As a fan of Luton Town, a football club with an airport close by (London/Luton) I think I should add…we Luton fans are called the Hatters. Cos we made hats in the old days. Who Wants to be a Millinar was first played on television in 1786. Chris Tarrants great great great grandfather hosted it. The prizes also included TB, VD, other letters and malaria. Answer 10 questions and avoid the death penalty and the diseases from those days a d you could have won a hat.
While working as a flying engineer (A&P) sitting in the jump seat on a B737 I was amazed at just how much the flight attendant walking up n down the isle made the elevator trim wheel spin back n forth, even on larger aircraft like the B767 the drinks cart going up n down the isle makes a big difference to the trim.
@@iwatchwithnoads7480 It depends on how heavy the person is and where abouts in the aircraft they are. If they are near the aircraft centre of gravity over the wing, then no. But if they are right down the back or right up the front then it probably would effect it very slightly, but you wouldn't be able to feel it. The aircraft autopilot is very sensitive and can make tiny adjustments to keep the aircraft level.
When I first saw this video was 21 minutes long. I thought you were going to talk about a bunch of nonsense for 15 minutes. Before giving a simple explanation of what the spinning things were for. Instead everyone and I got an in depth lesson on what they are, what they do and how they work. From the start of the video until the end. Very informative and explained very well. I watch too much Simon W. You and Kelsey (74Gear) are the best.
If he keeps making videos like this about aircraft systems, I think even as a line training captain he'll someday be out of a job... "So, where did you learn your way around a cockpit?" "Mentour Pilot..." "Ah, yes. Great content on his channel. You're hired. You're starting next monday. Would you like to be first officer or captain?" On a serious note though, this knowledge could possibly save lives in a case both pilots get incapacitated. Someone who's got some basic knowledge about the cockpit, where everything is, and how the plane should behave, could in such case possibly get her on the ground with less damage and injuries than if you just let her do her own thing.
@@joffreyverbeeck1640 It’s a nice idea but if both pilots get incapacitated then everyone on board is doomed. Even if there were someone on board who either is a pilot or knows enough to call ATC to get them to get someone to teach them how to program the autopilot to land, the sad truth is that it wouldn’t matter. Because thanks to the events of 9/11 it’s incredibly difficult to even get into the cockpit because the doors have been reinforced and are always locked. I’m honestly unaware of the exact security precautions involved in cockpit door but I don’t think any normal person could gain access even in such an emergency like that.
@@mikoto7693 In one of the videos on RUclips it is mentioned that It's an open secret that there often is one person in the flight personnel who has the number combination to enter the cockpit. This was introduced after the tragedy of the Germanwings flight, if memory serves. A group of terrorists would have some problems in torturing one by one the flight crew members in order to extract from them the combination to gain access to the cockpit.
Alaskan airline flight 261 would be a perfect example of catastrophic failure in the horizontal stabilizer. For those who aren’t familiar with that incident, it was a MD-83 that went down off the California coast in 2000. It was determined that the airline delayed maintenance on the jackscrew in an attempt to save money, but they delayed too long. The jackscrew ran out of grease resulting in the threads to stripping out. This eventually caused the plane to go into an unrecoverable dive and loss of aircraft with all hands.
There were 2 factors that contributed to this. When the screw ran out of grease and it was stuck, the pilots used 2 motors instead of one in an attempt to turn it. That was too much for the damaged thread to handle. But the scariest part of this was the M-D engineering. After the thread stripped and the stabilzer hit its down limit, the pilots managed to level off at around 19,000. That was until the down limit nut failed and the stablizer went past the down limit. Had M-D designed it to be fail safe, had there been a bigger nut at the down limit, the pilots might have made it as LAX was in sight
@@chunkyazian There's no denying that there should have been a fail safe and that the pilots using two motors in an attempt to force the jackscrew ultimately caused it to fail completely. The root cause was the airlines negligence in properly maintaining the jackscrew which resulted it premature wear allowing the failure to occur.
Like @Felix C it was multiple factors. If the screw jack on the 737 fails the Hstab can't travel past the limits like the DC9/MD8x could. Additionally inspection is easy as the jack is in the tailcone not inside the tail. The design is very different as the arm will get trapped between bottom gimbal the safety nut which unlike the DC9 is huge. Finally the pilots sadly did the unthinkable after 2nd or 3rd event. They tried to use the trim again (like normal). If they would have left it and limped back to LA they would have survived.
It always blows my mind how many redundancies are built into aircraft. I get why it is, and I am so thankful it is, but you guys work work with so many safeties built in. It’s really cool. No human is perfect and I know at the end of the day, if you keep you alive, you keep us alive. Much respect.
Ahh, the good ol' fire gloves. There was a giant hangar with a row of lights out because one light was tripping the circuit breaker. The apprentice complained he had no way of knowing which light was faulty without inspecting each one. The head electrician puts on a fire glove and holds down the circuit breaker until one light explodes - "that's the one!". 🤣
Oh yes, for doing that, you HAVE to know your wiring very very good, otherwise it is perfectly possible that some other part of the wiring goes off before the faulty light... in which case you have not found the faulty light but the weakest wire... There is quite some margin between the cb's tripping and wire failing, but it is not impossible. And that's the reason we should never test it, even don't suggest doing something like that, bcse people who have NOT enough knowledge (about the circuit, and/or generally) get the impression they could or even should try that too (and get fcked while doing so). Besides, i know a whole line of circuit breakers where holding the lever up would not stop it from tripping...
3 years ago and it was my 2nd lesson in a B 737 full flight simulator from Lufthansa Flight Training in Berlin. At some point my flight instructor asked why I was trimming so often. I told him because I like the sound of it so much. Have a nice Christmas Time too. 😃🎄🎁
Hi Mentour thank you for your videos im watching this one probably 3rd time and it got me thinking from investigations of lion air and ethiopian air 737 max did the pilots try or have enough time to try and use the manual elevator trim to avoid the fatal pitch down?
I was in a DeHavilland Buffalo that was on a return flight From Anchorage, destination Comox. It had a manual unassisted elevator trim wheel in this aircraft with no autopilot. There were a dozen crew in the back and after a few hours of boredom, everyone quietly moved as far aft as possible, and we watched the pilot compensating automatically as his hand hung down casually, just moving the wheel. We all moved forward, and we giggled as we watched him moving the wheel. After three or four times, his head came up as he realized what was going on. He looked back at us, and pushed the stick hard forward, we all got thrown to the floor, and as he pulled hard back, we all flew up into the ceiling, then all falling down. Everyone had a giggle, but we all learned not to mess with the pilot.
I had a flight instructor on a Cessna 150 who didn't show for some reason. He was replaced with another who happened to also be a fighter pilot. He decided to demonstrate rolls and dives. A good thing I don't eat prior to flying. I stopped him reminding him we were a bit low on oil. I could imsgine doing a roll and starving the engine of fuel and it cutting off midair. It happened once before, no acrobatics.I guess he was showing off but the next time i rode with a hotdog was in a car going to another airport in St. Louis.teaming rain, night. Doing 85mph. I prayed & got there in one piece.
@@sharoncassell9358 We used to call fighter pilots "Kerosene Cowboys". But to be a successful fighter pilot you have to have that wild aggressive streak in you. If not, go fly transports.
Thanks. Always love your reports. My 22yr old granddaughter has just passed her PPL at flight school at Bankstown Airport in Sydney. She is now doing CPL so I have added interest in all things aviation. Many thanks 🇦🇺👍
You put it all together for me, thank you. I know what ship stabilizers do, but did not know that wing stabilizers actually work in a similar way. So happy to finally understand this!
I can't adequately express how mch I enjoy your content @Mentour Pilot! I stumbled onto one of your videos while scrolling on Facebook and I was instantly hooked by your in-depth analysis of the flight investigations. This had a huge imact on me, not only because it completely changed the light that I see airline pilots in, but it also made me realize just how much I am interested in aviation. Your videos have helped me realize something I'm passionate about and I eventually hope to recieve my type rating!!!! Much love and even safer travels!!!
A brilliant explanation. I always knew about the trim, but only the essentials, not the details. Thank again for taking your time to explain the physics of the trim and issues that can arise. I know it’s important to keep the trim Jack greased as well.
Went into the video knowing that they're the trim wheels for adjusting the pitch trim, wondering how that was going to be a 20 minute video. Got WAY more information than I expected, including the mechanisms involved. Wow... awesome job!
@@Biggles2498: Oh! Yeah, OK, that makes sense! Haha, duhhh (on me)! I asked because so many dimwits try to use quotes for stuff they weren't intended for, like emphasis. Speaking of using things for the unintended, why go out of your way to hit "shift" before every word?
@@HelloKittyFanMan. Well I had to hit the Landing Gear Lever every time I intended to land my aircraft ....it would have been expensive and dangerous not to do so.
I am way behind on Mentour Pilot, just found this channel a few weeks ago and love it! I am not a pilot but as a mechanical engineer I've always been very curious about airplanes. Despite having a good understanding of aerodynamics I've learned a ton and the best part is my fear of flying has improved! Thank you so much!
I remember in Spartan College (aviation school) Instructor told us a story in class, of a prank they did to the pilot. They had a crew in back of the plane move back and forth from back of the plane to the front. Pilot was like wft is going on!!! I have to change pitch/trim all the time.
You are probably the only person on the whole internet who can make a 21 minute video about the 737 trim system and have the entire thing be interesting!
Another feature of the stab trim wheels is that if you really hate your knees for some reason, you can leave those handles on the wheels out when the aircraft is on auto pilot. That way, you can automate bashing of your knees using the stab trim wheel handles.
I don't fly, but this stuff is fascinating to me. I have been searching RUclips for what "trim" means in aviation. A video like this one reminds me of the frightening prospects of things that can go wrong in one of these massive man-made machines.
When I was a kid, I built and launched model rockets. I remember one of the primary rules of rocket physics was that the center of pressure must be behind the center of gravity. The farther apart these two points are, the more stable the rocket will fly. The fins move the center of pressure to the rear/bottom of the rocket. Adding mass/weight to the nose moves the center of gravity toward the front/top of the rocket.
When I did my initial upgrade training in the 737 we were told that in order to stop a runaway trim just reach over and pull the FO‘s leg into it. Preferably with the handle extended.
Thank you Mentour Pilot, I'm sure this helped some people to understand the trim, but since I know that all this info doesn't fit into everyone's head I have a message for them. Let's say we are driving a car in the highway and of course we want it to go straight. But the roads they are not flat and leveled because the water from the rain needs to drain away from the road surface. So, the roads could be either higher in the middle and lower on the sides or lower on one side and higher on the other. The front wheels of the vehicle are trying to turn toward the lower side. In other words the car does not want to go straight but it pulls slightly to that direction. To compensate for that, you apply a little pressure on the steering wheel toward the opposite direction and you hold it there and this way you are forcing the car to go straight and not toward the curb, the ditch. What you just did is you "trimmed" the wheels of the vehicle. In the same manner, the pilots adjust the aircraft's aerodynamic controls in a way to compensate for the deviation from their route due to winds and other weather conditions that push the aircraft left or right or up and down. I will not provide any further technical details nor what the aircraft systems do to help out the pilots to lighten their workload because that's the job of the Mentour Pilot.
You also loose alot of finess from the horizontal stab when you need to use a big elevator angle. That's why the first way to fix the trim is to move fuel forward and backward to keep a neutral elevator angle. That's also why it's more efficient to keep the entire profile streamlined by pivoting the entire wing.
This Channel is much better then discovery channel, which i loved to see when i was a teenager, incredebel welll spoked, incredebel good to explaine, if i understand all this then anyone does too, RESPECT to you sir. And thank you so much for all this videoes. Mr ioan from Denmark
You mentioned quite a few times about the spinning things getting jammed and how to manually turn them but how often does that happen? Have you personally ever encountered that situation and wondering whether at that moment of urgency (noticing the failure) is it really possible to focus on manually turning them?
The nut broke because it had not been properly lubricated. In part this also happened because the flight crew went outside of SOP and tried to fix the stab trim by activating both trim motors at the same time.
I'd have thought in the case of runaway trim instead of having to hold the wheel with your hand there could be say a small metal bar you could slide into the wheel to physically stop it moving. Of course, I've no idea how common a runaway trim situation is so it may not be financially feasible to build this into the trim-wheel mechanism. As always excellent video Petter and beautifully explained, I love these type of explanation videos you do.
Just reiterates further why pilots don't want people up and moving all around while during takeoff I guess, they'd have to keep constantly readjusting trim if that were the case, and they got enough things to worry about at that time already. This is such a good channel even for people that aren't pilots, that just enjoy learning like I do
Awesome vid! I have long wondered, but been to shy to ask! I feel I understand so much more now. I have long wondered about the MCAS failure on MAX, and now get much more how integral the jack screw stabilizer movement is to flying the plane. I need to AMP up my home sim and try to learn more. (Trim input on my hangglider is all manual :-) )
I did wonder what they were there for during the “could a passenger be talked through landing a 747” video. In honesty in that scenario even in a flight simulator I’d be so tense and anxious that when they first span around in my presence I wouldn’t have been expecting it and almost jumped out of my skin. That being said, I’m surprised that my guess on their function wasn’t actually that far off as I figured they probably were some kind of manual control just in case the computer took inspiration from my PC at home and just stopped working for no apparent reason. Which, given my closest experience to piloting is when I stole a fighter jet in one of the Grand Theft Auto games, wasn’t a bad guess.
Glad I watched this video. I've been watching a lot of aviation videos (on this channel and others) and kept hearing the term "trim" but didn't understand what it was or what it did. I had a basic understanding of elevators, rutter, etc...but just not the trim. Thank you for such a clear (and detailed) explanation!
An accident with Alaska Airlines happened because of a vertical trim failure due to maintenance scheduling issues. The airplane had not been serviced properly and the jack-screw was not properly lubricated. It then got stripped and came out of the nut that connected it to the horizontal stabilizer and the pilots lost control of the pitch of the aircraft. Not a good thing.
@Jim Mork There have been countless examples of cars crashing into mountains or plunging into water. Drowning is never a pleasant way to die. If a plane crashes into water usually people die quick and painless.
@Jim Mork no intention to argue about that,but you can google for the toyota trhottlegate case.a bug in the code of some toyota models who make the car suddenly go full power. not a faulty sensor or similar,a real program bug that make the car go full throttle.
@Jim Mork there was quality control staff who got fired because they found they were using substandard parts,making them fit by drill and hammer,specially the wing forks,those who later needed replacement and much more parts.there is no regulators actually,boeing certifies itself their own airplanes and the regulator just accept the incoming documentation,without test or verify nothing.thats why they are not more the standard for the rest of the world like before.there are documentarys here on YT,and they seem legit. The toyota case,it seems the code was a pretty nasty mess,plagued with patches over patches never cleaned.finally they accept to pay to the US goverment on the condition to not look further. dont know who is worse.
Excellent explanation. I am a flight dispatcher. I never really understood stab trim other than it being a number we work out on the trim chart, but now it makes sense.
I always thought they were fidget spinners for the pilots to play with when they get bored. Seriously though, trim is equally important for RC cars. When you've got a toy car going 60 miles an hour with less than half an inch of ground clearance, the car is capable of veering off-course and smashing into a curb (or someone's ankle -- or face, if the car catches the air and turns into a kite -- yes that can actually happen) before you even have time to realize something is going wrong. So you have to trim the steering accurately enough that you can punch the throttle and accelerate all the way to top speed with minimal steering input, or else the car will be too unstable to actually drive.
In your RC car example, is it not rather like a deadzone setting, more than a trim ? (you make the deadzone bigger, so that little impulses on the stick are not registered, where a trim acts as a force, and moves the center of an axe in one direction, so that if you release your hand or thumb from the remote, it centers on a value different than the original untrimmed zero value, in your case the RC car would then have a tendency to turn, as a real car with bad wheels geometry). If it is a trim in the case of RC cars, is it because the small car has an issue of wheels geometry, or because of outside factors ? (such as wind, or the track geometry)
Most wires go way back. The motor in the floor behind pilots seat controls movement in the tail. Hydraulics reach all the way back to operate systems plus landing gear. There are2 actuator pumps which activate to pump hydraulic fluid to systems.
I'm just hitting every video in my recommended using "Open in New Tab" to wish everyone a happy and safe end to 2020! Love all of you (even if I've argued with you). Be safe, be well, know you're loved, let's work our asses off to make 2021 a little less... grim. No matter your deity (if any), we are humans... let's stop acting like it and actually come together for a better world.
The same to you, Jeremy. Let's see if we can make 2021 better. Since 1200 BC we've had more than 250 epidemics and we're still here. This latest virus won't take us out either. It WILL take out the elderly and those with a compromised immune system.
I worked for an airline that used to build their own B727 cockpit procedures simulators. The simulators had no motion as it was only for familiarizing new pilots with cockpit procedures and switch locations. The guys who made the simulators used cake pans painted black with white stripes for the pitch trim wheels. As a result all the pilots and mechanics called them pie pans.
Thanks for the very informative n intresting vdo. Due to Covid my air travel has completely stopped. But still curious about planes I started watching vdo's about planes and got attracted to air crash investigation's, but didn't knew the technical details. This video cleared me about trimming the aircraft. subscribed!
Lol, imagine the “could a passenger be talked through landing a 747” scenario and when those spinney things first moved, them managing to freak the poor unsuspecting bastard out. I could take a pilot dumbing things down to my level.
A lovely video, as always. Is this in response to the Max entering service again? Or are you at liberty to explain why you are revisiting this subject? (Not that you really need much reason. The trim system is surprisingly fascinating.)
It is a weird video. There is obviously no mention about Max as if the pilots were not allowed to talk about it anymore. It sounds and looks like some Boeing promo video. The airlines using them are probably counting on that people will not be asking about the aircraft type after lockdowns are finally lifted being happy to be able to fly somewhere at all. But I think that the whole era of cheap flying in cramped economy class represented by obsolete 737 is over. People will be willing to pay more for their safety and comfort and the bet on Max entering the service again as if there was no pandemic is wrong.
In basic flying school, the trim is used to maintain airspeed. When the aircraft is properly trimmed, the thrust setting decides the aircraft climb or descent rate and the nose angle changes to maintain the same airspeed. So Pitch, power and trim.
The fact that they reuse the same warning sounds for different things (takeoff configuration and cabin altitude) really bothers me - there's no reason these days that they couldn't have a distinct sound. Confusion about the meaning of that sound was a contributing factor in the crash of Helios flight 522.
While this is true. Typically the alarms that are shared can either only be set off in the air or on the ground. I.E. if youre in the air it can only be one of the two. And if youre on the ground it can only be the other.
Kerbal Space program (which also does planes) is pretty good for learning about the center of mass and gravity and how to use and not use them. Messing this up is usually the most common beginner mistake. Scott Manleys old Beginners Guide to Aircraft Aerodynamics saved a lot of kerbal lifes for me. and at the same time gives a great and visual idea about how it actually works (simplified).
I changed a trim motor in the floor and a t tail elevator motor up in the tail a narrow space they call hell hole. I didn't understand exactly what it did but 2 years later when I took up flying I learned and now reiterated more significantly its purpose.
Super film 👍👍🙂🙂 I finally know what those turning wheels in the airplane cabin are for. I've always been curious what purpose they were placed there for. Thank you very much for a good technical lecture. Greetings from Poland
Supposing many aircraft in a holding pattern at a busy international airport. What is the standard response when communication from ATC is completely cut?
If all trim and control system fails and stucks, is it possible to fly or land or turn the plane if full of obeying passengers (in theory) just by ordering them to go to the left/right side of the plane or if everyone moves/runs to the front/back of the plane or somewhere inbetween assuming they can go to the proper spot perfectly and instantly? :) Can they mess up the landing by running around and jumping in sync, and if yes then how much? :)
Yes I think you can. - Though it would be far more for elevator trim than roll trim because of the shape of the cabin.. The big problem though is that passenger control response time tends to be pretty slow. (which then tends to lead to things like uncontrollable feedback oscillation..)
As a simulator tech in the Air Force, I was assigned to a KC-135 (Boeing 707) simulator. During some of the practice "missions", the instructor pilot would cause the trim wheel to run away. Although crude, the solution to that situation was to grab the wheel and prevent it from spinning. That wheel is turning with a fair amount of torque and the co-pilot would have to stop it with his bare hands.
I always wondered about the spinning wheels as well. Glad you explained this. I did not know the complete stabilizer moved as well. I thought it was just the elevator. Was a runaway jackscrew the reason for the Max crashes? Just asking.
1 There is not the elevator, is the horizontal stabilizer, not the same. 2 the max crashes happened beacause a software error in the Maneouvering Control Argumentation System.
Well if there's no assigned seating, they will move people if there's not enough people evenly distributed. Even on flights where they do have assigned seating, I once got a change of seat at the gate because there weren't enough people sitting in the back (the flight had only like 20 people in it)
How much effect does passenger seating have on the balance? How about cargo? How do you know the exact weight of all of that? (I imagine cargo is weighted and distributed accordingly) Who guarantees that the cargo is properly placed and distributed on the cargo hold?
Military have loadmasters to help balance cargo. Flight engineers to help calculate the fuel usage. Modern planes eliminate flight engineer & have many automated systems to compensate.
@@sharoncassell9358 I didn't ask about fuel. The flight crew calculates that. Commercial aviation is not a military operation, with abundance of money to waste. 🤔 So you answered a question that wasn't asked.
Literally only one person in the world could talk about trim stabilizers for 21min and keep me engaged. Hats off to you, sir!
I do agree. 100%. 21 min.
Agreed, am not even close to being a pilot :) //
As a fan of Luton Town, a football club with an airport close by (London/Luton) I think I should add…we Luton fans are called the Hatters. Cos we made hats in the old days. Who Wants to be a Millinar was first played on television in 1786. Chris Tarrants great great great grandfather hosted it. The prizes also included TB, VD, other letters and malaria. Answer 10 questions and avoid the death penalty and the diseases from those days a d you could have won a hat.
Indeed. I have binge watched his whole channel back to 3 years within 3 weeks 😀
@@jamisbillson4872 lol
While working as a flying engineer (A&P) sitting in the jump seat on a B737 I was amazed at just how much the flight attendant walking up n down the isle made the elevator trim wheel spin back n forth, even on larger aircraft like the B767 the drinks cart going up n down the isle makes a big difference to the trim.
What about someone jumping up and down?
@@iwatchwithnoads7480
It depends on how heavy the person is and where abouts in the aircraft they are.
If they are near the aircraft centre of gravity over the wing, then no.
But if they are right down the back or right up the front then it probably would effect it very slightly, but you wouldn't be able to feel it.
The aircraft autopilot is very sensitive and can make tiny adjustments to keep the aircraft level.
you should see the difference when I flush.
@@iwatchwithnoads7480 Someone jumping up and down has the same weight on average as someone doing nothing. Unless the autopilot is reacting within the
@@ElectricityTaster nasty!
When I first saw this video was 21 minutes long. I thought you were going to talk about a bunch of nonsense for 15 minutes. Before giving a simple explanation of what the spinning things were for. Instead everyone and I got an in depth lesson on what they are, what they do and how they work. From the start of the video until the end. Very informative and explained very well. I watch too much Simon W. You and Kelsey (74Gear) are the best.
In
If he keeps making videos like this about aircraft systems, I think even as a line training captain he'll someday be out of a job...
"So, where did you learn your way around a cockpit?"
"Mentour Pilot..."
"Ah, yes. Great content on his channel. You're hired. You're starting next monday. Would you like to be first officer or captain?"
On a serious note though, this knowledge could possibly save lives in a case both pilots get incapacitated. Someone who's got some basic knowledge about the cockpit, where everything is, and how the plane should behave, could in such case possibly get her on the ground with less damage and injuries than if you just let her do her own thing.
@@joffreyverbeeck1640 It’s a nice idea but if both pilots get incapacitated then everyone on board is doomed. Even if there were someone on board who either is a pilot or knows enough to call ATC to get them to get someone to teach them how to program the autopilot to land, the sad truth is that it wouldn’t matter.
Because thanks to the events of 9/11 it’s incredibly difficult to even get into the cockpit because the doors have been reinforced and are always locked. I’m honestly unaware of the exact security precautions involved in cockpit door but I don’t think any normal person could gain access even in such an emergency like that.
Agreed! Him and Kelsey are on top
@@mikoto7693 In one of the videos on RUclips it is mentioned that It's an open secret that there often is one person in the flight personnel who has the number combination to enter the cockpit. This was introduced after the tragedy of the Germanwings flight, if memory serves. A group of terrorists would have some problems in torturing one by one the flight crew members in order to extract from them the combination to gain access to the cockpit.
Alaskan airline flight 261 would be a perfect example of catastrophic failure in the horizontal stabilizer. For those who aren’t familiar with that incident, it was a MD-83 that went down off the California coast in 2000. It was determined that the airline delayed maintenance on the jackscrew in an attempt to save money, but they delayed too long. The jackscrew ran out of grease resulting in the threads to stripping out. This eventually caused the plane to go into an unrecoverable dive and loss of aircraft with all hands.
There were 2 factors that contributed to this. When the screw ran out of grease and it was stuck, the pilots used 2 motors instead of one in an attempt to turn it. That was too much for the damaged thread to handle. But the scariest part of this was the M-D engineering. After the thread stripped and the stabilzer hit its down limit, the pilots managed to level off at around 19,000. That was until the down limit nut failed and the stablizer went past the down limit. Had M-D designed it to be fail safe, had there been a bigger nut at the down limit, the pilots might have made it as LAX was in sight
@@chunkyazian There's no denying that there should have been a fail safe and that the pilots using two motors in an attempt to force the jackscrew ultimately caused it to fail completely. The root cause was the airlines negligence in properly maintaining the jackscrew which resulted it premature wear allowing the failure to occur.
I worked with one of the victims.
@Jim Mork I can't even imagine the terror that everyone on that plane went thru when it inverted.
Like @Felix C it was multiple factors. If the screw jack on the 737 fails the Hstab can't travel past the limits like the DC9/MD8x could. Additionally inspection is easy as the jack is in the tailcone not inside the tail. The design is very different as the arm will get trapped between bottom gimbal the safety nut which unlike the DC9 is huge. Finally the pilots sadly did the unthinkable after 2nd or 3rd event. They tried to use the trim again (like normal). If they would have left it and limped back to LA they would have survived.
It always blows my mind how many redundancies are built into aircraft. I get why it is, and I am so thankful it is, but you guys work work with so many safeties built in. It’s really cool. No human is perfect and I know at the end of the day, if you keep you alive, you keep us alive. Much respect.
Ahh, the good ol' fire gloves. There was a giant hangar with a row of lights out because one light was tripping the circuit breaker. The apprentice complained he had no way of knowing which light was faulty without inspecting each one. The head electrician puts on a fire glove and holds down the circuit breaker until one light explodes - "that's the one!". 🤣
Oh yes, for doing that, you HAVE to know your wiring very very good, otherwise it is perfectly possible that some other part of the wiring goes off before the faulty light... in which case you have not found the faulty light but the weakest wire...
There is quite some margin between the cb's tripping and wire failing, but it is not impossible. And that's the reason we should never test it, even don't suggest doing something like that, bcse people who have NOT enough knowledge (about the circuit, and/or generally) get the impression they could or even should try that too (and get fcked while doing so).
Besides, i know a whole line of circuit breakers where holding the lever up would not stop it from tripping...
@@SYNtemp I'm reasonably sure in this situation the wiring was extra heavy duty, metal cased etc. The location was a steel processing factory.
I work in an aerospace factory and I would never think of doing something that insane.
@@JoshuaTootell my first thought is how would you explain that to your boss if something went wrong lol
@@SYNtemp Very good point. It takes a very knowledgable expert to do dumb shit safely.
The term "trims" in all airflow-able crafts are so similar in functionality. The trimming of the sails comes to mind. Nice presentation.
3 years ago and it was my 2nd lesson in a B 737 full flight simulator from Lufthansa Flight Training in Berlin. At some point my flight instructor asked why I was trimming so often. I told him because I like the sound of it so much. Have a nice Christmas Time too. 😃🎄🎁
finally I know what those wheel things do!
Excellent! That was what I was after 😂
Same here 😂😂😂
@@MentourPilot You mean they aren't the manual starter for the engine? :p
@@TheSackese No, they are the kick starter for the engines!
Hi Mentour thank you for your videos im watching this one probably 3rd time and it got me thinking from investigations of lion air and ethiopian air 737 max did the pilots try or have enough time to try and use the manual elevator trim to avoid the fatal pitch down?
I thought they were emergency power generators with hamsters inside.
😂😂
No! they are not, they are emergency power generators with kittens inside.
@@henkbarnard1553 mini horses
@@andreaskavak2364 Neigh can't be that.
The Max 8 did, the trim had a mind of its own.
I was in a DeHavilland Buffalo that was on a return flight From Anchorage, destination Comox. It had a manual unassisted elevator trim wheel in this aircraft with no autopilot. There were a dozen crew in the back and after a few hours of boredom, everyone quietly moved as far aft as possible, and we watched the pilot compensating automatically as his hand hung down casually, just moving the wheel. We all moved forward, and we giggled as we watched him moving the wheel. After three or four times, his head came up as he realized what was going on. He looked back at us, and pushed the stick hard forward, we all got thrown to the floor, and as he pulled hard back, we all flew up into the ceiling, then all falling down. Everyone had a giggle, but we all learned not to mess with the pilot.
I had a flight instructor on a Cessna 150 who didn't show for some reason. He was replaced with another who happened to also be a fighter pilot. He decided to demonstrate rolls and dives. A good thing I don't eat prior to flying. I stopped him reminding him we were a bit low on oil. I could imsgine doing a roll and starving the engine of fuel and it cutting off midair. It happened once before, no acrobatics.I guess he was showing off but the next time i rode with a hotdog was in a car going to another airport in St. Louis.teaming rain, night. Doing 85mph. I prayed & got there in one piece.
@@sharoncassell9358 We used to call fighter pilots "Kerosene Cowboys". But to be a successful fighter pilot you have to have that wild aggressive streak in you. If not, go fly transports.
I've heard you mention "trim" in lots of other videos, but I never really understood what it was. Thanks for explaining it so well.
This one is in my top 3. I learned a lot here Petter. Thanks for the content!
Thanks. Always love your reports. My 22yr old granddaughter has just passed her PPL at flight school at Bankstown Airport in Sydney. She is now doing CPL so I have added interest in all things aviation. Many thanks 🇦🇺👍
This video is just brilliant. It also explained why the pilots might have not known how to deal with the 737 Max MCAS issues.
You put it all together for me, thank you. I know what ship stabilizers do, but did not know that wing stabilizers actually work in a similar way. So happy to finally understand this!
I knew the answer before you stated it, having never flown a plane or used a simulator, because you're a great teacher.
Thanks for bringing back my fond memories of working in a USAF undergraduate Pilot Training school.
I remember asking a pilot what those wheels were as I didn't know. He explained it to me (about a year ago).
Kudos My Friend,
A presentation of excellence as always.
Your efforts are very much appreciated in Pittsburgh Pennsylvania, USA.
They are levers for chemtrail dispersion obviously. Everybody knows that.
:) :) :) 😂😂😂
Hahaha
🤣
🤣🤫
Aren't they now dispersing those 5g-microchip infused covid vacine with them?
@@bg2junge Precisely. 😂
I can't adequately express how mch I enjoy your content @Mentour Pilot! I stumbled onto one of your videos while scrolling on Facebook and I was instantly hooked by your in-depth analysis of the flight investigations. This had a huge imact on me, not only because it completely changed the light that I see airline pilots in, but it also made me realize just how much I am interested in aviation. Your videos have helped me realize something I'm passionate about and I eventually hope to recieve my type rating!!!! Much love and even safer travels!!!
A brilliant explanation. I always knew about the trim, but only the essentials, not the details. Thank again for taking your time to explain the physics of the trim and issues that can arise. I know it’s important to keep the trim Jack greased as well.
You should’ve worn your “This is how I Trim” t-shirt. Great video!
My lovely daughter in law flies 737s. I had no idea she needed to be so strong! Love the videos. Thank you.
(19:36) "... if the trim keeps spining, that means you're flying a B737 max" ^^
"What are those SPINNING things in the cockpit?!" - they are the wheels of doom.
Went into the video knowing that they're the trim wheels for adjusting the pitch trim, wondering how that was going to be a 20 minute video. Got WAY more information than I expected, including the mechanisms involved. Wow... awesome job!
"If you know a little about physics...."
Yes - I am _that_ dangerous!
atticstattic : you need AT LEAST "A" Level Physics to become an Airline Pilot Sir or Madam !
@@Biggles2498: Why is the "a" in quotes? Is it not _actually_ one level? And why is every word a brand to you?
@@HelloKittyFanMan. For the benefit of the uneducated "A" stands for "Advanced" ie Advanced Level Physics like done in the 6th Form at School.
@@Biggles2498: Oh! Yeah, OK, that makes sense! Haha, duhhh (on me)!
I asked because so many dimwits try to use quotes for stuff they weren't intended for, like emphasis. Speaking of using things for the unintended, why go out of your way to hit "shift" before every word?
@@HelloKittyFanMan. Well I had to hit the Landing Gear Lever every time I intended to land my aircraft ....it would have been expensive and dangerous not to do so.
I am way behind on Mentour Pilot, just found this channel a few weeks ago and love it! I am not a pilot but as a mechanical engineer I've always been very curious about airplanes. Despite having a good understanding of aerodynamics I've learned a ton and the best part is my fear of flying has improved! Thank you so much!
I remember in Spartan College (aviation school) Instructor told us a story in class, of a prank they did to the pilot. They had a crew in back of the plane move back and forth from back of the plane to the front. Pilot was like wft is going on!!! I have to change pitch/trim all the time.
they do that on subs, too.
I had exactly this question after watching another Mentour video!
Thank you for helping me to learn so much about what pilots do.
Hey Mentour, i just wanted to let you know I really love your videos and I think you are an amazing person!!
All the best!!!
You are probably the only person on the whole internet who can make a 21 minute video about the 737 trim system and have the entire thing be interesting!
Hi Captain Petter, this fits in nicely with the video you did about the trim problems encountered by the two crashed 737 max's
Oh, that explains why “runaway trim” sounded so familiar. I must have heard it from a 737 max documentary.
Another feature of the stab trim wheels is that if you really hate your knees for some reason, you can leave those handles on the wheels out when the aircraft is on auto pilot. That way, you can automate bashing of your knees using the stab trim wheel handles.
The pillows at Your sofa are also very OK. The red one on the left hand the green on the right;)
😉
Way cool explanation! Anyone who has driven a motorboat understands the principle of trimtabs which trims the boat to keep it level.
I feel like I’m getting a you tube type rating.
Go flying. It’ll help.
I had 15 type ratings but I suppose I have 16 now thank you Michael Pare !
i use the type rating to fly my MSFS 😀
lol
I always asked myself about those moving "disks"; thank you, very helpful information!
"If you're not clacking, you're slacking."
- 74 gear
You just answered the question I asked you in the video I watched before this one. Thank you.
I always thought that they were some kind of angle grinder intended to prevent the pilots from falling asleep and letting their knee touch it...
@@seanthompson258 "Plane site" 🤣😂You are hilarious!
@@seanthompson258 if the earth is a plane who flies it?
@@seanthompson258 plane sight x) if the earth is flat how can a plane fly from usa to japan? Where is this edge? x)
Thank you for the great explanation....
I don't fly, but this stuff is fascinating to me. I have been searching RUclips for what "trim" means in aviation. A video like this one reminds me of the frightening prospects of things that can go wrong in one of these massive man-made machines.
When I was a kid, I built and launched model rockets. I remember one of the primary rules of rocket physics was that the center of pressure must be behind the center of gravity. The farther apart these two points are, the more stable the rocket will fly. The fins move the center of pressure to the rear/bottom of the rocket. Adding mass/weight to the nose moves the center of gravity toward the front/top of the rocket.
Great comment. 👍
O, yes, did the same as a kid and even as a student. Long time ago, but good memories!
You certainly learn the same thing the hard way playing Kerbal space program.
@@Lucien86 Indeed! KSP is one of my favorite games!
When I did my initial upgrade training in the 737 we were told that in order to stop a runaway trim just reach over and pull the FO‘s leg into it. Preferably with the handle extended.
So those switches on the wheel aren't volume up and volume down. 😀
Nice explanation and another great video. Thank you.
Mine goes up to 11.
It’s the radio tuner!
Thank you Mentour Pilot, I'm sure this helped some people to understand the trim, but since I know that all this info doesn't fit into everyone's head I have a message for them. Let's say we are driving a car in the highway and of course we want it to go straight. But the roads they are not flat and leveled because the water from the rain needs to drain away from the road surface. So, the roads could be either higher in the middle and lower on the sides or lower on one side and higher on the other. The front wheels of the vehicle are trying to turn toward the lower side. In other words the car does not want to go straight but it pulls slightly to that direction. To compensate for that, you apply a little pressure on the steering wheel toward the opposite direction and you hold it there and this way you are forcing the car to go straight and not toward the curb, the ditch. What you just did is you "trimmed" the wheels of the vehicle. In the same manner, the pilots adjust the aircraft's aerodynamic controls in a way to compensate for the deviation from their route due to winds and other weather conditions that push the aircraft left or right or up and down. I will not provide any further technical details nor what the aircraft systems do to help out the pilots to lighten their workload because that's the job of the Mentour Pilot.
Excellent explanation. Thank you Mentour.
Haven’t you done a video about this already!?🤷🏻♂️☺️
@Tyler Sinden ah, okey! It’s wasn’t any complaints tho, just a thought 😁
@Tyler Sinden Wasn’t the other video specifically about the MCAS failure on the MAX?
@@TheGbelcher 3 years ago he has a video titled "what is that spinning thing" not specifically about mcas
@Jason Bowman The children that run RUclips probably didn’t like it either.
He’s milking us like cows 🤡🤡🤡
You also loose alot of finess from the horizontal stab when you need to use a big elevator angle. That's why the first way to fix the trim is to move fuel forward and backward to keep a neutral elevator angle. That's also why it's more efficient to keep the entire profile streamlined by pivoting the entire wing.
You cant move fuel forward and backwards in a 737NG tho😉
lose
Thank you for your explanation of the question I asked some time ago
Regards Jos van Hertrooij
This Channel is much better then discovery channel, which i loved to see when i was a teenager, incredebel welll spoked, incredebel good to explaine, if i understand all this then anyone does too, RESPECT to you sir. And thank you so much for all this videoes. Mr ioan from Denmark
You mentioned quite a few times about the spinning things getting jammed and how to manually turn them but how often does that happen? Have you personally ever encountered that situation and wondering whether at that moment of urgency (noticing the failure) is it really possible to focus on manually turning them?
Dang! I shoulda watched this one first! I'd think the trim in submarines is similar. Thank you. You explained this perfectly.
Petter, would you please explain/comment on Alaska 261 that lost control and crashed in the Pacific in Jan 2000 due to a failed stabilizer.
How did you post this 58 minutes ago when the video was only posted 2 minutes ago??
@@tubby1 we patreon’s get to se the video a little bit earlier!
The nut broke because it had not been properly lubricated. In part this also happened because the flight crew went outside of SOP and tried to fix the stab trim by activating both trim motors at the same time.
@@tubby1 I have a HOT Tub Time Machine ... works best in Winter
I'd have thought in the case of runaway trim instead of having to hold the wheel with your hand there could be say a small metal bar you could slide into the wheel to physically stop it moving. Of course, I've no idea how common a runaway trim situation is so it may not be financially feasible to build this into the trim-wheel mechanism.
As always excellent video Petter and beautifully explained, I love these type of explanation videos you do.
Great video as always, now I'm going to be checking out all the pilots biceps before take off to make sure they did not skip arms day, LOL.
With the elec motor they skip arms day as much as they can😆😉
Love the videos! I chuckle every time you say stab - ilizer 🔪
Stab-ilizer is established 🗡
😂😂😂
Just reiterates further why pilots don't want people up and moving all around while during takeoff I guess, they'd have to keep constantly readjusting trim if that were the case, and they got enough things to worry about at that time already. This is such a good channel even for people that aren't pilots, that just enjoy learning like I do
Thank you for all the information!
I almost feel like I can fly a 737!
Regards from the UK...
Thank you. I love aviation. I never understood what these things were.
Awesome vid! I have long wondered, but been to shy to ask! I feel I understand so much more now. I have long wondered about the MCAS failure on MAX, and now get much more how integral the jack screw stabilizer movement is to flying the plane. I need to AMP up my home sim and try to learn more. (Trim input on my hangglider is all manual :-) )
I did wonder what they were there for during the “could a passenger be talked through landing a 747” video. In honesty in that scenario even in a flight simulator I’d be so tense and anxious that when they first span around in my presence I wouldn’t have been expecting it and almost jumped out of my skin.
That being said, I’m surprised that my guess on their function wasn’t actually that far off as I figured they probably were some kind of manual control just in case the computer took inspiration from my PC at home and just stopped working for no apparent reason. Which, given my closest experience to piloting is when I stole a fighter jet in one of the Grand Theft Auto games, wasn’t a bad guess.
Glad I watched this video. I've been watching a lot of aviation videos (on this channel and others) and kept hearing the term "trim" but didn't understand what it was or what it did. I had a basic understanding of elevators, rutter, etc...but just not the trim. Thank you for such a clear (and detailed) explanation!
Are those port & starboard running lights on the sofa?
Indeed 😉
Liked before watching video. Thats the story delivery of this guy!
An accident with Alaska Airlines happened because of a vertical trim failure due to maintenance scheduling issues. The airplane had not been serviced properly and the jack-screw was not properly lubricated. It then got stripped and came out of the nut that connected it to the horizontal stabilizer and the pilots lost control of the pitch of the aircraft. Not a good thing.
Exactly what I was thinking when watching this.
and now I can't hear "jackscrew" without cringing
Enjoy your work fella. Thanks again.
Thank you!
"....... Seems as the 737MAX planes are coming back, I thought I'd discuss this......"
- MP
@Jim Mork If you prefer something more dangerous than the MAX or the amusement park, I can suggest driving a car.
@Jim Mork There have been countless examples of cars crashing into mountains or plunging into water. Drowning is never a pleasant way to die. If a plane crashes into water usually people die quick and painless.
@Jim Mork no intention to argue about that,but you can google for the toyota trhottlegate case.a bug in the code of some toyota models who make the car suddenly go full power.
not a faulty sensor or similar,a real program bug that make the car go full throttle.
@Jim Mork there was quality control staff who got fired because they found they were using substandard parts,making them fit by drill and hammer,specially the wing forks,those who later needed replacement and much more parts.there is no regulators actually,boeing certifies itself their own airplanes and the regulator just accept the incoming documentation,without test or verify nothing.thats why they are not more the standard for the rest of the world like before.there are documentarys here on YT,and they seem legit.
The toyota case,it seems the code was a pretty nasty mess,plagued with patches over patches never cleaned.finally they accept to pay to the US goverment on the condition to not look further.
dont know who is worse.
Excellent explanation. I am a flight dispatcher. I never really understood stab trim other than it being a number we work out on the trim chart, but now it makes sense.
I always thought they were fidget spinners for the pilots to play with when they get bored.
Seriously though, trim is equally important for RC cars. When you've got a toy car going 60 miles an hour with less than half an inch of ground clearance, the car is capable of veering off-course and smashing into a curb (or someone's ankle -- or face, if the car catches the air and turns into a kite -- yes that can actually happen) before you even have time to realize something is going wrong. So you have to trim the steering accurately enough that you can punch the throttle and accelerate all the way to top speed with minimal steering input, or else the car will be too unstable to actually drive.
In your RC car example, is it not rather like a deadzone setting, more than a trim ? (you make the deadzone bigger, so that little impulses on the stick are not registered, where a trim acts as a force, and moves the center of an axe in one direction, so that if you release your hand or thumb from the remote, it centers on a value different than the original untrimmed zero value, in your case the RC car would then have a tendency to turn, as a real car with bad wheels geometry). If it is a trim in the case of RC cars, is it because the small car has an issue of wheels geometry, or because of outside factors ? (such as wind, or the track geometry)
Incredible how the trim wheels are connected to the stabilizers all the way along the aircraft!
Most wires go way back. The motor in the floor behind pilots seat controls movement in the tail. Hydraulics reach all the way back to operate systems plus landing gear. There are2 actuator pumps which activate to pump hydraulic fluid to systems.
I'm just hitting every video in my recommended using "Open in New Tab" to wish everyone a happy and safe end to 2020! Love all of you (even if I've argued with you). Be safe, be well, know you're loved, let's work our asses off to make 2021 a little less... grim. No matter your deity (if any), we are humans... let's stop acting like it and actually come together for a better world.
The same to you, Jeremy. Let's see if we can make 2021 better. Since 1200 BC we've had more than 250 epidemics and we're still here. This latest virus won't take us out either. It WILL take out the elderly and those with a compromised immune system.
I worked for an airline that used to build their own B727 cockpit procedures simulators. The simulators had no motion as it was only for familiarizing new pilots with cockpit procedures and switch locations. The guys who made the simulators used cake pans painted black with white stripes for the pitch trim wheels. As a result all the pilots and mechanics called them pie pans.
Almost twenty two minute video went by in a flash. Always interesting and informative content. Thank you.
@Hello Stephen how are you doing?
Not the same without the doggies in the background.
@Jim Mork the black one is just as cute.
@Jim Mork oh I see.
Normally they were always busy sleeping though😁. Bored with all the airplane stuff!
@Jim Mork as soon as he stops speaking they are straight to the door wanting exercise.
Great video and explanation. I nothing about flying and still found this interesting and easily digestible.
He said "with me so far"
Me: still here but not understanding anything 😂🤣
Thanks for the very informative n intresting vdo. Due to Covid my air travel has completely stopped. But still curious about planes I started watching vdo's about planes and got attracted to air crash investigation's, but didn't knew the technical details. This video cleared me about trimming the aircraft. subscribed!
I don't know what the spinny things are, but if I hear my pilot refer to them as "spinny things" I get really nervous.
Lol, imagine the “could a passenger be talked through landing a 747” scenario and when those spinney things first moved, them managing to freak the poor unsuspecting bastard out. I could take a pilot dumbing things down to my level.
Clear skies and happy landings, and happy holidays - whichever one you celebrate.
A lovely video, as always. Is this in response to the Max entering service again? Or are you at liberty to explain why you are revisiting this subject? (Not that you really need much reason. The trim system is surprisingly fascinating.)
No, it has nothing to do with the MAX
It is a weird video. There is obviously no mention about Max as if the pilots were not allowed to talk about it anymore. It sounds and looks like some Boeing promo video. The airlines using them are probably counting on that people will not be asking about the aircraft type after lockdowns are finally lifted being happy to be able to fly somewhere at all. But I think that the whole era of cheap flying in cramped economy class represented by obsolete 737 is over. People will be willing to pay more for their safety and comfort and the bet on Max entering the service again as if there was no pandemic is wrong.
@@resortsman what is with the amount of dumb conspiracies under this video
Very well explained..even a layman like me understood and enjoyed it..Thank you!
Glad to hear that!!
this sounds complicated and arcane, and i now realize how much of a novelty fly-by-wire systems can be
In basic flying school, the trim is used to maintain airspeed. When the aircraft is properly trimmed, the thrust setting decides the aircraft climb or descent rate and the nose angle changes to maintain the same airspeed. So Pitch, power and trim.
The fact that they reuse the same warning sounds for different things (takeoff configuration and cabin altitude) really bothers me - there's no reason these days that they couldn't have a distinct sound. Confusion about the meaning of that sound was a contributing factor in the crash of Helios flight 522.
While this is true. Typically the alarms that are shared can either only be set off in the air or on the ground. I.E. if youre in the air it can only be one of the two. And if youre on the ground it can only be the other.
@@zachfield5336 Can actually be both in the air, but very rarely🙃
@@speedbird9313 If your takeoff config warning is going off in air. youve already fucked something up.
@@zachfield5336 Now THAT is very true😆🤭
@@zachfield5336 Helios 522 thought they had a takeoff config warning
great video Capt Petter...wish you and your family a Happy Merry Christmas
Kerbal Space program (which also does planes) is pretty good for learning about the center of mass and gravity and how to use and not use them.
Messing this up is usually the most common beginner mistake.
Scott Manleys old Beginners Guide to Aircraft Aerodynamics saved a lot of kerbal lifes for me. and at the same time gives a great and visual idea about how it actually works (simplified).
I changed a trim motor in the floor and a t tail elevator motor up in the tail a narrow space they call hell hole. I didn't understand exactly what it did but 2 years later when I took up flying I learned and now reiterated more significantly its purpose.
Super film 👍👍🙂🙂
I finally know what those turning wheels in the airplane cabin are for. I've always been curious what purpose they were placed there for. Thank you very much for a good technical lecture.
Greetings from Poland
Supposing many aircraft in a holding pattern at a busy international airport. What is the standard response when communication from ATC is completely cut?
PHONES HT EORKIN MAN OR CHANGE TO SPRINK OR MCI FO RLOND DIOSTANSE SAVEINGES,
@Peter Mortensen hello mine frende! are yiue rekated ti Torre Migewbse who used t bee ts TC electrices? THNKES YUE AD TUBBMERS UPPSERESES!
Beautifully explained.
If all trim and control system fails and stucks, is it possible to fly or land or turn the plane if full of obeying passengers (in theory) just by ordering them to go to the left/right side of the plane or if everyone moves/runs to the front/back of the plane or somewhere inbetween assuming they can go to the proper spot perfectly and instantly? :) Can they mess up the landing by running around and jumping in sync, and if yes then how much? :)
Yes I think you can. - Though it would be far more for elevator trim than roll trim because of the shape of the cabin..
The big problem though is that passenger control response time tends to be pretty slow. (which then tends to lead to things like uncontrollable feedback oscillation..)
As a simulator tech in the Air Force, I was assigned to a KC-135 (Boeing 707) simulator. During some of the practice "missions", the instructor pilot would cause the trim wheel to run away. Although crude, the solution to that situation was to grab the wheel and prevent it from spinning. That wheel is turning with a fair amount of torque and the co-pilot would have to stop it with his bare hands.
Great information in this video. Explained clearly. Keep it up
I always wondered about the spinning wheels as well. Glad you explained this. I did not know the complete stabilizer moved as well. I thought it was just the elevator. Was a runaway jackscrew the reason for the Max crashes? Just asking.
1 There is not the elevator, is the horizontal stabilizer, not the same.
2 the max crashes happened beacause a software error in the Maneouvering Control Argumentation System.
@@Dani-pl8cw MCAS works by moving the jackscrew so, technically, they were caused by a runaway stabilizer
@@aarondynamics1311 yes, but is not a runaway because they work, but not in the right way
@mentour pilot
@@Dani-pl8cw I never said they were the same.
I always wondered if there were any cases of a pilot getting his tie or belt stuck in the wheels.... oops
Seems like weight and balance is more complicated on airlines without assigned seating?
Well if there's no assigned seating, they will move people if there's not enough people evenly distributed. Even on flights where they do have assigned seating, I once got a change of seat at the gate because there weren't enough people sitting in the back (the flight had only like 20 people in it)
This could be a whole series!!
How much effect does passenger seating have on the balance?
How about cargo? How do you know the exact weight of all of that? (I imagine cargo is weighted and distributed accordingly)
Who guarantees that the cargo is properly placed and distributed on the cargo hold?
Like I mentioned in the video, we know when we get the load sheet. That’s when we set the stab-trim
Military have loadmasters to help balance cargo. Flight engineers to help calculate the fuel usage. Modern planes eliminate flight engineer & have many automated systems to compensate.
@@sharoncassell9358 I didn't ask about fuel. The flight crew calculates that.
Commercial aviation is not a military operation, with abundance of money to waste.
🤔 So you answered a question that wasn't asked.
Not a Pilot, not interested in being one, watched the whole video........I love it when people know there shit !, Subscribed !