Why are Boeing 737s CRASHING? | In layman's terms 

Sorry AvE, Sweden never had Harrier's. Some handsome n blond Swedish dude duped you...

I was hoping for a 737 teardown.

A quote from a retired airline pilot i knew "My career was 20,000 hours of boredom and around 20 minutes of absolute terror."

as one of my pilot friends said, he became a pilot to over come his fear of dying alone

As a qualified Aerospace Engineer previously (15-20+yrs ago) involved in design of aircraft similar to the 737MAX, I can offer my perspective. Essentially, Central to the 737 MAX problems is the MCAS (Maneuvering Characteristics Augmentation System). Principally, to fit the 737 MAXs larger engines ( Larger = more fuel-efficient), The Larger Engines Cowlings can create significant lift at higher angles of attack, which can cause a higher angels of attack which. . . . aka runaway train of lift/higher-AOA. which caused the MAX to be prone to going nose up during flight in certain situations, increasing the likelihood of an unintended and unrecoverable stall. [Previously wrongly stated by me as: Boeing radically redesigned the engine mounts for the MAX version of 737. This significantly changed the plane’s center of gravity rearward which caused the MAX to be prone to going nose up during flight, increasing the likelihood of an unintended stall.] Thus MCAS was designed/implemented to automatically counteract that nose up tendency and favour pointing the nose of the plane downward in certain situations. Early reports from Indonesia's Lion Air investigation suggest that a faulty sensor reading triggered the MCAS suddenly after takeoff. It's currently being speculated that a similar event may have occurred in the recent Ethiopian Airlines crash. My understanding is that to override the MCAS isn't that hard, Primarily flick a few switches etc, but trying to do this while using both hands fighting around 100 lbs of force on the control stick (aka trying to stop the nose pointing directly down) is the tricky bit. Cheers Edited: (1) To replace the 3 uses of "Basically" with Essentially, Principally and Primarily to avoid sounding like Ivan G's Little Sister (2) to correct "a few hundred kg of force" to "around 100lbs of force" (3) to correct wrong statement about Engine reward weight.

Never thought I would hear "angle" so many times with no mention of the dangle

Someone clearly didn't put their phone on flight mode

As a retired pilot my plan was to run to the back of the plane in a crash situation and screw the first person I saw. Abandoned this plan when the co-pilot told me he was gonna do the same!

I actually welded titanium parts for the 737max. I should be good. All my welds have passed x-ray.

Hi AvE, I'm an armchair pilot with 15 years experience in Microsoft Flight Simulator. I can tell you without a doubt that the plane went down because of lag, and not an inexperienced pilot. Also, the media exaggerates the significance of the crash. The crew on board are NPCs and as a pilot you will always respawn after a crash.

As a professional pilot, I cringe when people tell me that the autopilot flies the plane. My response is always the same, “The Autopilot flies your plane about like your cruise control is your designated driver.” It’s merely a tool to reduce workload and needs to be monitored at ALL times. It is literally just a computer that does simple tasks and needs to be reprogrammed after each simple task is complete. If left unmonitored it will just kill you smoothly.

i was a Flight engineer in the US Navy... you really knocked it out of the park here with your description and so forth. nicely done

Going from automated to human-control-needed is one of the reasons why I think it will take soooo long for automated road vehicles to happen. If the driver needs to be VERY attentive only a small portion of the time, the driver likely won't be able to perform well enough all of a sudden.

Next video: tear down of a 737. 15% fibreglass reinforced?

Two Czechoslovakian brothers decide to move to America. They hop a boat and arrive at Ellis Island. The clerk calls the first brother and asks him what he does for a living. "I pilot!" "Ahh, that's excellent. We have a shortage of pilots in this country. Step right through those doors. Welcome to the United States." The second brother is called and the clerk asks him what he does for a living. "I chop-a da wood!" "Oh, I'm sorry, sir. We have enough lumberjacks already. You may not enter." "But why you let-a my brother in?" "Well, he's a pilot, a high-skill job." "Yeah, I chop-a da wood. He pile-it!"

Claims to not be a pilot; handles his stick like the best of them.

AvE and surround sound: Probably okay for a speaker. Not so good for headphones.

I'm a pilot. I tell all my nervous passengers there's nothing to worry about no matter what we're coming back down. And if they ask, "Where would you land if something happened right now?" I tell them not to worry.... I can land anywhere. ONCE.

phrase known in military flying. If its in the manual it was written in blood.

It was not on autopilot. MCAS is always on and moves the entire stabilizer NOT the elevator itself. 1. Boeing found 14% improvement in fuel by moving the engines forward and up 2. This made the plane unstable so they added MCAS to manage un-commanded nose pitch instead of re-working the aerodynamics to make the plane stable in all thrust situations 3. Boeing did not chose a better technology than a metal flipper to determine AOA at the nose 4. Making adjustments via the Horizontal Stabilizer is the "cheap" way to make attitude changes instead of a better integrated control over the elevator. Picture changing the direction of your car automatically by moving the rear wheels when you least expect it. So it is no surprise how this can really fuk up pilots not knowing this may happen.

Where is aves 737? Oh it’s torn apart

I flew airplanes for a living during the early 90's and have 7,000+ hrs experience flying B-737's to DC-8's and B-707's. There is a long way to go before the NTSB can determine the actual cause. Please do not focus solely on the Angle of Attack sensor. The leading suspect areas are sensor failure, decision process (Cockpit Resource Management) along with the information the sensors were sending to the screens. It's also important to note, the very reason the AoA sensor and MCAS (Maneuvering Characteristics Augmentation System ) are coupled is to prevent the aircraft from stalling when the autopilot is not on / armed, during any flight mode (climb, cruise or descent). This has been an area of concern because of another deadly problem in the past known as runaway trim. Runaway trim is caused when the electronic control system that controls aileron, rudder and elevator trim tabs has malfunctioned. Normally the trim tabs reduces the pilot control workload when manually flying the aircraft. When the autopilot is engaged, it could not be easily detected if the system failed during climbout after takeoff and could result in a climb stall or transition (turning autopilot off). Boeing's solution is MCAS. Investigators will have their hands full because of the complexity of the flight management system. It will be at least 12 to 18 months before all the facts are gathered and a full simulation can be accomplished. An interim report will likely be produced within the next 6 months IF the evidence is clear. But I doubt there is enough wreckage to support a quick investigation. There is no doubt a problem exists. Precisely what actual sequence of conditions sets off the problem is still unknown. For example, the manufacturing of the AoA will have to be investigated and thoroughly tested. The software and data interfaces will all require thorough testing. Pilot and Maintenance Engineering Training will require thorough review. This is particularly true of the first accident in Indonesia because the AoA sensor was replaced due to a technical fault, on a 7 month old airplane. These sensors normally last years. We do not have all the facts and any implications published here are premature. Have a nice flight.

When Boeing began developing the Max 8 in 2011, one thing was clear: The engine would be powered by a very fuel-efficient engine known as Leap, made by the company CFM. Boeing's rival, Airbus, had also equipped its well-selling A320neo with the same propulsion hardware. One of the reasons the Leap engine is so economical is because its air intake has an enormous diameter: 198 centimeters (6.5 feet). While the long-legged Airbus A320neo has plenty of room for such a massive engine, the landing gear on Boeing's Max 8 is short, limiting ground clearance under the wings. The engine simply doesn't fit. Pressed to come up with a solution, Boeing's star engineers came up with the idea of shortening the engine mount structure, which fastens the heavy engines to the underside of the wings. This did the trick, but it came at the cost of seriously altering the aircraft's flight mechanics. As a result, the Max 8 tended to dangerously raise its nose. Under certain circumstances -- rare and extreme, to be sure, yet possible nonetheless -- there was a greater chance of the plane stalling and even crashing. Boeing engineers, in turn, came up with another makeshift solution. They developed a software that would work in the background. As soon as the nose of the aircraft pointed upward too steeply, the system would automatically activate the tailplane and bring the aircraft back to a safe cruising plane. The pilots wouldn't even notice the software's intervention -- at least that was the idea. In fact, Boeing didn't even consider it necessary to inform pilots about the newfangled MCAS, or "Maneuvering Characteristics Augmentation System."

Never comment, but this why AVE is great on such topics - a considered perspective based on experience and open to the correction by those with more knowledge on the subject. If everyone took this approach to life, the world would be a better place.

Ah man, I'm 15 minutes late because I was watching Applied Science EDM drilling!!

Sweden doesn't have Harriers that I'm aware of. If it's any consolation there's a slightly less glamorous Cessna 172 that's festooned with a proper skookum AvE sticker here in Ohio.

Never met anyone who knows more about the mechanical than you, sure is a joy listening to you explain things.

The airplanes are flying too close to the ground. Dirt is too dense to fly in.

A friend and I were flying out of Philly many moons ago when the nose started to climb at a rate that was not sustainable. After a few minutes (felt like hours), of his trouble shooting (and myself shitting my pants), he discovered it was a trim failure with the auto pilot causing the plane to think it was descending. He really had to think on his feet to figure that out on the fly. It was only a small aircraft, but a crash hurts regardless of the size of a plane. If he reads this, thanks again bro.

Close (from 46 years of driving all over this ball, and an ex test pilot) Never trust the media to know truck all about aviation When the automation gives up, turn it off and fly the plane. If you can’t fly the plane without the automation with partial instruments, you should not sit in the front. I have flown with “experienced pilots” from third world countries that could not survive without the automation. This may not be case, but I thought I would mention it. Another is, when an aircraft type is new, the QRH/flight manual is thin. As schite happens, emergency procedures are developed and these manual get thicker over time.

Dude, I have no idea what this channel is about, but you are playing with power tools and I love your Canadian sense on humor! Subed

My best friend was on that flight, thanks for putting in some aspects of realization rather than being told what I want to hear. Still a good, honest, vidjeo

There are probably no flight engineers on that aircraft. I retired as a flight engineer, they're are few left now and usually fly older aircraft

Not even hand models have as much footage of their grubs as AvE.

I'm usually pretty fluent in profane canukish, but it took me a minute to decode "tungsten carbide".

"When in panic When in doubt, Yell in circles Scream and shout." You got a tee shirt with that?

A good way to understand LIFT is that it is a collaborative effort to keep Newton under the wing and Bernoulli above it.

On a side note, many airlines don't want their pilots to hand fly aircraft. As soon as the get airborne, the autopilot goes on, it doesn't get switched off until they are on finals to land, sometimes the autopilot does the landing too. This is meant to be a safety feature but the pilots are getting rusty at real flying. A bush pilot with 2000 hours in a plane with no autopilot can be far more experienced than an airline pilot with 5000 hours.

Listening to video with my hat on backwards. _casually turns hat round right wise_

"have you been with humans?...we're F'n morons!" and we have the un-erring ability to clone ourselves! See where this is going?

After 16 minutes of wondering how the hell that thing was going back in the shell I finally got my answer 😂

The most dangerous piece of equipment in a workshop is the untrained end user.

Excellent points about the idiocy of the talking heads. It’s almost like the stooges simply want to sell adverts to even more bigger idiots by over exaggerating, super sensationalizing and uuuuuugeeeely clinging to headline emboldening. Those are all things. Well, alas I’m happy to have your intelligent points to bring some comfort as I sit and ruminate on the meaning of flight-I mean lift. Dammit- life...also I think it’s fair to say that the comment section of your videos vastly exceeds the heights of even some of the loftiest channels. They bring the whole RU-vid world to a new height, a clearer horizon, jetting us onward and upward to the clouds of higher sinking- thinking. Dang it happened again, I’m done, all the breast. Best.

Ave it would be an honor to meet you someday i love this channel and the humor is priceless

The ideal flight crew is a pilot and a dog. The pilot’s job is to feed the dog, and the dog’s job is to bite the pilot if he touches anything.

At 7:45, you mention that there is laminar flow over the surface of a wing - just wanted to chime in and say that that's extremely false. The Reynolds number on a large jet is so high that the flow is immediately turbulent. Turbulence and flow separation are two different things. The flow is turbulent over the wing always, but excessive AoA causes separation.

Love this! You're pretty on point. And I've been to Whitehorse too, friend - I feel your pain. Cheers, from the high desert!

There’s these other RU-vid’s with these fancy graphics and animations and statistics, and yet I’ve just learned more then I have in any of those videos from this guy and his hand motions. 😁👍🏻 thank you for the video!

These rambling shop videos have always been my favorite!

quite off topic but i always find it wierd how the bernoulli-lift-explanation is etched into everybodys mind although it only accounts for a quite small fraction of the lift generated... in other words: how is it possible for a plane to fly upside down?

I like the way you edited out the mistake of putting motor on upside down. Lol

I gotta say these truly are a treat especialé, I’d like to think I learn something on each video I watch, big thanks from here in Ontario

this stereophonic experience sounds an awful lot like a bum headphone cable

I am sure the angle of attack sensors failure, compounded by pilot error due to lack of experience was blamed in a couple of crashes on different models over 10 years ago. In those cases they too fell out of the sky in a stall. The pilot issue seems to be getting more common as less and less ex-military pilots are flying passenger planes. There is no replacement or training methods to replace arse in seat time flying manually.

I was flying out of Vegas on a 900 Max a few months ago and felt that nose pitch you described right after take off. Seemed like it lasted about 10 seconds and then finally went back up.

Here's my research so far. The black box from the Lion plane that crashed said it had a malfunctioning anti stall (attack) sensor for the past 3 months. The plane had just came out of maintenance where multiple sensors had been replaced (but not the attack sensor). MCAS is used to prevent the plane from going into a stall and also smoothing out pilot commands and correcting pilot input for a smoother flight. Boeing has kept the exact same emergency procedure checklist so that pilots did not have to relearn anything new. If they had followed the check list (which has been the same for 60 years), 2 switches to manual trim would have turned off MCAS allowing pilots to manually control the aircraft. Also the black box from the Lion crash indicates the attack sensor had been faulty for 3 months and customers on previous flights had complained that their flights on that plane felt like a roller coaster. Also the pilots struggled 26 times to increase the angle of the plane without manually taking over the trim. Pilot and maintenance error 100% And SW airlines has a pretty good argument. "Southwest Airlines We remain confident in the Safety of our fleet of more than 750 Boeing aircraft. Southwest has operated approximately 31,000 flights utilizing the Boeing 737 MAX 8 aircraft, and we plan on operating those aircraft going forward"

Automate comes from the roots words "auto" meaning self and "mate" meaning to screw...

A few things: 9:40, to correct for the "runaway stabiliser trim" the pilot takes the 3 steps you measure one by one, if the first fails you move to the next. Normally just holding an opposing input on the trim button (the one on the control stick) is enough to stop trim from continuing to automatically move. The other two steps only are taken when the electrical input from the switch does not create the desired movement of the control surface, firstly disconnecting the electrical input to the trim system, and secondly manually adjusting (or holding) the trim wheel to get a desired input. 15:04, the Lion Air crash was very well covered in pilot circles, I would assume all pilots for the type were also given a reminder of the steps to be taken when one of these MCAS issues pops up. I would also not be surprised if there was another problem not related to the MCAS issue at all.

Best commentary on the incidents ever.

Do you think when the captain counts souls on board, they don't count gingers?

Spot on with your assessment. The most dangerous time for a ship (my area of expertise) or plane is arrival or departure. Sadly, this issue seems to be happening at one of the busiest and most stressful times (takeoff). I'm guessing that proper training and repetition can easily solve the problem, however, it seems a bit too late and should have been happening immediately after the first crash. As a ship captain (ships.....not boats ;) ), I can attest to the fact that we frequently have systems installed on our vessels in an attempt to make them safer. Often, these systems are designed by people with our best interests at heart, but in the end, they were made by people who don't truly understand the job. Frequently these systems need additional training, otherwise they become distractions rather than tools. In any case, I've logged hundreds of thousands of miles on 737's as a passenger and have the utmost confidence in Alaska Airlines pilots. (As I live in Alaska, they're kind of the only option unless I'm chartering to a remote village). I love your channel, keep up the great work!

Would it be possible to return to the previous audio arrangement/processing you had in former videos where the vocals are centered? In more recent videos the vocals have been off to one side (some more than others) for the most part which isn't as pleasant to listen to.

Nice job flipping the motor/trigger assembly back around the right way in the jump cut. Awesome vijeo by the way.

I wonder if the automatic braking systems on modern cars is going to lead us down a similar rabbit hole one day.

Put my computer on desk and plug cables back in after being away for the weekend. Start watching new AVE video. Spend 10min trying to figure out what's wrong with my stereo and why the left channel sounds quiet. Turns out to be the video. #facepalm

Good evening for New Zealand 🇳🇿 keep up the cool vids

So, just don't let the computer mess with her flaps. I can get behind that

Pilot here... your explanation is not teabag at all. Also, I hadn't considered the politicoeconomic side of the decisions and timing of grounding the planes in Europe vs the US; that's a good point right there.

Who else noticed he got the motor on upside-down before he did?

Awesome video to watch before travelling tomorrow

Not necessarily laminar flow. What you mean is an attached boundary layer. Stalls happen when the boundary layer on the top surface separates.

My cousin, Stéphanie Lacroix, was on Flight 302. Hearing some technical talk about the crash sure does help. Thanks AvE

If it's more than meets the eye, are the Decepticons finally attacking?

MCAS . Also a meat servo failure as well.

I love your videos. Your knowledge of electro mechanical engineering is quite enlightening. I hope I got that right. Anywho, your videos are quite entertaining and enlightening.

I enjoyed your video, thanks : )

Also, Bernoulli's principle makes wings more efficient, but it's not the main reason why wings fly, since there are plenty of airplanes with symmetrical wing cross sections. The main component of lift comes from the air hitting the underside of the wing, generating a high pressure zone, and the air above the wing having to turn to follow the contour of the wing in laminar flow. The kinetic energy of air molecules wants to pull the airflow away from the wing, creating a low pressure zone. So high pressure on the bottom, low pressure on the top, the wing moves up. What's more, the airflow at the trailing edge of the wing isn't horizontal or stationary. It's actually moving down. So the wing is taking stationary air and it's basically throwing it down. Equal and opposite forces.

I once boarded a UN flight from the heart of darkness to the middle of nowhere. As I’m walking out to the plane, the pilots are in front of me having a heated discussion. Now these two guys are looking a little rough and I can hear they’re speaking Russian or something like. Suddenly they both turn to me and ask me to help them settle an argument and ask what’s my favorite vodka. Well brother I tell you I was gripped at every little bump and was never happier to get off a flight.

Interesting way to deliver a message...well done.

Over reliance on technology can be detrimental to your wallet and health. You tear into new tools, checking for deficiencies, not relying on the manufacturer's assurances. A big reason why I subscribe to your channel.

Quick, get these planes full of takata airbags

1. 9:00 "It will tweak the nose down by adjusting the elevator" - The AOA/MCAS system uses the Horizontal Stabilizer Trim adjustment, not the Elevators. This is important because the Yoke controls the Elevators. The Elevators cannot overcome the trim, so grabbing the stick and pulling up is not sufficient. 2. 9:50 "He needs to do 3 things..." - First the pilot needs to turn off "Main Electric" in the "Stab Trim" group (It's actually in the picture at 10:09, there's two silver toggles in the far bottom left corner, it's the left switch). Second, that "ring" is the trim adjustment, when the problem happened it went furiously spinning to it's hard limit forward/down; that needs to be fixed. This is at the same time there are multiple warning about a variety of system failures blaring through the cabin. 3. 12:00 Conjecture: They were probably trying to fight the trim with the yoke/elevators, not understanding the problem. This likely explains the airspeed drop as well. At the end they probably tried to turn back, thinking they were essentially under control with the trim 100% fighting the elevators, but unable to control the turn, lost it. 4. 18:30 Boeing developed the training for the 737 MAX 8, and chose to skip mentioning the new AOA/MCAS feature completely. Similar Flight Envelope controller issues have cause half a dozen accidents in the last decade (particularly AirBus A320s). After the Lion Air accident Boeing released a bulletin, but still didn't update training. The 1505 page documentation does mention the MCAS feature. I can't fathom what they were thinking here, essentially burying the relevant information in the documentation.

Excellent video. You are closer to the truth than all the talking heads on all the news sources combined. Not just on the technical issue at hand but your insight into the state of the airline industry, on a global scale. I’m not surprised however. As a DIYer and all round curiosity seeker of all things mechanical, I’ve watched your videos with a mixture of awe at your breadth of technical knowledge, experience and skills as well as an enthusiast appreciation for your sense of humor. Very well done sir. Kevin Jones Delta Air Lines Pilot

Great stuff again. Cheers

I believe the spiny wheel thingy is the trim adjustment wheel or something

My theory: Boeing (and the FAA) overreacted to the Air France 447 Airbus crash in the South Atlantic in 2009 where pilots climbed into a stall due to bogus air speed readings. They applied a software fix to faulty piloting and created a new failure mode.

Great video, it sounds like I'm listening to my pops "Kid, planes are SERIOUS BUSINESS!" He worked as an A&P tech on Beech 1900's in the late 80's, early '90's. He also enjoys pointing out that, to his knowledge, FAA licenses never expire...

It funny in many ways 😂 the way you explain yourself and the pilots lol

MCAS(due to bad AOA sensor) may be the issue, but they had some pretty serious training 4 months ago. Hard to imagine that an issue that was thoroughly dealt with could again be the culprit. I'm not a pilot and I can tell them where the shut off switch is for the MCAS. Yeah, that guys razor, but those would have to be clueless pilots if it was MCAS.

Thank you for this.. just what my foggy, half asleep brain needed at 2:52am

Well said sir. And I wondered how long it was going to take you to realize you had put that together upside down.

I could listen to this all day

I would only fly aircraft like that if it was equipped with a "My Airplane!" button. One punch and I'm flying, not the computer. ...it's like participating in a CNC crash without an E STOP, except you are the cutting edge of the tool. No thanks...

I actually work in a Forge shop that manufactures the forging for a bunch of boing parts. Thankfully it’s just the landing gear so it’s not on my conscience.

My right ear is enjoying this video more than normal.

I would appreciate your learned council regarding the coming 5G Roll out. Thank you for what brings you joy

Too often people die due to an over reliance in automation. If in doubt disconnect the autopilot and fly the plane. Let the co-pilot figure out what's wrong while the pilot flies the plane.

Btw your explanation on how wings (more specifically, airfoils) work is erroneous, however your description of what causes an aerodynamic stall is basically correct. Mind you, this has nothing to do with the point of the video, but I thought I'd point it out for your own knowledge. I'll put links with accurate descriptions below once I finish watching.

Boeing had put out a memorandum regarding this problem and what to do if it happens. As to whether this got to all the pilots in 3rd world locations is up to debate. A memorandum is a weak way to communicate. I've been a passenger on a lot of flites including a good many 3rd world airlines. I've flown off an aircraft carrier and piloted light planes. When things go astray the pilot needs to have enough training to automatically take the necessary actions, immediately. I don't think a memorandum represents that level of training.

MCAS should stand for "Might Crash Airplane Suddenly."