost are on Boeing's head.

Glad to see the dog getting some attention this time! 😉

the stick shake and warning makes you nervous even in the simulator. its scary

How can you not pet that dog when he rolls on his back like that? He clearly wants to be in on the action. Love the vids. Thank you.

He holds up model airplane at 4:18. Doggie says, "Chew toy!"

Been waiting for this! Thanks for this quality informative content. Friday highlight😜

Yes, this is exactly the video I wanted to see!

Doggie is living his (her?) best life!

Great video. I've been flying small planes since I was 16, and it's always a pleasure to listen to someone who really knows what he's talking about, and can relate it clearly. It's also very obvious why there are fewer than 300,000 airline pilots in a global population of 7 billion plus.

It seems the real issue is that MAX aircraft do _not_ react the same as other 737 variants, exacerbated by different behavior of autopilot _off_ behavior when pilot jerks the stick compared to other 737 variants. Clearly these differences would imply more and better training of pilots on MAX, even if they are previously certified or experienced with 737. But Boeing specifically indicated such extra training was not required (clearly, so as to make the new MAX a better economic proposition to airlines). The MAX does _not_ fly or react like other 737s at and near the stall limit and the MCAS fights with the pilot trying to push the nose down. If that pilot is just coming from hours on another 737 model, they might instinctively react in the wrong way on a MAX. At 30,000 feet, perhaps not an issue. At 2,000 feet? Catastrophe. I'm sure Boeing will continue to tweak and improve the MCAS software, but what really needs to happen is for pilots to better understand that MCAS-equipped aircraft are _not_ like other 737s, and adjust their procedures accordingly.

The puppy is so high altitude of cuteness😁😊😀

The red and green "navigation pillows" always make me giggle 😁

Stall training was definitely the most unnerving part of training so far. There's a lot of warning signs prior to a stall, but the actual stall itself is rather sudden. It tends to induce panic so the first thing you have to do is learn to not panic, and remember the stall recovery maneuver. Stalling an aircraft on purpose (which is done in training and sometimes for aerobatics) is somewhat different to when it happens unexpectedly though. A regular stall, from what I experienced isn't so bad, but the second thing we trained was an accelerated stall. That surprised me enough that I tried to recover before the instructor had finished inducing the stall in the first place. The main thing that made it a lot more disturbing than a regular stall is that in the aircraft we were training in, an accelerated stall causes one wing to stall before the other. Since this makes the lift asymmetric, the aircraft quickly rolls on it's side within a second or two. Rolling sideways rapidly when you're not expecting it is not a pleasant sensation... Unfortunately I had to stop my flight training for financial reasons and it was quite some time ago, so I may be misremembering some aspects of it. But in general the idea is to pitch the nose down and increase thrust. And if you experience a wing drop use the rudder to correct it, not the ailerons. I'm sure it varies by aircraft, but the general idea of it is that the wings and tail are designed such that they shouldn't both stall at the same time. Thus you should usually be able to recover using the tail. Engine thrust may be something more specific to single engine prop aircraft, since the prop wash increases airflow across the wings and tail, which should increase control authority. (it also induces roll, but that's not directly relevant.) - worth noting that the specific aircraft I was doing this training in had a stabilator, or an all-moving tailplane. The trim actually adjusts a seperate flap on the horizontal stabiliser, while regular stick movenents cause the entire horizontal tail surface to move. This is the opposite to the example shown in the video, and no doubt has somewhat different implications in a stall (though I'm sure the general principles remain the same.) Again, I could be remembering this incorrectly at this point. I've only had a few hours of flight training and it was several years ago now. Still, the experience of stalling an aircraft and trying to recover from it is not something you forget easily. XD

"Lose not thy airspeed lest the ground rise up and smite thee,"

I love that dog, its always patient ,thanks for the video,well explained..

Loved your comment about “buffet alert” - “nothing to do with food” 😂

Wow amazing detailed explanation of Stalling and the difference on NG and Max great job 👍🏽

Very clear and very helpful. Thanks so much!! - Dean from cold Minnesota

MCAS=(may crash any second)

Not only interesting but also so clear and simple explanation. Thank you so much, you're a great teacher!

I love your videos sir ,keep it going 🙂🙂.all the best to you🙂.

Ahaha the doggie and the remote 🐕 Good timing 😂

wow. great explanation as always after so much confusing info in the press. thank you for covering this. great job, as always!

Very informative as always. Thank you. The best

Mentour, you are THE MAN!! Fantastic video!

Mentour Pilot/Petter Thank you very much for this video and all your videos! I have been watching your channel for a few weeks now and am a new subscriber and appreciate all you do to explain things about the airline industry, aircraft, and piloting. I am in the Boston USA area. God bless Paul

Great Vid! I needed this explanation. Love the CO-PILOT DOG very cute.

Great video and explaination; thanks! I believe that I understand and agree with the need for and design of the MCAS system, since the MAX versions are perhaps more difficult to wrestle out of an imminent stall, but what I do not understand, following the malfunction and crash last October, is why there was no IMMEDIATE RETRAINING for all MAX pilots to make sure that they could sucessfully disable this MCAS system if necessary. I feel that if Boeing and the insurance groups had endorsed this response, any future occurance of an MCAS runaway would have been non-fatal, and would have given ongoing data to the software engineers to allow them to eliminate this errant behavior from the system in future updates. Cheers!

You explain very well and I understand most of it. Good job@

I know this is really serious and all, but your dog is freaking adorable

At almost 50 years old, these videos make me want to pursue my childhood dream of becoming a pilot.

..thanks sir, for your explanation about MCAS

I have been wondering about stall since I was a kid. Finally explained

Best aviation channel on RU-vid. When I next fly abroad, I'm going to insist that I'm on one of your flights!

Thank you for a clear explanation. I like that you take time to explain and demonstrate this concept. That combination is gold!

Thanks for this excelent video. I've been in flight training for twelve years, and can't remember this issue on the 757 of 767 (only verry little irilevant experience on 737-400) Then again, as you describe, the 737-MAX is morely a total new airframe that just has the looks of its predecessors. Having lot of experience in instructing on different types i can off record imagine what has been going wrong. Mentor Pilot, you'd be an instructor of my heart.

Thank you captain for this informative video.

I love the doggy so cute, thanks for a great video, from a cabin crew , fly safe.

Thank you for explaining thoroughly the basics of MCAS system!

Well i learned something today and that is something I try to do mostly all the time so very informative,thnx

13:40 Elton announced "stall stall", now that's training! He didn't hesitate.

Thumbs up if you want to have Mentour as a flight instructor ! Sir you're brilliant, passionate, and there is evidence that you like your fans and your job and this leads you to bring amazing content

Hi Mentour, l just found this in my YT watch later list. l've always found your channel to be really interesting & informative. ln this video l did cackle when you said 'buffet alert - this is nothing to do with food !'. 😂😂😂

And I love how you say, “the 500 first of you.” It sounds wrong but smarter at the same time somehow. The accent seals the deal. 👍

Excellent video and explanation of MCAS

The dog STOLE the show :P

love your dog :-) great video and very informative. thank you !!

OMG look at that adorable DOODLE! Best part of the video.

Great video, helps understand the issue. Thumbs up for the couch co-pilot.

Very cool video Mentour i enjoyed it, have a good weekend my friend.

Excellent explanation, even better dog! :-D

Man I got used to seeing videos on this channel with the dog lying on the couch, asleep. Now, the dog just stole the show early on. LOL

first officer smilling while deadly stall hahah cool

Great explanation of stalls and why MCAS is there. This DOES mean, however, that if properly trained these accidents (at least the Lion Air accident) should not have happened. MCAS should be turned off by the pilot.

Another great episode, working my way back and all the answers to things I’ve wondered about!

Really reassuring videos man!! Keep up the great content... I have a lot of respect for what you do for a living :)

MCAS biggest flaw is their failure to give AUDIO and VISUAL warning to the pilots when it is activated, at LOW altitude any pilot will panic as the plane goes nose down without any warning and they had to fight to pull back while trying to figure out what caused it to dive in the first place. Secondly Boeing did not put a specific training on how to disable this system, because when pilot try to fly the plane manually, it will still dive! Thirdly equipment can malfunction and give wrong readout so they need redundancy, not just triggered by just 1 sensor like in Lion Air crash.

You looked really rough during your live stream. You brush up very well. You are like a different man.

During my days of flight MCAS stood for Minimum Controllable Air Speed. Just LOVE all the acronyms of aviation!

Thanks, Mentour Pilot; clear and concise as ever! BTW, I think your dog stalled towards the end.

Thanks for the lesson on Bernoulli's principle. A stall in a plane is like a stall in a car. They both stop moving. The big difference in stall training in the 172 is that when the plane stalls , you'll get a wing drop, nose drop and its relatively gentle. When you stall a 73Max the whole plane drops. A good example of stall is 06:10 when your dog is laying on the couch, stalled and looking for a belly rub!!

Blesses you mentour pilot of the whole world" always be well and careful😊

Thanks for the info! Love your dog too!

Mentour you are my most favoured pilot on social media! Very informative and entertaining as always.

Thank You for your knowledge and professionalism, the Aviation Community appreciates your explanation of the probable cause of the most recent Boeing 737 Max 800 airline crash. Continued success; Cheers Gary

You made the simulator stall recovery look easy. ;-) Very nice demo! I'm sure it's a LOT hairier when in flight though. OK.............. back to my internet browsing.

First: Thx for that nice video! Amazing how well you can explain:) Second: I have some "insight" information from 737 pilots as my father is one of them. There is currently a message going around of a pilot explaining the lion air issue. Below I will share that message with you...for all of you with a little bit of background knowledge the message may be informative and interesting. From a captain friend... Boeing (and many posters) say "Hey, it's just a trim runaway. Do the drill and all is good." But this is not the simple trim runaway that the QRH contemplates. It starts with a stall warning stick shaker shortly after lift off. Close to the ground this will, and should consume both pilots undivided attention. After a number of seconds they realise that the airplane hasn't stalled and they start figuring out that they may have an airspeed and/or AOA problem. This is a second problem to deal with on top of the first. And they can't shut the &%$#@ stick shaker off once they realise that it may be spurious. The PM will be frantically scanning the panel to try and find some clue what is going on. And this whole time, among the din of the stick shaker, crews concern for the airplanes flight path, and the confusing instrument indications, MCAS has been intermittently dialing in nose down trim. Not steadily, in a calm cockpit at altitude like the QRH contemplates. But intermittently in the background of chaos, noise, and confusion. At some point, well past when it would have been timely, the task saturated PF realizes that the trim is working against him/her and the stab cutout switches get turned off. (hopefully)But the shitshow isn't over. Because of everything else going on, this took too long and the airplane is way out of trim. The Lion Air crew reportedly had 60 KG of back pressure on the yoke. Close to the ground, and relying on the lifting component of the underslung engines to help keep the nose up, the crew do not dare reduce power. Now the crew needs to manually trim the airplane, but the airplane is way, way off its trim speed. The B737 QRH makes reference to the large forces that may be required to break free a servo clutch: "3 If needed:Use force to cause the disconnect clutch to disengage. Approximately 1/2 turn of the stabilizer trim wheel may be needed.Note:A maximum two-pilot effort on the trim wheels will not cause a cable or system failure."Worse, the "Manual Stabilizer Trim" section of the Boeing FCTM talks about the air loads on a grossly out of trim stab requiring a speed change to reduce the force required to manually trim: "Excessive air loads on the stabilizer may require effort by both pilots to correct mis-trim. In extreme cases it may be necessary to aerodynamically relieve the air loads to allow manual trimming. Accelerate or decelerate towards the in-trim speed while attempting to trim manually."Sweet Jesus how did this thing get certified? A guy (or petite gal) has a 60 KG+ force on the yoke trying to stop the airplane from impaling itself into the hard ground just a few thousand feet below, and now he/she has to brute force trim the airplane as well, requiring involved coordination with the PM. Still with all the stick shakers, aural warnings, goofy instrument readings, and whatever else is happening to distract the crew and making communication almost impossible. It is not hard to see how quickly it becomes overwhelming. In addition to a fix for the airplane, if they keep the MCAS system (instead of designing a whole new wing or tail for the airplane), they will have to train the pilots who fly it to deal with its failure. Right now, there is not a single Max pilot in the world who has been trained for this failure because - there isn't a single simulator in the world that can replicate it. But when they do, all those pilots that claimed "it's just a trim runaway" are going to have a very eye opening simulator session."

Love your channel, thank you for sharing your expertise!

I loved your reference to buffet Alert not relating to food 😁😁👍

Thanx. This is will be the next thing I try in the simulator.

This channel has cured my fear of flying.

I had a basic understanding of everything you said in this video before watching it, except for one thing. It has never dawned on me before on how the engines could actually create or worsen a stall. Before this video my first reaction to a stall would have been full power. I guess in a small airplane with a nose prop, that would be correct, but with these commercial jets... bad idea. So thank you for educating me in regards to how the engines can work against you in a stall. My basic understanding has now improved.

I think what we're going to find is that Boeing tried to save costs by grandfathering in changes on a 50 year old design, with engines that should have gone on a clean sheet - and band aid a solution with the MCAS. The 737 had reached it design limits (737-100 was designed as an aircraft low to the ground, with smaller engines to accommodate an attached ladder for passengers) and as more power was needed for each new stretched version, the dam finally broke. We'll see what the reports bring...

Hi Pettr. The school where I work, gave me a VR-thing for my phone today. I can now really enjoy your Mentour 360 app. It is wonderfull. (Sorry for the off topic comment). Now ontopic: Does a Deltawing create the possibility of a higher angle of attack and stall later?

Finally someone with knowledge and ABLE to put it on screen for learning purpose. Thanks for sharing

Omg, I thought I was in love with the ginger, but that copilot! He is perfect. What I wouldn't do to be inside of that cockpit. You have not yet seen this stick shaker in action.