Mentor Pilot proves a very good point. On the Ethiopian crash, they apparently re-engaged the stab trim back on four times to try and regain control the trim as it was impossible to change the trim manually as shown in his video with the high speed. I wonder how many 737 pilots are trained to perform the rollercoaster manoeuvre to move the trim manually with disengaged stab trim?
Kevin Taylor I believe the roller coaster maneuver was out of question for the Ethiopian as the out of trim stabilizers had already overwhelmed the elevators. So pulling on the yoke was futile. Also they were too close to the ground, and did not have the luxury of altitude to perform such maneuver.
I know this might sound crazy, but if you can’t trim because of aerodynamic forces, get some passengers to move temporarily. In the scenario demonstrated, have 8 to 10 passengers in the front row go to the rear galley. That will move one ton from the front to the back. Obviously this is dangerous for the passengers, but it’s better than losing control of the aircraft and crashing. The roller coaster makes sense, but if your altitude is too low, then you can’t do it. The only option left is to move the CG, to unload the stabilizer. If you need to add nose down trim, just invite any pilots to visit the cockpit and I’ll be there in a jiffy. The passengers will just think it’s professional courtesy, but I’ll know you need help (because FAA regulations prohibit passengers in the cockpit) and you are deviating to save the flight.
Seeing you guys struggling to trim the aircraft brings chills really, only God knows what struggles the crews of Lion Air and Ethiopian Airlines went through
This video is not related to the MAX it shows a feature which is well publicized in manuals and should be fully understood by people flying the aircraft.
I totally understand that it has nothing to do with the max accidents but still it brings chills, knowing what the problem is and knowing how to fix it yet you can't because of aerodynamic pressures, very chilling
What's the red button you mentioned? Can you do a tour of the behind the scenes parts of the flight simulator machine? I think that would be fascinating.
I heard in a video somewhere, at some point, that it's bad luck to let the simulator crash. I presume the red button is a stop button. If you are certain the plane is going down, there is no point in letting it play out, and hence, bad luck.
Mentour Pilot, I have been made aware that the excessive force required to manually trim the horizontal stabilizer on the B737 goes way back to the first airplanes and at one time Boeing had a flight manual procedure on how crews were to deal with it. So why didn't the FAA demand that Boeing redesign the system to correct the problem? Was it because up until the Max8 debacle it was simply a non issue because the main electric trim system never failed to operate and never ran away and the autopilot servo motor was almost as good? In 32 years working on 737's I only saw one autopilot servo motor that failed to operate and that was because a human removed it's electrical connector before flight and failed to reinstall it. Therefore the crew simply didn't use the manual trim because it was not need until the Max8 debacle which forced the crew into trying to use a system that Boeing and the FAA knew would not work under the conditions that the crew was faced with. In my opinion a chain failures led up to this situation and they are as follows: #1 AOA sensor provides false data to poorly programmed MCAS system #2 MCAS causes autopilot stab trim to run toward full nose down trim. #3 Flight crew treats this as a runaway trim situation and follows the flight manual. #4 flight manual says turn both stab trim cutout switches off and left off. #5 Boeing has changed the wiring on Max8 airplanes so that turning off either switch turns off both motors and also tuning on either switch back on turns on both the defective autopilot servo motor and the good main trim motor. #6 Crew is forced to turn the cut off switches off again and trim the stabilizer manually, which they cannot accomplish and we all know the sad ending.
Between the advice of "not try this at home" and Patxi's teleportation super power I am speechless..!! Hahah great video as allways, thankyou Peter for this kind of demonstrations, showing the case of something going beyond all limits.
I love your Channel and all the information and lessons that you teach me. But I have to say that you're dog is so cute. I always watch it in the background. He/she really loves you!!
21:07 Dan Air 1008 had this situation, when the pilots tried to do climb over terrain, but they banked more than 35°. They just reduced the sinkrate although they gave full thrust and the nose up
There are ATC video's where the traffic control was telling the pilot to turn x direction to y heading. IE: Turn Right heading 270. For some reason the pilot turned the other direction. (left) ATC tried twice to get them to turn the right direction. After the 2nd time they were close to terrain and she was warning them about terrain and immediate execute clime to 15000 ft. Then the pilot decided to turn and went into the mountain.
Mentour, I'm a bit confused by the opening video that seems to show the FO attempting to crank in nose down trim with little effect. Why nose down? When you get to the actual sim sequence, he seems to be properly cranking the trim nose up also with great difficulty, but at least in the proper direction. Is this an out of sequence bit of editing? Regardless, it's confusing. As always, an absolutely fantastic video!
Tom ... Same reason he doesn't mention ignoring the runaway trim procedure by apparently leaving the AutoThrottle on or by moving the Stab Trim CUTOUTS back to Normal, etc., etc. ... So many questions, so little time. _
This is where Boeing and FAA made a grave mistake. MCAS is kind of like an auto-pilot system that has authority to trim the aircraft without asking or telling the pilots (other than the noise and seeing the trim wheels spooling). This is so new to the industry. When flying on autopilot, the robot flying the plane does a very nice job of doing so. Also, while the robot is flying the plane, as need arises, it will run the trim in nose up or nose down, depending on what the autopilot needs to reduce the trim forces that it is sensing. Pilots are used to seeing this happening while on autopilot, NOT while autopilot is off! If the human pilot does anything to intervene with the robot’s use of the pitch trim, the robot (autopilot) will sound off a warning bell and then pilot (human) will have to hand fly the plane and trim as needed. It’s been that way for decades. If you just barely touch either one of the power trim switches located on the control yokes while autopilot is flying then boom! Off goes the autopilot, The autopilot off warning bell sounds off, and the flying of the plane and FULL AUTHORITY of the trim system is given to the pilots. In other words, the autopilot doesn’t want you messing with the trim while it is flying the plane. It has to be able to trim the control forces away as needed otherwise it cannot do it’s job properly. In the past, the planes were designed so that when the autopilot is switched off, the ONLY way for trim settings to be changed was by a pilot calling for it or if there was a majorly bad malfunction like a runway trim situation which is very rare but pilots are all trained for it. What Boeing has done on these new 737 Max is that they’ve made running of trim with with autopilot off (without pilot intervention) go from a very remotely rare event to a new commonplace in the cockpit. Used to be that if you were hand flying (autopilot off) and the trim started running all by itself, you needed to very quickly get it stopped! If you failed to stop it you would find yourself in a VERY bad situation VERY quickly! Now Boeing has decided to change that all around and make (MCAS) motoring of the pitch trim (without pilot intervention) commonplace in the cockpit with STILL the threat of it running too long (runaway trim) and causing a nosedive with resultant smoking hole in ground. And all I’m hearing from Boeing is that this MCAS thing is not needed as a safety device or an implement to make an unsafe and unstable airplane safe and flyable, NO, it was only added so that this new plane with bigger engines would fly and feel so much like the earlier versions (B-737) that any pilot with a 737 type rating could fly it without $$$ EXPENSIVE $$$ special training which would be bad as it would hurt the shareholders and might cause the consumer ticket prices to go up. Rather than trying to update the software, blah blah blah ...... if the MCAS truly is only needed to make the plane feel and fly just like the earlier 737’s (like Boeing is claiming) then just remove the dumb thing (MCAS) and chalk it up as a very bad idea that cost two very bad accidents in less than 6 months and then spend the money and time and retrain the pilots so they will know that this new plane is very conventional and safe but it flys a little different than earlier versions. We have way too many acronyms already without having to learn about MCAS. (Maximal Casket Allotting System)
wow good demonstration, are people not shocked that this also happens on a boeing NG? maybe a motor with siwtches up/down to control the trim manually?
the trim wheels being hard and slow, the manual procedure seems applicable in only few cases for small trim adjustements. As demonstrated in simulator, others "run away" cases when plane level is too far out of trim... very limited chance of success. 😂
@@VladimirNicolici Ah. Well, regardless, it seems obvious that the procedures should have the crew trim to neutral stick before killing the electrics if the stabiliser still responds to the toggle on the yoke. From my understanding they don't - and still don't (didn't) in the Max. It also seems inherently dangerous to design a plane where the trimmed control surface cannot be aerodynamically overcome by movement of the elevator/yoke - particularly if it is also impossible to manually trim because the manual backup system lacks the mechanical advantage to do so in extreme circumstances. I realise that direct mechanical control connections are one of the advantages of the 737, but it does seem now that they are less than sufficiently robust to handle the plane in a number of foreseeable scenarios. It's a beautiful little plane - but it's a flying can of hacks and compromises which seem finally to have consumed whatever safety margins were initially built into the design. I think the Max should have been re-certified in the first place, not grandfathered in.
@Thomas Headley ... Why would the overheads be opened? Doesn't make sense for the maneuver shown. It's not a rapid, violent drop like would happen in strong turbulence.
Thanks once again: I was looking for that video covering "terrain escape maneuver ", I was watching at the end but saw only a call to bank. what did I miss ?
The trim wheel should have a hydraulic system (with multiple redundancies) so that you can move it while the motor is shut off without applying insane amounts of physical force.
I have a question: at the end of the mis-trim demonstration, you said "Juan, press the red button. Press the red button now!" I assume that aborts the simulation. There seemed to be some urgency in your voice. What would have happened if you had carried on? Is it possible to damage the flight simulator or would it just have become quite unpleasant inside it?
I'm no pilot, but I am an industrial mechanic. Quick question: Assuming you had the altitude could you not momentarily... Nevermind. I should have watched the whole video before commenting.
If the airplane is at sufficient altitude, would it make sense to roll the plane 90 degrees to essentially turn the elevators into rudder? That way, pilots may be able to unload the elevators and trim.
Not 90 degrees because large passanger jets are certified up to bank agle of max 60 degrees. But theoretically yes, if you have enough altitude to play with, significant bank will make manual trim easier.
You have to remember that Boeing had intelligent management in 1967. And the employees were totally dedicated to the company. That is no longer the case. Profit and greed is the new case. The Max is a prime example and in conjunction with a mismanaged FAA, the new receipe is disaster no matter what the cost or who it hurts.
I wonder how this works on the Airbus, an A320 for instance. I assume there is no possibility to trim the stabilizer manually using the physical connection?
I wish they had a separate motor to run the stabilizer trim for redundancy. How about fly by wire technology that the Airbus uses? Is the Airbus more advanced and should the Boeing max be seriously updated?
I would like to know the exact force needed to trim the stabilizer like this. I would love to know how hard it actually is. When u lose power steering in your car it can be incapacitating to women or to men who are not physically strong. But a strong, blue collar man will just find it annoying...
Thank you so much Mentour for such an amazing, informative and comprehensive content.. I have a suggestion; what do you think of creating a special website to explain the basics of flying for beginners and freshmen in Aviation Schools? It would be much appreciated.. Your way of explaining is so appealing and i can guarantee the success of this project
Mentour Pilot It would facilitate the studying and would improve our basic knowledge of aviation and also would prepare many students to their aviation school life and strengthen their knowledge
Is anyone else thinking, why are the stab trim wheels so small? It seems manual trim is almost impossible, especially in an emergency situation ala 737 MAX runaway stab.
It's impressive. Hard to include the awful sense of jeopardy of a real crisis, though. The screams from the passengers, the panic, the knowledge that if things go badly wrong you WILL die. No reset button. I suppose that's why they pay test pilots so much.
The part I don't understand is why there is no disengage that stops all automatic trim inputs (ex. MCAS) but allows the pilot using the electric motor to trim manually. Car analogy: I touch the brake or shift gears, the cruise control disengages. I can then accelerate, brake and turn manually. The cruise control does not re-engage again. This system as it was built is like a car designed so cruise control can only be disengaged by turning off the engine, losing brake assist and power steering as well.
Great analogy! Spot ON! Only explanation that makes any sense to me is that Boeing ran out of money after paying their CEO & management & shareholders.
I can see that it is almost impossible to trim any 737 manually further nose-down if the mis-trim is already down. But the BAD situation is that it is IMPOSSIBLE to trim it manually in the REQUIRED direction to save the aircraft, to trim it nose-up. The cranking of ONE pilot can NOT overcome the aerodynamic force that is against the manual trim-up effort. Two pilots would be needed to overcome the limitations of the mechanical (emergency) system. But one of the pilots has to pull the yoke back with all his force and has no free hand to assist the manual trim effort at his side with the second cranking handle. The FAA should look into this too. Why was the 737 NG certified in this DEFICIENT way? The problem was already existing before the 737MAX. Suggestion: The TRIM CUTOUT switches should be changeover switches that disconnect the primary electric trim system that includes the autopilot trim, trim switches at the pilot's control wheel and the electric motor near the jackscrew. When doing the switchover there should be an alternate electric trim system with an alternate (additional) set of trim stitches at the control wheels and a DC-motor in the pedestal which (via a clutch) is able to drive the trim-wheel in the pedestal. The electric DC motor has to have enough torque to drive the (former exclusively manual) system and should be connected to the Emergency DC bus. Second suggestion: FAA should mandate this modification to ALL 737 within six months.
Would it make sense in a situation like this to triple-gong the purser so he can work on the captain's side handle of the trimwheel while the captain handles to control column?
You may have to land a plane one day. Its always good to know & not need it than to need it & not know it. In the unlikely event that this happens youll thank your lucky stars & save your life.
Speculation vindicated!!! Speculation is a good thing. We humans and most other creatures have intelligence thanks to intuition which is another word for subconscious speculation that we use when we don't have all the facts. In this video, we have an honest demonstration of a troubling scenario, presented without name nor blame, and not claimed to be any historical fact. It does, however, calibrate our intuition about what may have happened, or can happen in the future. Thank you so much for showing us the "devil in the details" that is so decisive when things do go terribly wrong. Thank you for getting us intellectually involved in discussing and understanding what ultimately matters in the outcome.
That was an Absolutely Fantastic Video!! Great explanation at the end of why you shouldn't turn to avoid terrain if you don't have visual! Great Stuff!!
EveryTypeOfVideo - Hi! Yes, you're right. Instrument training is bizarre. The cockpit's blacked out completely, so you can see absolutely nothing but your instruments. Learning to rely exclusively on them when you have (literally) zero visibility is enormously difficult and utterly non-intuitive. It feels totally unnatural. Your senses are screaming at you that you're banking, or diving, or climbing, or even completely upside-down, but you have to ignore the urge to try to make sense of things. It's very hard to trust instruments alone when flying blind, but it's even harder to reject what your body's telling you to do. When up feels like down and left is 'obviously' right, you have no hope of avoiding disaster without the right training.
Mentour, GREAT VID! I can't help but to wonder what happens to a pilot after a missjudgement like in your "terrain, terrain, pull up" video? Does the pilot file a report and if so what then? Thanks.
Mentour Pilot, I would like to thank you for addressing the question about terrain escape maneuver and for providing further explanation in this subject. You are doing an absolutely fantastic job with those videos. Keep it going and have a lovely, clear sky.
The MCAS glitch caused it to take over the horizontal stab and put the plane into a dive. The pilots corrected by switching off the toggle switches to disable the automatic horiz stab control. Question I still have: Why did the pilots switch the toggles back on? Was it because, with the toggle switches off, the hand crank is also disabled, and so they had no choice but to switch the toggles back on to have a chance of recovering from the dive? Even without the horiz trim way out, why would it be so physically strenuous to manual trim using the hand cranks? There's no motor assist for the hand cranks? It's just old fashioned mechanical linkage?
The mechanical backup system is connected to the trim actuators by cables and drums. MCAS had driven the system to the stops using the electric motors and no amount of manual force could overcome the aerodynamic forces at the speed, altitude and elevator positions existing.
@@paulavery366 Part of the problem on the Ethiopian airplane is that the crew never did anything to control their speed, when the aircraft pitched down. They basically went into the dirt at takeoff power. They also didn't cut out the trim system until the aircraft was badly mistrimmed. As a result, the airplane was flying at or beyond its maximum operating speed, and the pilots could not overcome the aerodynamic forces with the manual trim wheels. They likely turned the trim system back on because they believed that only the motors could budge the stabilizer.....which was true, but they would have needed to do things perfectly to recover. They were likely almost beyond the point of no return. Their only real hope of recovery would have been to get the power to idle, pop the speed brakes, turn the trim system back on and IMMEDIATELY dial in some nose-up trim, followed IMMEDIATELY by again turning off the Cut-Out Switches. If they could get the airplane slowed down and get the stabilizer far enough off the full nose-down position, they might have had a chance to manually trim the airplane......or perhaps go another cycle of turning the trim back on, dialing in a burst of nose-up trim, then turning it back off again.
+Good lord, this is a major screw-up in design. This has happened because of newbie designers and engineers and lack of learning from previous generations .
This is confusing: isn’t the copilot trimming the wrong way?? The pilot wants to go up and the copilot seems to be trimming the nose down! Also, is the roller coaster maneuver even possible? It does not seem to be possible to pull up in order to later let go. Would reducing speed be better? Would some flaps help?
Yes, the copilot attempt to replicate a full nose down trim runaway. After he fails to bring it full nose down he attempts to reverse it and trim correctly at the end. That's even harder, simulation ends.
I'm really mind-blown. I don't understand why in a big plane like a 737, a pilot should ever be required to use a big amount of his physical strength on the controls in order to move the elevators, or any other flight control surfaces for that matter. An electrical engine that weights about 4kg is able to match and exceed any amount of force that a person can exert with his arms. Surely we should have the technology to do that on such a big plane! Having to struggle with any demanding physical task seems very distracting, and an impairment for pilots that could already find themselves in a high-adrenaline emergency situation. And considering that male pilots already seem to struggle, female pilots could have even more of a hard time coping with that. I can understand that the need to apply more pressure on the control stick can provide some useful feedback information to the pilot, but surely it should be possible to employ some servo-assisting technologies similar to the ones employed in modern car steering wheels, so that the pilot could still feel some pressure on the control, yet they would never have to struggle to push or pull the controls.
He's demonstrating extreme control forces created by intentionally extreme mis trimming of the horizontal stabilizer. Pilots would not do this intentionally on a real flight. Perhaps test pilots in certification flight tests.
Video is 20 minutes long, published 10 minutes ago and yet people are saying nice video etc etc, am I the only person who actually watches this full video?
Looks to me like the method of applying force to the trim wheels could be designed better, something that gives the pilots more leverage. Seems very clunky, and in an emergency situation could be downright dangerous.
Um... Fair enough idea in theory when everything's nice and calm and measured and logical, but impossible to arrange on a real flight with panicked, screaming passengers, struggling pilots, and a plane plunging towards destruction. Calling a suitably competent passenger to the cockpit isn't really the same thing as declaring a medical emergency and asking if there's a doctor on board. I think your idea would be the kind of suspiciously convenient Arnold Schwarzenegger 'magic wand' solution you'd find in a big budget Hollywood disaster film. ;-)
Very interesting. Stressing the incredibly wide speed range of a big passenger jet is vital information for a lot of people who perhaps aren't familiar with aviation. A small plane like a Piper Cub or a Cessna 172 will have a takeoff and landing speed not much different from its cruising speed. So, say, from 75mph up to 140mph (NOT accurate figures, just an example!). A big jet might cruise at over 500mph, but take off and land at only 130 or so. That's a huge difference. Imagine driving a car without power steering at its top speed of 120mph. Then try it at 240mph. Then 360mph. Then 480mph. The steering forces would be incredible, and very difficult to control. Air is amazingly thick, dense, 'heavy' stuff at high speeds. It's more like pushing against water, so it's easy to imagine how hard it must be to overcome a big jet's colossal aerodynamic loads without hydraulic assistance or any kind of 'power steering'.
Not sure what your point is. In the video the elevator control still has hydraulic power assist, which was working well. Power assist always has a taper-off function where there is decreasing assist towards the limit of the movement as well as a reduction of assist with increasing speed. This is to prevent slamming the controls against their mechanical stops with destructive force and to avoid abrupt maneuvering loads that could exceed the strength of the structure or could cause violent maneuvers that jeopardize the mission, e.g. cause a rollover in a car or skidding and loss of traction. The whole point of trimming is to position the stabilizer so it is doing all the work to hold the airplane in the desired pitch attitude with zero force on the elevator, i.e. for a 737 and other large airplanes, the elevator is in its neutral position, lined up with the stabilizer's chord line, with deflection from that position available to cause quick changes in pitch attitude if necessary.
I was wanting to go to toilet after a big meal and there was a Long queue once, Unfortunately No matter how Hard tried i couldnt apply enough back pressure. I Had to Dump Fuel There and Then !!
That reminds me of a story in my initial pilot training when I was flying a small Cessna cross country (by myself). On those long flights and not having a toilet, I had to use an empty bottle to dump my fluid into. When I lifted the now filled bottle and reached behind to put it back into the cargo area, I had to re-trim the aircraft afterwards. I was surprised that it made a small but noticeable difference.
I do wonder why there's no possibility to disengage all systems that automatically trim the aircraft without also disengaging the manual trim using the motor. I can see how being able to physically trim the aircraft is valuable if the motor breaks or can't be controlled anymore but there should be a step in between where only the automatic stabilizer systems are disengaged in my very humble opinion. Can anyone shed any light on this design decision?
Spot ON! You nailed it! There should be a new step in between where ALL auto control systems are disengaged but the jackscrew electric motor remains in play controlled by the cockpit up & down trim pushbuttons.
Terminologydoes vary according to application so this is aan observation from my engineering field. I would call a jack-screw as a treaded bar rotating in a simple nut (possibly with a swiveling yoke). Aero applications in my terminology convert rotary to linear motion with a ball-screw instead of a nut. Less friction, less wear and much smoother motion.
Not all aero applications. The reduction in friction and wear that a ball screw has also comes with a greatly increased number of moving parts and paradoxically, decreased reliability, and some aero applications don't need any of that.
Maybe Boeing should add a two speed wheel control (like boat's winches) in case of high speed manual trim operation) Or require mandatory workout for first officer ;)
there is a trim wheel on each side. Seems the nature of manual trim wheels make them useful in only a few situations (slow operation, lower air speed, surface load). Adding a few intermediate gears could make the trim handles EFFORTLESS, right ??
@@glasser2819 With the right gearing, a hex "nut" on the wheel axle, and a handful of charged up Harbor Freight cordless drills (better buy their "premium" brand to pass FAA muster) with matching sockets on them in the cockpit, that should work fine.
Seems like a second set of electric trim motors not linked to the automation would of been better than a hand crank. Like they say in the GTA 5 avenger mission "who still cranks?"
Q: At the start if the sim you must have been over-trimmed too much nose down, so you applied backward force on the yoke to nose up. Why then was the copilot trying to increase more nose down trim by moving the trim wheel forwards? Should he not have been pulling it backwards to trim nose up?
Mentour Pilot, or anyone who knows, can you explain the EXACT difference in function of the 2 Stab Trim Cutout switches on the various 737 models? A thread / comment on a machinist forum claims the 737NG has the switches labeled as "Stab Trim Cutout" & "Auto Pilot Cutout" meaning that the Stab Trim Cutout switch deactivates ALL power to electric trim motor but the Auto Pilot Cutout disables ONLY automated trim commands leaving the pilots thumb trim switches functional. So the function of the 2 switches is DIFFERENT. As I understand it--- in the 737 MAX what used to be the "Auto Pilot Cutout" switch is simply labeled as a "Backup" for the "stab trim cutout", both switches have the SAME function and are always operated together. I looked at google images of 737 stab trim cutout switches and indeed I see switches labeled both ways but the pics are not necessarily noted as to which plane version they belong to. In all the discussions about those cutout switches and runaway trim I've not heard any case where one switch would be operated without the other, they are ALWAYS moved together. Many comments on the recent 737 MAX crashes have suggested there needs to be a way to shut off the automated trim commands but leave the manual electric trim functional. Some even suggesting there needs to be a BIG RED BUTTON to deactivate uncommanded trim inputs. Can it be that earlier 737 versions indeed have this ability? But the MAX does not?
NOTE: couch pilot the stab trim cutout probably cuts out the switches on the yokes and the autopilot one the autopilot. they're probably always moved together because the pilots are not isolating the fault yet. The "big red button" is probably the AP disconnect switch on the yoke switch is used to quickly cut power to the trim motor. (easer to push) I'm not sure about the differences between earlier 747s and the 747 MAX (again, couch pilot) but I'm pretty sure that's it.
@Scott Mayfield Hey master troll who is talking about crashes? Things is that no matter what the situation is you are still going to be able to trim up/down using 1 finger not fighting for dear life. And is not this the point of flying... Controlling the aircraft, not persuading it and begging it ?
Flight Attendant comes on the PA and asks: Can anyone fly a plane? Someone replies: Yes! FA: What kind of experience do you have? Person: I watched Mentour Pilot videos! FA: ...........
Thanks for great videos. I would have enjoyed you getting out of the mis-trim as if it were real and also telling us about the altitude loss as it was going on.
i believe the newer fly by wire joystick is the oposite of the older fly by cable with a yoke control. Airbus did away with the weight of some mechanicals and replaced them by mostly reliable software logic
Reminds me of the time I took off from Palm Springs in a Cessna 172. There's a mountain on runway heading, which I had been told to maintain, and I felt like departure had forgotten about me, as I got closer to it. I finally asked, "can I turn?", and they said, "Yes, assume own navigation". I turned!
"do not do this at home". what a nice hint for us guys flying around in a 737 at home :D
Die Besoffenen Straßenköter Gedenkkanal Exactly what I was going to comment
We are so lucky that he warned us.
Armchair pilots.
It's actually perfectly safe to perform this as shown in the video - no simulator was harmed in the making of the video.
i did try this at home before he warned me - will I be OK?
"Control collumn: Hold firmly."
"OOOOOOH I am."
Had me busting laughing.
Mentor Pilot proves a very good point. On the Ethiopian crash, they apparently re-engaged the stab trim back on four times to try and regain control the trim as it was impossible to change the trim manually as shown in his video with the high speed. I wonder how many 737 pilots are trained to perform the rollercoaster manoeuvre to move the trim manually with disengaged stab trim?
Kevin Taylor I believe the roller coaster maneuver was out of question for the Ethiopian as the out of trim stabilizers had already overwhelmed the elevators. So pulling on the yoke was futile. Also they were too close to the ground, and did not have the luxury of altitude to perform such maneuver.
@@eudofia how is Boeing getting away with such an oversight!?
@@DanA-ji1vm Beats me. I guess they are too big to fail, and so are getting away with everything.
I know this might sound crazy, but if you can’t trim because of aerodynamic forces, get some passengers to move temporarily.
In the scenario demonstrated, have 8 to 10 passengers in the front row go to the rear galley. That will move one ton from the front to the back.
Obviously this is dangerous for the passengers, but it’s better than losing control of the aircraft and crashing. The roller coaster makes sense, but if your altitude is too low, then you can’t do it. The only option left is to move the CG, to unload the stabilizer.
If you need to add nose down trim, just invite any pilots to visit the cockpit and I’ll be there in a jiffy. The passengers will just think it’s professional courtesy, but I’ll know you need help (because FAA regulations prohibit passengers in the cockpit) and you are deviating to save the flight.
I have myself been on a flight where passengers have been asked to move to help trim the plane.
Seeing you guys struggling to trim the aircraft brings chills really, only God knows what struggles the crews of Lion Air and Ethiopian Airlines went through
I am sure the folks at Boeing hate this video.
This video is not related to the MAX it shows a feature which is well publicized in manuals and should be fully understood by people flying the aircraft.
I totally understand that it has nothing to do with the max accidents but still it brings chills, knowing what the problem is and knowing how to fix it yet you can't because of aerodynamic pressures, very chilling
@@MentourPilot Dude, you were hugging the yoke, the force should have been huge...
Very good video, though!
What's the red button you mentioned? Can you do a tour of the behind the scenes parts of the flight simulator machine? I think that would be fascinating.
Q: What's the red button you mentioned? A: self destruct.
I think it's the record button on the camera.
i much believe it has to do with the motion of the simulator platform. an emergency stop switch to the platform..
@@altavaer oh yeah that makes sense.
I heard in a video somewhere, at some point, that it's bad luck to let the simulator crash. I presume the red button is a stop button. If you are certain the plane is going down, there is no point in letting it play out, and hence, bad luck.
Mentour Pilot, I have been made aware
that the excessive force required to manually trim the horizontal
stabilizer on the B737 goes way back to the first airplanes and at
one time Boeing had a flight manual procedure on how crews were to
deal with it. So why didn't the FAA demand that Boeing redesign the
system to correct the problem? Was it because up until the Max8
debacle it was simply a non issue because the main electric trim
system never failed to operate and never ran away and the autopilot
servo motor was almost as good? In 32 years working on 737's I only
saw one autopilot servo motor that failed to operate and that was
because a human removed it's electrical connector before flight and
failed to reinstall it. Therefore the crew simply didn't use the
manual trim because it was not need until the Max8 debacle which
forced the crew into trying to use a system that Boeing and the FAA
knew would not work under the conditions that the crew was faced
with. In my opinion a chain failures led up to this situation and
they are as follows: #1 AOA sensor provides false data to poorly
programmed MCAS system #2 MCAS causes autopilot stab trim to run
toward full nose down trim. #3 Flight crew treats this as a runaway
trim situation and follows the flight manual. #4 flight manual says
turn both stab trim cutout switches off and left
off. #5 Boeing has changed the wiring on Max8 airplanes so that
turning off either switch turns off both motors and also tuning on
either switch back on turns on both the defective autopilot servo
motor and the good main trim motor. #6 Crew is forced to turn the cut
off switches off again and trim the stabilizer manually, which they
cannot accomplish and we all know the sad ending.
Between the advice of "not try this at home" and Patxi's teleportation super power I am speechless..!! Hahah great video as allways, thankyou Peter for this kind of demonstrations, showing the case of something going beyond all limits.
You went ahead with the “Red” and “Green” (port and starboard) pillows! Yay
This has to be one of the best channels of UA-cam , if not THE best! Thank you!
I love your Channel and all the information and lessons that you teach me. But I have to say that you're dog is so cute. I always watch it in the background. He/she really loves you!!
"Do not try this at home" mmmm that made me feel special 😂😂😂
Hahaha Patchi just teleported in :) I have a question though, is the 'Red Button' to end the simulation? You mentioned a red button at the end.
21:07 Dan Air 1008 had this situation, when the pilots tried to do climb over terrain, but they banked more than 35°. They just reduced the sinkrate although they gave full thrust and the nose up
It is very impressive showing your pilot`s skills and what could happen behind the scenes - but I am thinking about using a train next time.
There are ATC video's where the traffic control was telling the pilot to turn x direction to y heading. IE: Turn Right heading 270. For some reason the pilot turned the other direction. (left) ATC tried twice to get them to turn the right direction. After the 2nd time they were close to terrain and she was warning them about terrain and immediate execute clime to 15000 ft. Then the pilot decided to turn and went into the mountain.
Mentour, I'm a bit confused by the opening video that seems to show the FO attempting to crank in nose down trim with little effect. Why nose down? When you get to the actual sim sequence, he seems to be properly cranking the trim nose up also with great difficulty, but at least in the proper direction. Is this an out of sequence bit of editing? Regardless, it's confusing. As always, an absolutely fantastic video!
Tom ... Same reason he doesn't mention ignoring the runaway trim procedure by apparently leaving the AutoThrottle on or by moving the Stab Trim CUTOUTS back to Normal, etc., etc. ... So many questions, so little time.
_
They attempted to make the trim worse first before attempting to correct it, to show how it would behave when the mistrim is almost full nose down.
4:33 near miss collision with Mentour Pilot's elbow and his dog
This is where Boeing and FAA made a grave mistake. MCAS is kind of like an auto-pilot system that has authority to trim the aircraft without asking or telling the pilots (other than the noise and seeing the trim wheels spooling). This is so new to the industry.
When flying on autopilot, the robot flying the plane does a very nice job of doing so. Also, while the robot is flying the plane, as need arises, it will run the trim in nose up or nose down, depending on what the autopilot needs to reduce the trim forces that it is sensing. Pilots are used to seeing this happening while on autopilot, NOT while autopilot is off! If the human pilot does anything to intervene with the robot’s use of the pitch trim, the robot (autopilot) will sound off a warning bell and then pilot (human) will have to hand fly the plane and trim as needed. It’s been that way for decades. If you just barely touch either one of the power trim switches located on the control yokes while autopilot is flying then boom! Off goes the autopilot, The autopilot off warning bell sounds off, and the flying of the plane and FULL AUTHORITY of the trim system is given to the pilots. In other words, the autopilot doesn’t want you messing with the trim while it is flying the plane. It has to be able to trim the control forces away as needed otherwise it cannot do it’s job properly. In the past, the planes were designed so that when the autopilot is switched off, the ONLY way for trim settings to be changed was by a pilot calling for it or if there was a majorly bad malfunction like a runway trim situation which is very rare but pilots are all trained for it. What Boeing has done on these new 737 Max is that they’ve made running of trim with with autopilot off (without pilot intervention) go from a very remotely rare event to a new commonplace in the cockpit. Used to be that if you were hand flying (autopilot off) and the trim started running all by itself, you needed to very quickly get it stopped! If you failed to stop it you would find yourself in a VERY bad situation VERY quickly! Now Boeing has decided to change that all around and make (MCAS) motoring of the pitch trim (without pilot intervention) commonplace in the cockpit with STILL the threat of it running too long (runaway trim) and causing a nosedive with resultant smoking hole in ground. And all I’m hearing from Boeing is that this MCAS thing is not needed as a safety device or an implement to make an unsafe and unstable airplane safe and flyable, NO, it was only added so that this new plane with bigger engines would fly and feel so much like the earlier versions (B-737) that any pilot with a 737 type rating could fly it without $$$ EXPENSIVE $$$ special training which would be bad as it would hurt the shareholders and might cause the consumer ticket prices to go up.
Rather than trying to update the software, blah blah blah ...... if the MCAS truly is only needed to make the plane feel and fly just like the earlier 737’s (like Boeing is claiming) then just remove the dumb thing (MCAS) and chalk it up as a very bad idea that cost two very bad accidents in less than 6 months and then spend the money and time and retrain the pilots so they will know that this new plane is very conventional and safe but it flys a little different than earlier versions. We have way too many acronyms already without having to learn about MCAS. (Maximal Casket Allotting System)
Great video as always. Thank you!
Thank YOU for being awesome and watching.
Aerodynamic forces increases quadratically to speed, not exponentially, that’s a big difference.
Thanx, I was going to say something. In any case both terms describe rapid escalation of force required.
Beak ... Plus, we never hear why procedure wasn't followed by disengaging the AutoThrottle.
_
13:46 please do a video about the red button!!!
Its to stop the simulator
@@HarryWhittle2019 thanks 👍
super video petter.. i had the same question about turning... thanks.
Excellent description of the dynamics.
wow good demonstration, are people not shocked that this also happens on a boeing NG? maybe a motor with siwtches up/down to control the trim manually?
Should the electrical motor fail, say 'locking it up'....will manual trim be able to bypass the stuck motor ?
the trim wheels being hard and slow, the manual procedure seems applicable in only few cases for small trim adjustements.
As demonstrated in simulator,
others "run away" cases when plane level is too far out of trim... very limited chance of success. 😂
Why are you trimming forward while pulling back in the sim?
Mental Pilot
To simulate a worse failure, a worse mistrim, before attempting to reverse it at the end.
@@VladimirNicolici Ah. Well, regardless, it seems obvious that the procedures should have the crew trim to neutral stick before killing the electrics if the stabiliser still responds to the toggle on the yoke. From my understanding they don't - and still don't (didn't) in the Max. It also seems inherently dangerous to design a plane where the trimmed control surface cannot be aerodynamically overcome by movement of the elevator/yoke - particularly if it is also impossible to manually trim because the manual backup system lacks the mechanical advantage to do so in extreme circumstances. I realise that direct mechanical control connections are one of the advantages of the 737, but it does seem now that they are less than sufficiently robust to handle the plane in a number of foreseeable scenarios. It's a beautiful little plane - but it's a flying can of hacks and compromises which seem finally to have consumed whatever safety margins were initially built into the design. I think the Max should have been re-certified in the first place, not grandfathered in.
What minimum altitude is required for the rollercoaster/trim manoeuvre?
This would be an emergency procedure with many variables, the only mandatory item being don't hit the ground.
@Thomas Headley ... Why would the overheads be opened? Doesn't make sense for the maneuver shown. It's not a rapid, violent drop like would happen in strong turbulence.
Thanks once again:
I was looking for that video covering "terrain escape maneuver ", I was watching at the end but saw only a call to bank.
what did I miss ?
Wishing you all the best with your health, so you can fly again👍
The trim wheel should have a hydraulic system (with multiple redundancies) so that you can move it while the motor is shut off without applying insane amounts of physical force.
I have a question: at the end of the mis-trim demonstration, you said "Juan, press the red button. Press the red button now!" I assume that aborts the simulation. There seemed to be some urgency in your voice. What would have happened if you had carried on? Is it possible to damage the flight simulator or would it just have become quite unpleasant inside it?
No, I was just exhausted from holding it for so long. Yes, the red button stops the simulation.
This happened today with me I was in a sport cub and the trim got stuck at full down position, we put out flaps to counter it
this is pure diamonds...
11:59 Did he say " do not try this at home " lmaoo!!! Like I have a 737 NG in my garage ! I dont even have a house, leave alone a plane
I'm no pilot, but I am an industrial mechanic. Quick question: Assuming you had the altitude could you not momentarily... Nevermind. I should have watched the whole video before commenting.
"Do not try this at home"
Whaat? I was jst about to go do this in my $100 million dollar aircraft.
Same such a letdown
If the airplane is at sufficient altitude, would it make sense to roll the plane 90 degrees to essentially turn the elevators into rudder? That way, pilots may be able to unload the elevators and trim.
Not 90 degrees because large passanger jets are certified up to bank agle of max 60 degrees. But theoretically yes, if you have enough altitude to play with, significant bank will make manual trim easier.
Concord is the best in the flight
You have to remember that Boeing had intelligent management in 1967. And the employees were totally dedicated to the company. That is no longer the case. Profit and greed is the new case. The Max is a prime example and in conjunction with a mismanaged FAA, the new receipe is disaster no matter what the cost or who it hurts.
I wonder how this works on the Airbus, an A320 for instance. I assume there is no possibility to trim the stabilizer manually using the physical connection?
Olga D. I don't think there is a physical trim handle on the Airbus models.
I wish they had a separate motor to run the stabilizer trim for redundancy. How about fly by wire technology that the Airbus uses? Is the Airbus more advanced and should the Boeing max be seriously updated?
I would like to know the exact force needed to trim the stabilizer like this. I would love to know how hard it actually is. When u lose power steering in your car it can be incapacitating to women or to men who are not physically strong. But a strong, blue collar man will just find it annoying...
They must incorporate a manhole,two seats and two levers beside this jack just in case everything is screwed
Thank you so much Mentour for such an amazing, informative and comprehensive content.. I have a suggestion; what do you think of creating a special website to explain the basics of flying for beginners and freshmen in Aviation Schools? It would be much appreciated.. Your way of explaining is so appealing and i can guarantee the success of this project
That would be interesting
Mentour Pilot It would facilitate the studying and would improve our basic knowledge of aviation and also would prepare many students to their aviation school life and strengthen their knowledge
Is anyone else thinking, why are the stab trim wheels so small? It seems manual trim is almost impossible, especially in an emergency situation ala 737 MAX runaway stab.
Here we are again...
At 15:58, I thought a "bunt" was an outside loop.
Why do the trim wheels turn at different rates and or directions?
I am using the white spots on the trim wheels as a reference.
It could be stretch and rebound in the cables if there are 2 separate ones.
I am impressed that the simulator reproduces the aerodynamic forces on the controls so realistically.
It's impressive. Hard to include the awful sense of jeopardy of a real crisis, though. The screams from the passengers, the panic, the knowledge that if things go badly wrong you WILL die. No reset button. I suppose that's why they pay test pilots so much.
Yup. It's pretty realistic (I think it is a five axis simulator)
they cost like 20 million if i remember correctly
something like that.@@Infiltator2
I was thinking the same thing ....
Who needs a gym when u hav a 737 sim to practice runwaway stabilizer exercise
Cockpit warning: Dog Bored! Play! Play! Play!...Dog Bored! Play! Play! Play!
Back in the days when I was a flight simulator mechanic, I would have been angry at you.
Damn! Flight simulator mechanic....that's a specialty...! 😀
@@henryrollins9177 that's actually what my papa (maternal grandfather) used to do lol
why?
The part I don't understand is why there is no disengage that stops all automatic trim inputs (ex. MCAS) but allows the pilot using the electric motor to trim manually. Car analogy: I touch the brake or shift gears, the cruise control disengages. I can then accelerate, brake and turn manually. The cruise control does not re-engage again. This system as it was built is like a car designed so cruise control can only be disengaged by turning off the engine, losing brake assist and power steering as well.
Great analogy! Spot ON! Only explanation that makes any sense to me is that Boeing ran out of money after paying their CEO & management & shareholders.
Very interesting. Would you consider doing a video of you and your copilot doing the roller coaster maneuver in the simulator?
Not at this point.
If you mean a roll, he has already done that.
kay g And disappear into the earth LOL!
copilot say oh no not me again , i have lost both my arm after this video
at this stage, i reckon that Dog could fly a 737 :D
08:15 - Dog: We already did elevators !!
Dave Fox Is that a stick? Please, please, throw me the stick!
@@stuartmcconnachie Patxi would probably get scared if the stick shaker activated
Patxi is Snoopy's (Red Baron's) girlfriend, also a fighter pilot😁
@@keineahnung6124 Patxi is a boy!!!
@@iangill8984 oops!!,oh well it's 2019,let's not be judgement Al. Lol.
I can see that it is almost impossible to trim any 737 manually further nose-down if the mis-trim is already down. But the BAD situation is that it is IMPOSSIBLE to trim it manually in the REQUIRED direction to save the aircraft, to trim it nose-up. The cranking of ONE pilot can NOT overcome the aerodynamic force that is against the manual trim-up effort. Two pilots would be needed to overcome the limitations of the mechanical (emergency) system. But one of the pilots has to pull the yoke back with all his force and has no free hand to assist the manual trim effort at his side with the second cranking handle. The FAA should look into this too. Why was the 737 NG certified in this DEFICIENT way? The problem was already existing before the 737MAX. Suggestion: The TRIM CUTOUT switches should be changeover switches that disconnect the primary electric trim system that includes the autopilot trim, trim switches at the pilot's control wheel and the electric motor near the jackscrew. When doing the switchover there should be an alternate electric trim system with an alternate (additional) set of trim stitches at the control wheels and a DC-motor in the pedestal which (via a clutch) is able to drive the trim-wheel in the pedestal. The electric DC motor has to have enough torque to drive the (former exclusively manual) system and should be connected to the Emergency DC bus. Second suggestion: FAA should mandate this modification to ALL 737 within six months.
I have no particular interest in aviation, but your videos are always fascinating. Thank you!
Would it make sense in a situation like this to triple-gong the purser so he can work on the captain's side handle of the trimwheel while the captain handles to control column?
‘Dwayne Johnson to the flight deck’.
‘Do not do this at home’ - surely you mean ONLY do this at home 😅.
Juck Norris as copilot would be able to trim the stabilyzer manually in highspeed misstrim situation with his left ear.
We need this to be a series! I could watch these videos 24/7 even though the things I learn here will never apply to me.
You may have to land a plane one day. Its always good to know & not need it than to need it & not know it. In the unlikely event that this happens youll thank your lucky stars & save your life.
Speculation vindicated!!! Speculation is a good thing. We humans and most other creatures have intelligence thanks to intuition which is another word for subconscious speculation that we use when we don't have all the facts. In this video, we have an honest demonstration of a troubling scenario, presented without name nor blame, and not claimed to be any historical fact. It does, however, calibrate our intuition about what may have happened, or can happen in the future.
Thank you so much for showing us the "devil in the details" that is so decisive when things do go terribly wrong. Thank you for getting us intellectually involved in discussing and understanding what ultimately matters in the outcome.
That was an Absolutely Fantastic Video!! Great explanation at the end of why you shouldn't turn to avoid terrain if you don't have visual! Great Stuff!!
EveryTypeOfVideo, do you like Every Type Of Video? :)
@@mauriciomarianocarneiro???
Just a joke cause of the nickname. 🤣😂
🌍🌎🌏 =D
EveryTypeOfVideo - Hi! Yes, you're right. Instrument training is bizarre. The cockpit's blacked out completely, so you can see absolutely nothing but your instruments. Learning to rely exclusively on them when you have (literally) zero visibility is enormously difficult and utterly non-intuitive. It feels totally unnatural.
Your senses are screaming at you that you're banking, or diving, or climbing, or even completely upside-down, but you have to ignore the urge to try to make sense of things. It's very hard to trust instruments alone when flying blind, but it's even harder to reject what your body's telling you to do. When up feels like down and left is 'obviously' right, you have no hope of avoiding disaster without the right training.
Mentour, GREAT VID! I can't help but to wonder what happens to a pilot after a missjudgement like in your "terrain, terrain, pull up" video? Does the pilot file a report and if so what then? Thanks.
Yes, a report is filed and the CVR is retained for a subsequent investigation. What happens to the pilots depends on the investigation.,
0:01 - omg Mento' is giving the yoke the HEIMLICH MANEUVER...!!!
Hahahahaha
No, just happy to have it aboard.
For a non pilot, it is amazing what you go through to fly me to my daughter
Why does a Herkules have 4 AOA sensors and a passenger jet only use one of the 2 AOA sensors? Seems that aviation have been too focused on costs!?
Mentour Pilot, I would like to thank you for addressing the question about terrain escape maneuver and for providing further explanation in this subject. You are doing an absolutely fantastic job with those videos. Keep it going and have a lovely, clear sky.
Thank you! I am really happy you liked it!
The MCAS glitch caused it to take over the horizontal stab and put the plane into a dive. The pilots corrected by switching off the toggle switches to disable the automatic horiz stab control. Question I still have: Why did the pilots switch the toggles back on? Was it because, with the toggle switches off, the hand crank is also disabled, and so they had no choice but to switch the toggles back on to have a chance of recovering from the dive? Even without the horiz trim way out, why would it be so physically strenuous to manual trim using the hand cranks? There's no motor assist for the hand cranks? It's just old fashioned mechanical linkage?
The mechanical backup system is connected to the trim actuators by cables and drums. MCAS had driven the system to the stops using the electric motors and no amount of manual force could overcome the aerodynamic forces at the speed, altitude and elevator positions existing.
@@paulavery366 Part of the problem on the Ethiopian airplane is that the crew never did anything to control their speed, when the aircraft pitched down. They basically went into the dirt at takeoff power. They also didn't cut out the trim system until the aircraft was badly mistrimmed. As a result, the airplane was flying at or beyond its maximum operating speed, and the pilots could not overcome the aerodynamic forces with the manual trim wheels. They likely turned the trim system back on because they believed that only the motors could budge the stabilizer.....which was true, but they would have needed to do things perfectly to recover.
They were likely almost beyond the point of no return. Their only real hope of recovery would have been to get the power to idle, pop the speed brakes, turn the trim system back on and IMMEDIATELY dial in some nose-up trim, followed IMMEDIATELY by again turning off the Cut-Out Switches. If they could get the airplane slowed down and get the stabilizer far enough off the full nose-down position, they might have had a chance to manually trim the airplane......or perhaps go another cycle of turning the trim back on, dialing in a burst of nose-up trim, then turning it back off again.
11:58
DO NO TRY THIS AT HOME!
Me: Cool I won't.
+Good lord, this is a major screw-up in design. This has happened because of newbie designers and engineers and lack of learning from previous generations .
This is confusing: isn’t the copilot trimming the wrong way?? The pilot wants to go up and the copilot seems to be trimming the nose down!
Also, is the roller coaster maneuver even possible? It does not seem to be possible to pull up in order to later let go.
Would reducing speed be better? Would some flaps help?
Pascal ... You have spoken the truth. Now you must be punished.
_
Yes, the copilot attempt to replicate a full nose down trim runaway. After he fails to bring it full nose down he attempts to reverse it and trim correctly at the end. That's even harder, simulation ends.
Lmfaao the toilet-backpressure analogy 😅😂
Hey Mentour, you should do a video about the Stratolaunch plane, largest in the world :)
Coming back to watch your older videos really highlights how much better your English has gotten! Good job
I'm really mind-blown. I don't understand why in a big plane like a 737, a pilot should ever be required to use a big amount of his physical strength on the controls in order to move the elevators, or any other flight control surfaces for that matter.
An electrical engine that weights about 4kg is able to match and exceed any amount of force that a person can exert with his arms. Surely we should have the technology to do that on such a big plane!
Having to struggle with any demanding physical task seems very distracting, and an impairment for pilots that could already find themselves in a high-adrenaline emergency situation.
And considering that male pilots already seem to struggle, female pilots could have even more of a hard time coping with that.
I can understand that the need to apply more pressure on the control stick can provide some useful feedback information to the pilot, but surely it should be possible to employ some servo-assisting technologies similar to the ones employed in modern car steering wheels, so that the pilot could still feel some pressure on the control, yet they would never have to struggle to push or pull the controls.
It’s an old bird. And we are talking some serious non-normals here.
This failure is to account for when the electric motors have failed.
He's demonstrating extreme control forces created by intentionally extreme mis trimming of the horizontal stabilizer. Pilots would not do this intentionally on a real flight. Perhaps test pilots in certification flight tests.
Andrea Chiavazza absolutely correct. I am demonstrating a phenomenon, not a normal occurrence.
Video is 20 minutes long, published 10 minutes ago and yet people are saying nice video etc etc, am I the only person who actually watches this full video?
Some people see the video in x2, so it's possible
I seen this video a day ago 😁. So thats why you probably seen my comment as soon as the video was released.
Patreon Gang where you at?
Patreon supporters get preview, so that's one explanation
@@HossainRonnie And Thumbnail Designers 🙈
Looks to me like the method of applying force to the trim wheels could be designed better, something that gives the pilots more leverage. Seems very clunky, and in an emergency situation could be downright dangerous.
Call any muscular passengers to help with manual trimmimg.
He may be rewarded for some free travel later as a token of acknowledgement of services.
he will be rewarded with survival.
Um... Fair enough idea in theory when everything's nice and calm and measured and logical, but impossible to arrange on a real flight with panicked, screaming passengers, struggling pilots, and a plane plunging towards destruction.
Calling a suitably competent passenger to the cockpit isn't really the same thing as declaring a medical emergency and asking if there's a doctor on board. I think your idea would be the kind of suspiciously convenient Arnold Schwarzenegger 'magic wand' solution you'd find in a big budget Hollywood disaster film. ;-)
You'll break the simulator!
I was worried the machine or copilot was about to break.
Samir
Very interesting. Stressing the incredibly wide speed range of a big passenger jet is vital information for a lot of people who perhaps aren't familiar with aviation. A small plane like a Piper Cub or a Cessna 172 will have a takeoff and landing speed not much different from its cruising speed. So, say, from 75mph up to 140mph (NOT accurate figures, just an example!).
A big jet might cruise at over 500mph, but take off and land at only 130 or so. That's a huge difference. Imagine driving a car without power steering at its top speed of 120mph. Then try it at 240mph. Then 360mph. Then 480mph. The steering forces would be incredible, and very difficult to control.
Air is amazingly thick, dense, 'heavy' stuff at high speeds. It's more like pushing against water, so it's easy to imagine how hard it must be to overcome a big jet's colossal aerodynamic loads without hydraulic assistance or any kind of 'power steering'.
We did that 120MPH in my Dad"s Sprint Car. My XJ12s do 150MPH. Your point is?
Unpowered steering becomes easier the higher the speed.
Not sure what your point is. In the video the elevator control still has hydraulic power assist, which was working well. Power assist always has a taper-off function where there is decreasing assist towards the limit of the movement as well as a reduction of assist with increasing speed. This is to prevent slamming the controls against their mechanical stops with destructive force and to avoid abrupt maneuvering loads that could exceed the strength of the structure or could cause violent maneuvers that jeopardize the mission, e.g. cause a rollover in a car or skidding and loss of traction.
The whole point of trimming is to position the stabilizer so it is doing all the work to hold the airplane in the desired pitch attitude with zero force on the elevator, i.e. for a 737 and other large airplanes, the elevator is in its neutral position, lined up with the stabilizer's chord line, with deflection from that position available to cause quick changes in pitch attitude if necessary.
I was wanting to go to toilet after a big meal and there was a Long queue once, Unfortunately No matter how Hard tried i couldnt apply enough back pressure. I Had to Dump Fuel There and Then !!
That reminds me of a story in my initial pilot training when I was flying a small Cessna cross country (by myself). On those long flights and not having a toilet, I had to use an empty bottle to dump my fluid into. When I lifted the now filled bottle and reached behind to put it back into the cargo area, I had to re-trim the aircraft afterwards. I was surprised that it made a small but noticeable difference.
Another brilliantly informative video, can't wait for the next one!
airbus pilots watching him wrestle the yoke like😂
lmao im a huge boeing fan but watching him put the yoke in a choke hold is hilarious😂
I do wonder why there's no possibility to disengage all systems that automatically trim the aircraft without also disengaging the manual trim using the motor. I can see how being able to physically trim the aircraft is valuable if the motor breaks or can't be controlled anymore but there should be a step in between where only the automatic stabilizer systems are disengaged in my very humble opinion. Can anyone shed any light on this design decision?
@Penny Lane
LOGICAL.
In the end one of the big issues today is pilots need to remember how to
_"Just FLY the plane"_
Spot ON! You nailed it! There should be a new step in between where ALL auto control systems are disengaged but the jackscrew electric motor remains in play controlled by the cockpit up & down trim pushbuttons.
Great action packed video Mentour i enjoyed it, wishing you good health and back to flying soon my friend. Have a good weekend.
Great Job! I'm a ATC at Boston Center for 28 Yrs now.
robert ATC Ah! Montreal ATC is always telling the aircrafts going south east to contact Boston Center, 134,9 ! 🙂
Terminologydoes vary according to application so this is aan observation from my engineering field. I would call a jack-screw as a treaded bar rotating in a simple nut (possibly with a swiveling yoke). Aero applications in my terminology convert rotary to linear motion with a ball-screw instead of a nut. Less friction, less wear and much smoother motion.
Not all aero applications. The reduction in friction and wear that a ball screw has also comes with a greatly increased number of moving parts and paradoxically, decreased reliability, and some aero applications don't need any of that.
Maybe Boeing should add a two speed wheel control (like boat's winches) in case of high speed manual trim operation)
Or require mandatory workout for first officer ;)
there is a trim wheel on each side.
Seems the nature of manual trim wheels make them useful in only a few situations (slow operation, lower air speed, surface load).
Adding a few intermediate gears could make the trim handles EFFORTLESS, right ??
@@glasser2819 With the right gearing, a hex "nut" on the wheel axle, and a handful of charged up Harbor Freight cordless drills (better buy their "premium" brand to pass FAA muster) with matching sockets on them in the cockpit, that should work fine.
It's already slower than automatic trim, increasing the gear reduction would make it eve n slower
re: "require mandatory workout for first officer" 12:37 - DAMMIT LORENZO, PUT YOUR BACK INTO IT...!!!
Seems like a second set of electric trim motors not linked to the automation would of been better than a hand crank. Like they say in the GTA 5 avenger mission "who still cranks?"
Q: At the start if the sim you must have been over-trimmed too much nose down, so you applied backward force on the yoke to nose up. Why then was the copilot trying to increase more nose down trim by moving the trim wheel forwards? Should he not have been pulling it backwards to trim nose up?
Mentour Pilot, or anyone who knows, can you explain the EXACT difference in function of the 2 Stab Trim Cutout switches on the various 737 models? A thread / comment on a machinist forum claims the 737NG has the switches labeled as "Stab Trim Cutout" & "Auto Pilot Cutout" meaning that the Stab Trim Cutout switch deactivates ALL power to electric trim motor but the Auto Pilot Cutout disables ONLY automated trim commands leaving the pilots thumb trim switches functional. So the function of the 2 switches is DIFFERENT. As I understand it--- in the 737 MAX what used to be the "Auto Pilot Cutout" switch is simply labeled as a "Backup" for the "stab trim cutout", both switches have the SAME function and are always operated together. I looked at google images of 737 stab trim cutout switches and indeed I see switches labeled both ways but the pics are not necessarily noted as to which plane version they belong to. In all the discussions about those cutout switches and runaway trim I've not heard any case where one switch would be operated without the other, they are ALWAYS moved together.
Many comments on the recent 737 MAX crashes have suggested there needs to be a way to shut off the automated trim commands but leave the manual electric trim functional. Some even suggesting there needs to be a BIG RED BUTTON to deactivate uncommanded trim inputs. Can it be that earlier 737 versions indeed have this ability? But the MAX does not?
NOTE: couch pilot
the stab trim cutout probably cuts out the switches on the yokes and the autopilot one the autopilot. they're probably always moved together because the pilots are not isolating the fault yet. The "big red button" is probably the AP disconnect switch on the yoke switch is used to quickly cut power to the trim motor. (easer to push) I'm not sure about the differences between earlier 747s and the 747 MAX (again, couch pilot) but I'm pretty sure that's it.
“do not try this at home”😂👍🏼 I will let you know when I have a 737 at home😉
Try borrowing one from work for the weekend. It won't be noticed, right?
gorillaau Ive hide it under the bed so that no one will find it😝
@@ipw68 make sure that you throw a oversized blanket over the tail so no one recognises it.
That is why fly Airbus.... I got 99 problem but trim ain't 1 ;)
@Scott Mayfield Hey master troll who is talking about crashes? Things is that no matter what the situation is you are still going to be able to trim up/down using 1 finger not fighting for dear life. And is not this the point of flying... Controlling the aircraft, not persuading it and begging it ?
@@Nick94M8 how you gonna do that when the trim motor fails?
Flight Attendant comes on the PA and asks: Can anyone fly a plane?
Someone replies: Yes!
FA: What kind of experience do you have?
Person: I watched Mentour Pilot videos!
FA: ...........
in happy news, it's way better than staying at a holiday inn express :)
Another amazing video.
Thank you soooooooo much for the effort so we can understand how pilots work hard so we can enjoy our flight.
Thanks for great videos. I would have enjoyed you getting out of the mis-trim as if it were real and also telling us about the altitude loss as it was going on.
12:27 - memories of hanging onto the column for dear life exactly that whilst training in a Cessna 172
737NG - genuine fly-by-wire :-)
Lmaoo
i believe the newer fly by wire joystick is the oposite of the older fly by cable with a yoke control.
Airbus did away with the weight of some mechanicals and replaced them by mostly reliable software logic
Hahahaha.....cable is also a wire.
Reminds me of the time I took off from Palm Springs in a Cessna 172. There's a mountain on runway heading, which I had been told to maintain, and I felt like departure had forgotten about me, as I got closer to it. I finally asked, "can I turn?", and they said, "Yes, assume own navigation". I turned!
accidents are always a stupid combination of unforseen events.
Two pilots is a great solution for safer flight, right?