After flying 34 years with the airlines, including five years with Turbo Props and various narrow body jets, I have yet to hear an instructor explain these procedures as well as you have…. I have enjoyed each and every video.
I figured that I better add a quick comment. Vmc definitions focus on rudder authority, not aileron authority, but they’re really two sides of the same coin. I didn’t really explain that in the video…
Tough to do with MS Flight Sim, for sure. My animation skills end at PowerPoint, which means I might have frozen the screen a few times and applied clipart arrows to explain the forces a bit. Please don't take this as criticism. I like the talking head feature of your channel, fwiw. Good call.
As a retired Australian flight instructor with multiple twin ratings including Cessna 300 and 400 series i am amazed at how many VMCa accidents happen in the US. I saw your reference to not empasising the importance of rudder but I feel I should make some points. So for the inexperienced pilot who read this..... The problem with an engine failure in a twin is asymetric thrust. This thrust produces yaw. You correct yaw with rudder, not ailerons! The C310 has a VMCa about 80kts. It has a best rate of climb SE of 106kts and a best angle of climb of 95kts. You should be NO WHERE NEAR VMCa! The way to avoid VMCa is with AIRSPEED! Not ailerons! Not angle of bank!. The aircraft WILL be sideslipping because it is producing asymetric thust! What is important is holding a heading and preventing un-wanted yaw. It is correct that if you get below VMCa you MUST reduce power on the good engine. Once power is reduced you will regain rudder authority. Nose attitude controls air speed so you must lower the nose and regain airspeed to 95 kts at least and re-apply power. RUDDER prevents yaw not ailerons. The 5 degree angle of bank is not to save you from VMCa, it is to improve climb performance once you are in control and have achievedd 106kts. It is obvious to me that VMCa is NOT well understood or well taught in the US, if it was there would not be so many fatalities because of this. My first twin endorsment included a VMCa roll over demonstration with the appropriate recovery method. This was obviously done at altitude. I can assure you this demonstration remained firmly fixed in my mind. I suggest all twin pilot go out with an instructor and do this exercise if you have not already done so. IF you get to VMCa, you are going down! You must remain in control by reducing power and lower the nose to gain AIRSPEED! In a twin, AIRSPEED is KING! If you are anywhere near VMCa with an engine out, you are "behind the power curve", you will NOT be climbing, you will NOT be maintaing height, you WILL be going down! Look for the blue line speed and fly it REGARDLESS! Holding it straight, identifying, feathering, cleaning up the aircraft are all priorities before worrying about 5 degrees angle of bank!
I think I see your point. The 5* angle of bank toward the good engine serves to balance the plane so it will fly essentially straight through the air. The ailerons will however, create a starboard yaw that must be countered with slight rudder.
@@coreyandnathanielchartier3749 There is no such thing as "slight rudder" in a twin with one engine out unless you have reduce power on the good engine, say in a descent or approach. With power on strong rudder pressure is needed, this can be trimmed out of course once you are stabalised in the cruise but beware the effect when power is reduced. With one engine feathered and the other windmilling at idle power the aircraft will yaw toward the "good" engine. Practice and practice again until you understand the forces involved. Rudder and airspeed are the most important, 5 degrees bank will improve performance once you are stable.
Excellent video and explanation. Only issue I have is about Vmc having to do with ailerons countering roll when it's actually rudder, but you did mention this somewhere in the comments. Being from the area, this crash hit close to home. And being a multi-turbine instructor, I am going to try incorporating this video into our single-engine courses. Vmc or Die is a perfect title.
Nice Video. I fly a C414A and can confirm what you said. I've experienced two engine failures (one in a C340 other in a 1975 C414) and there is little performance there. I do a lot of low alt engine failure practice on X-Plane and agree it's closer to reality. Nice job!!
Jesús, that’s allot to absorb and this is clearly why we see so many twins with engine failure close to the ground involved in fatal accidents. Probably best to stick with a high performance single for private pilots.
SO well done. I knew asymmetric thrust was bad, but it's really BAD in a conventional twin. Stuff I never knew. One word - Skymaster. Wish I could afford to spin two props.
Really good video. I do think they are safer for the pilot with the right mindset and training however. I fly a 3 engine big jets as a captain and I own a baron, I have to remember that if I lose one in the baron sometimes straight ahead is the best option, and I need to think about it more like a power loss in a single. I separate the 2 in my mind. It is not gonna fly out like a jet, and V1 is basically blue line in most situation. I tried this out hot and have in MSFS out of Santa Fe after watching your last video, and it’s a bitch. Once or twice I just ended up with an off airport landing. I took off out of Oshkosh yesterday in real life eastbound at max gross weight, and briefed that if we couldn’t land straight ahead and it wouldn’t fly I was gonna nurse it over the houses into the lake just off the end. I also agree about xplane having a better flight model and handling more realistically with an engine out. If you ever need help with the videos let me know. I think your channel is gonna go far.
Thanks for that! Those Barons are nice, but if the numbers I’ve seen for single engine climb are right, it shouldn’t climb out of a 6,000’ airport on a warm day near max gross. I did it out of Centennial airport in Colorado a while back on MSFS (about the same altitude) and got the same results as you (I also had it at max gross). I kind of think that MSFS may have the performance on it turned up a bit. Still, great plane!
Ive watched a few great pilots flyibg twins get in front of the power curve when loosing an engine on takeoff. 1) pick longer runway you can get to 10 knots faster on rotate. Closer to blue line speeds, Never rotate early. 2) dont use flaps, one less step in procedure, choose longer runway. 3) gear up 5 ft above ground. Thats 2 steps left out of procedure during engine out. Removed flaps & gear up steps immediantly. Plus less drag. 4) throttle, props & mixture are most likely set duribg take out so less to think about in emergency. All are full forward already. 5) pitch for blue line, raise dead on engine 5 degrees, split the ball using rudder. 6) then identify, verify by pullibg throttle on dead engine to idle, feather dead engine & pull its mixture off. Lastly turn off fuel pump, adjust crossfeed fuel. ⛽️ Either land off field straight ahead best option even gear up & survive landing.
VMC roll is caused by P-factor as much as it is asymmetric thrust. P-factor is why it's worse to lose the left engine than the right engine. The down-going propeller blade takes a bigger bite of the air and therefore, pulls harder than the up-going blade..
Yes, P-factor plays a roll as well. I was mainly focused on the misunderstanding about bank into the inoperative engine, but critical engine is obviously an important concept in many light twins.
@@flyingformoney777Plus, P-factor gets worse as you raise the nose struggling to gain altitude. And, the use of ailerons will cause one wingtip to stall before the other, causing the plane to roll in the opposite direction. Your natural reaction is to add more aileron when that wingtip drops. When my instructor showed me a spin to the left in a Cessna 150, my brain immediately wanted to go to the right side of the plane. It’s not quite as bad when sitting in a chair in front of a computer.. 😎
Very well done…. I’ve have been fortunate to fly/own a Aerostar 700. With one engine (loss of one), it climbs out at 660 ft. But, you can’t be stupid with overconfidence.
I have to admit…. They go through the fuel…. While in Top of climb is 80GPH and when reaching top and on the step at around FL 30.. 40GPH @ 65% power. Insurance is $11,700 a year.. Annual is $15,000 +/-. Hanger is 18,000 a year…. Sure makes Alaska airlines sound cheap…. Other than landing at the closest airport possible. Fastest I e ever had her was 435 MPH heading from SEA to CGO with one very favorable tailwind…. And full power to see what she could do.. 😉
I have several objections with the concepts as explained in this video. Here a few of the most important iones. The ball 1/2 width off center is not "uncoordinated flight". Coordinated flight means zero sideslip angle. When there is no net lateral force, coordinated flight is equivalent to the apparent gravity vector being perpendicular to the wings (which is what the ball actually measures). But that's not the situation when you have asymmetric thrust. Certainly, when you have asymmetric thrust you want to counter the thrust yawing moment with rudder. However, the way the rudder applies yaw moment is through a lateral force on the fin which creates an unbalanced lateral force. So what happens next? Perhaps it's easier with an example. Say that the right engine fails. Initially you have an unbalanced yaw moment to the right that you will counteract with left rudder. The left yaw moment achieved by the rudder is via a lateral force to the right on the fin. Because of that unbalanced lateral force, the plane will start to drift to the right/ Because now the wind hits the fin a bit from the right, that will tend to create a left force which in fact will be felt as a reduction of the right force previously mentioned, which in turn reduces the left yawing moment initially achieved with the application of left rudder. So you are not fully cancelling the right yaw anymore. You will need to add more rudder. If you were going slow and you were already applying all the rudder you had, too bad, you don't have more rudder to add, you just lost control of your plane. So is there a way to cancel the right force on the rudder so we avoid the sideslip and the need to add even more rudder? Yes: Bank to the left enough so as the left horizontal component of the lift vector equals and cancels the right force on the fin. In this way, you can keep zero sideslip and a zero net yaw moment with the original rudder input. THIS IS WHY VMC IS LESS WHEN YOU KEEP A BANK TO THE GOOD ENGINE. YOU NEED LESS RUDDER TO ZERO THE THRUST'S ASYMMETRIC YAWING MOMENT. VMC DOESN'T HAPPEN WHEN YOU RUN OUT OF AILERONS TO KEEP THE WINGS LEVEL. IT HAPPENS WHEN YOU RUN OUT OF RUDDER TO ZERO OUT THE YAW MOMENT and your plane yaws and rolls (as a result of the yaw) out of control. Note that if you bank the plane to cancel the later forces, you will be flying in a bank but with net zero lateral force and with zero sideslip. THIS IS THE REAL COORDINATED FLIGHT. Yet, the ball will "fall" a bit towards the lower wing because you are banking but not turning. But if you pout a yarn in the middle of the windshield, the yarn will be completely centered. This applies to all airplanes, prop or jets. There are a few differences between prop an jet, yes, but this is not one of them. This is just rudder compensating the thrust's yaw moment and bank compensating the rudder's unbalanced lateral force. The source of thrust is irrelevant. The differences between jet and prop are: a) In a jet you don't need to maintain aileron input to maintain this status. You are in coordinated flight (even if the ball tells otherwise) and the lift is symmetrical. In a twin prop the working propeller will be blowing higher speed air over its wing which will then generate more lift so you will need to maintain aileron towards the good engine to keep the bank constant. b) Other effects of propellers (like torque and p-factor) will make that you will need more rudder and aileron to compensate the loss of the left engine than the loss of the left engine. Those effects don't exist in a jet. c) Most jets are required and designed to have an engine failure during the take-off roll at about V1 (which is typically before Vr and before lift-off) and still be able to maintain directional control on the ground, accelerate to Vr, lift off and accelerate to V2 which is the minimum speed you should keep in the climb after losing an engine. V2 is typically much larger than V1. The rudder is design to maintain directional control at V1 and, because the effectiveness of the rudder goes with the square of the airspeed, by the time you reach V2 you have plenty of rudder authority so the bank technique is not really critical. V2 is well above Vmc. In a prop twin, Vmc is Vmc so if you are flying at Vmc you have ero margin, you NEED that bank to maintain control, and the blue line (the minimum speed you should keep when climbing on a single engine) is typically not much higher, so you have margin but not much, so the bank technique is still critical. Finally, I don't know where you got that wrong notion that Vmc changes with weight. Unlike the stall speed, it doesn't. And the reason why one does and the other doesn't is easy. Lift counteracts weight, and weight depends on weight. Rudder counteracts thrust yaw, and thrust and it's lever arm do not depend on weight. What does depend on weight is how much bank you need to keep the zero sideslip condition. The heavier the plane the larger the lift so you need a smaller bank to achieve the same horizontal component of the lift.
@@yamashill ... Higher Vmc compared to what? Yes, if you allow more bank angle, your Vmc will go down to some degree. But your stall speed will go up. Physics and aerodynamics doesn't care about policy. But would you like an airplane manual to say that the Vmc of the plane is 70 knots and that it requires 30 degrees of bank for straight coordinated flight?
@abd12: In all honesty, I made this video for people just like you, who have a TON of misconceptions about this stuff. There is a persistent yaw with ball out of center, plain and simple. The 5-degree bank is there to maintain heading because of that yaw. It has NOTHING to do with “canceling” yaw (if you canceled yaw, there would be no ball deflection). And though jets don’t have p-factor per se, they do have rotational effects very similar. With the exception of the rare counter rotating engine, all wing mounted twins have a critical engine for this reason. To the degree any of your objections have merit, it comes down to definitional differences. What is meant by “coordinated?” If you are referring to orientation with the slipstream, you are at least partially correct. If you are referring to yaw, you absolutely are not. And Vmc is 100% dependent on weight. Do not mistake published Vmc speed (which is established based on the worst case scenario of light weight) with the ACTUAL Vmc speed (the speed at which rudder/aileron authority is no longer sufficient to counter yaw induced rotational forces).
@@flyingformoney777 ... You are saying things but you are not explaining why. I did explain why. "There is a persistent yaw with ball out of center, plain and simple" Why? I claim that not. And I explained why. But here it is again and expanded. The ball is just a ball in an arched tube. Has the same function than a highly dampened pendulum. It will just point in the direction of the apparent acceleration (one component of it anyway). If the airplane is parked in an include ramp, the ball will be off-center and there is no yaw (or, more correctly, sideslip angle, since "saying "there is yaw" is like saying "there is pitch"). You have vertical component of lift cancelling weight, rudder yaw moment cancelling thrust asymmetry's yaw moment, lateral component of lift cancelling lateral force on rudder/fin, and the plane is in equilibrium of both forces and moments, flaying straight, and banked. There needs to be no sideslip (the yarn on the outside of the widescreen would be perfectly centered) and the ball is off center. Explain what of that is wrong and why. "To the degree any of your objections have merit, it comes down to definitional differences. What is meant by “coordinated?” If you are referring to orientation with the slipstream, you are at least partially correct. If you are referring to yaw, you absolutely are not." Please define what you mean with "yaw" and how does the ball measure it. I try to avoid "yaw" because it is confusing. Yaw can be just an axis of rotation, and an angular position (or displacement) about that axis relative to a zero reference. The movement about this axis is normally called "yaw rate" (what the stick of the stick-and-ball instrument measures). Similar with pitch and pitch rate. The action of yawing is the action of changing the yaw angle, like pitching (up or down) is the action of changing the pitch angle. Sideslip, on the other hand is the angle of the plane relative to the slipstream, like angle of attack, but lateral. The relationship between yaw and sideslip angle is the same than between pitch and angle of attack. So what do you mean with "yaw"? Sideslip or lateral angular velocity (i.e. heading rate)? Or something else? In any case, what you want to do is to keep the plane flying parallel to the airstream to minimize drag and keep rudder authority. So yes, I care about sideslip angle being zero, which in an asymmetric flight condition means that the ball must not be centered. "And Vmc is 100% dependent on weight. Do not mistake published Vmc speed (which is established based on the worst case scenario of light weight) with the ACTUAL Vmc speed (the speed at which rudder/aileron authority is no longer sufficient to counter yaw induced rotational forces)." Again, no. Vmc is the speed at which you run out of rudder authority, not aileron authority, and that doesn't depend on speed. The only reason why you need to keep aileron input at all in a prop plane (other than torque and p-factor) in an one-engine-out condition is because the good engine is blowing air over a part of the wing increasing that wing's lift, but the failed engine is not. But in a jet (or a twin prop like the Avanti), you don't need any aileron input to keep the plane form rolling one way or the other (assuming you are using rudder to cancel the asymmetric thrust's yaw moment) so you are never going to run out of aileron... but you still have a Vmc. In my opinion, you are the one that has many misconceptions, not me. And I am explaining why. But in any case I don't want this to be a "who is right / who is wrong" pissing contest. If I am wrong I want to understand it. Understand it, not just believe it. That is why I am asking you to explain why what I say is wrong and why what you say is right. And I am offering the same in exchange.
Your attention to detail in explaining the effects of asymmetric thrust as amazing. I never thought of the trained use of rudder, and how it is adversarial in this case. The Santa Fe accident scared me (I fly a 310R), particularly because the pilot must have been a great stick&rudder, but you may have a point. That said, it was a turbo, so would it not have had more climb performance at 9000 feet density altitude, even with average technique. The NTSB will report if the failed side was feathered, and if that remaining turbo was operating.
I would say that an extra engine DOES make you safer for the most part. There are some caveats though that can get you in trouble, especially at slower speed, i.e. taking off or landing. Here you can get in trouble for sure if you are not ready or proficient.
Two engines doubles your odds of an engine failure. So, for it to pay off, it needs to double your chances of avoiding a crash landing. There seem to be a lot of twin crashes so I am not so sure it really improves the odds.
The idea behind the twin and safety assumes that you are properly trained and have the experience to handle a twin engine, and complex (constant speed prop, retractable landing gear) aircraft. If properly trained the twin provides a safer flight. The buffalo and the "pusher pull you"cessna" are exceptions given their single engine performance.
Your bank angle analysis is ABSOLUTELY CORRECT! The Bank Into the failed engine is BS! The rudder AND airspeed is the savior of the failed engine situation. After 50 years and 20K flights hours, YOU finally are telling the truth about "coordinated flight" to survive an engine out situation! Good on you for properly explaining this life changing emergency!! Old ATP; Venice,FL
Just a great job in this video. Very comprehensive, never getting off topic. I've brought nine back with one feathered, and the advice here is spot on.
I received my multi-engine rating in a Piper Seneca with counter rotating props vmc was fairly minimal but while training with a Piper Navajo with turbo engines I had to demonstrate vmc and recover. Then my instructor feathered my left engine and did some air work and turning into the dead prop I had to make a landing with the left engine shutdown and making normal left turns in the pattern. All very stressful even with the instructor along. Think what it would be like IMC at night! I flew that Navajo many many hours and thank GOD I never had a engine failure. I do think counter rotating props do help a bit with the VMC problem but there is a Macho feeling out there with pilots. Trouble flying a twin one one engine? Then fly a single! I did saw a demo pilot flying a souped up Navajo do a left engine feather on take-off at 25 ft agl Ever see Bob Hoover fly his Aero Commander he was the VMC expert!!
Fascinating and yea I wouldn’t put myself in a twin that has a critical engine namely both have to be counter rotating, and secondly doesn’t have an auto feather Too much to worry about when things go south and very rapidly.
I've seen a 402 take off , lose one engine , then a few seconds later went into a Vmc roll.Confusion as to which engine died was chaotic as I was later told , the pilot brought the working engine to idle , recovered from the roll , landed straight ahead and wrecked the Airplane. The four occupants survived. A lot or recurrent training would have prevented this but at the end ,the passengers and pilot are still around. Great tutorial by the way ! thanks !
Excellent! Like John, below I am also a long time guy who is now spoiled because I fly jets. We don't even consider many of the points in this video because we have so much power available. Yes, the plane needs to be trimmed out for the engine out situation but we don't think twice about turning into the good engine. We just trim and fly. Not so when I flew the Dash8. Plenty of power on that plane BUT the massive props way out on the wing coupled with the massive rudder meant that you had to get that thing trimmed out right in order to relax on one engine. This is an exceptional video and should be required viewing annually by anyone who flies a light piston twin. Or, a fully loaded and heavy King Air, etc.
Man, so much trash talk in these comments! This video was good info. Every time I took off in a twin Cessna, I visualized flying it to an off airport landing after losing an engine. You have to be okay with that outcome if you fly light twins. If you *happen* to have enough airspeed / altitude to make it back, then great! The moment an engine fails, the insurance company owns it. Airspeed and keeping the ball centered is 1000x more important than anything else.
Absolutely brilliant explanations. Best I’ve read, seen, or heard; ever. Good lord brother, not all of us are so goddamn bright 😅 Could you talk a little slower for those of us on the average part of the spectrum?! Thank you for considering. What a treasure to find your channel. I’m watching this video another four times.
I think I see your point. The 5* angle of bank toward the good (let's say, Left) engine serves to balance the plane so it will fly essentially straight through the air. The ailerons will however, create a (add to the) starboard yaw that must be countered with slight rudder.
The rudder is deflected to counteract the yaw due to asymmetrical thrust. Nothing else. The deflected rudder gives the airplane a small sideways force. This is corrected by banking a few degrees into the good engine so the sideways component of Lift neutralizes the sideways force of the rudder. When flying correct on one engine the ailerons should be close to neutral. This is straight out of the Flight Crew Training Manual from Boeing. Don’t listen to this clown ‘Flying for Money’ The 5 degrees is not exactly, VMC air is determined by the certification with maximum 5 degrees bank into the good engine. Not necessarily 5 degrees. Could be 2 or 3.
Hello, very well done. The accident reports are still full of VMC accidents in twins. I too practice engine out procedures on FS2020 and XPlane 12. It does train your thinking enough that reacting to an engine failure becomes automatic after Sim practice. I sometimes look off to one side and then fail the engine to simulate it being a "surprise". No one should fly light twins without being ready to properly handle the airplane on one engine. Thanks.
Too many words. What was the failed engine short list? Trim Rudder towards the active engine, active engine wing down 5 degrees while using attitude to control speed and feathering the failed engine prop?
But which direction should you turn to make a quick return to the field, and should you even try? Immediate action items are a fine resource, but a little knowledge is never a bad thing.
@@flyingformoney777 I’m not criticizing the knowledge, understanding is vital, but I got completely confused as the video images seemed, to me, to be contradictory. This exact case was a famous Beechcraft Super King Air accident at Sydney Airport in 1980 killing 13 people. I’d like to understand if the situation was survivable. It all happens in such a short period of time, this is where reflexes are equally vital.
This is very well explained. Thank you!! These twin engine light planes seem to be death traps. Especially when the engine failure is on the problematic side. I understand that this is because the swirling prop wash degrades lift on the functional side. Would this be less of a problem with pusher props?
Glider pilot here, and I don't understand. Skip if you wish. So, does the typical twin generate significant adverse yaw from the aileron that is pointing down (which has a long moment arm - being out on the end of the wing)? If so, then banking into the dead engine increases the adverse yaw into the working engine, lessening the rudder input required to keep the aircraft from turning into the dead engine (because the dead engine side is cleaner)? It would seem there is little margin before a roll into the dead engine begins, even though that side is cleaner (from the wing's perspective, not the engine's). By modulating a relative slip into the working engine, with a little rudder into the working engine, one would have a hard time turning into the working engine. Of course, the airplane wants to turn into the dead engine.
The aileron doesn’t do much to a (compared to a glider) heavy twin. Most of the yaw is from asymmetric thrust. We don’t really consider aileron effects with regards to Vmc.
I flew the exact profile and executed as accurate the scenario reported on the 310 crash in X-Plane and was unable to recover 4 out of 5 times - funny thing is the successful flight was a result of leaning in to the good engine - I had very few options that I could notice in the struggle in that scenery and it was a handful from the get go, it made me feel so sorry for the PIC it was a horrible situation he could never be adequately trained for.
Hi ,at the 11.42 clip, I would like to ask, Could use a hobby model ,to demonstrate the maneuver your explaining? Or use vr to show us the maneuver? Thanks
There is a lot of good info here but I would quibble with your Vmc definition. It’s not necessarily the speed at which you run out of aileron. It’s the speed at which you out out of control in any axis. Depending on the bank angle you can run out of rudder first, which means you can’t maintain heading, or you can run out of aileron first, which means you can’t maintain bank. I have worked on the design of airplanes which encounter both conditions. Perhaps light twins, which are only aileron equipped, always run out of aileron first. The larger Biz jets tend to have spoilerons as well so they tend to be rudder limited. The Vmc demonstration for FAR 25, as described in AC25-7, allows up to 5 deg of bank into the good engine. This allows you do reduce the rudder deflection for a given speed, or reduce Vmc at full rudder, at the expense of higher aileron requirement. Why? Because you generate more proverse sideslip. This helps the directional axis but the resulting sideslip requires more aileron to keep the good engine down. That 5 deg bank will allow a substantial reduction in Vmc if you are not aileron limited. If you are roll limited then you can really use it.
I’ve not flown a twin. If I lost one engine at low airspeed, I’d reduce power and push the nose down to gain AS and aileron control, then bring RapM’s up. I think that if I was close to the ground and slow on takeoff, I’d dial in just as much power as the controls could handle. If this was not enough to climb, it would at least extend my glide and options.
Remember, the book number are performed by a qualified test pilot. So if your not proficient, don’t expect much. If you look like your loosing it in with engine failure in a light twin, close the throttle on the good engine and play like your a single ending ac with an engine failure. Takeoff in a twin with an engine failure is a tough senecio. But it you suffer an engine failure at altitude you stand a much better chance of a safe landing than in a single ac.
Thinking about aileron authority, slight sideways flight path, and vmc. I wonder if the large tip tanks contribute to a loss of aileron authority by disrupting airflow slightly over the aileron given a slightly sideways flight path? Not saying tip tanks caused the crash, but Im wondering if it might of contributed or if a wing clear of tip tanks would have performed slightly better?
That Was Really Great! Surely You're A CFI Or Lecturer At Some Aviation School. What's Your Take On Counter-Rotating Engines In The Same Situation? Thank You.
I think that, even though it may be true that banking into the dead engine can be done in very controlled circumstances, and knowing that pilots will always take the easy way out in a desperate situation, I don't tell people it can be done, unless they are going to die if they don't. Once you plant the seed of turning into the dead engine is ok, someone is going to get killed.
I used to read aviation consumer back in the 80's and they had an article about the Cessna 414 where the company hired the best pilot they could find to fly it on one engine and sure enough, it ended badly.
Expert analysis. Been a long time since I flew single pilot charter in my turbo twin Comanche. No one gets enough exposure to this kind of critical performance training.
You were soo close. Vmc is when "the Rudder" looses directional control and the plane yaws due to lower air speed & asymmetrically thrust from operating engine. One wouldnt want to use ailerons input during a stalled plane with yawing tendencies. A plane will not Spin when stalled if it does not yaw. One needs both stall & yaw to spin. Last but not least is in light twins its not just stall or a spin or a wing drop but VMC ROLL. This is when the twin pancakes, rolling inverted onto itself if below red line on airspeed indicator & rudder authority is lost.
Close, but not totally right. The wings do not stall in a Vmc roll, and aileron input is inevitable when a plane is flown with the ball half out of center. The roll part of Vmc roll is due to the rolling forces produced by asymmetric thrust overcoming control forces. Low speed loss of effectiveness of the rudder AND ailerons is what causes it.
@flyingformoney777 Notice what sim helps one feel what it's like better. You said X-Plane shown better simulation loss of engine. Any single engine plane do a lifelike wing drop when stalled or accelerated stall that you've found yet?
Further to my last comment, I would recommend that every pilot read 'Stick and Rudder' by Wolfgang Langweisse. This has been my flying bible for 30+years and although written in 1930 it is very relevant with all aircraft. A thorough understanding of flying the wing which, is all you are doing really will save a lot of lives and misery. Too many treat it like driving their car and an instructor or pilot that has that mindset will crash
You have lots of good information here, but there are also several inaccurate statements. A few of them are: Coordinated flight is possible and desirable in OEI flight, but it requires a yaw string to find it. And, more bank is not better, and most aircraft 3-4 degrees is the optimum bank angle, 5 degrees would be too much.
Thanks for the comment. It depends on what you consider “coordinated.” If you’re referring to aligning the slipstream with the aircraft, you are correct. If you are referring to the “sideways” feeling when the ball is out of center, you are not. I’m not sure what you mean by “most aircraft.” Optimal bank is highly dependent on many factors, so it does vary.
Nope. 8000 hours flying plus another 3000 in the sim as a check airman. You? You think that you can only turn towards the good engine after a failure? You might want to check around on that…
Do a booklet on these concepts as described by you with lots o illustrations please?! Third time watching and still taking notes! Bravo 🎉good sir. Thank you.
Very informative thanks. Off to X plane to try it out and see if I can do the 5 deg bank 1/2 ball. Should be a challenge. Find flying the Barron 58 a challenge anyway. 😅😅😅😅😅😅😅😅😅😅
Wow. Regardless of how right you might be, getting all this straight, after you’ve already lost 20 IQ points merely by sitting down in the left seat… and then having to overcome several seconds of startle factor… seems like a nearly insurmountable task. I’m wondering if it might be best to pull power on the good engine (probably psychologically impossible, never mind the time spent identifying the good engine) and fly into the crash.
Yes, sometimes we brief for that if we lose an engine below 400' AGL on takeoff. We pull back both throttles, so we're guaranteed to retard the good engine! No need to figure out which engine is the good one!
The aircraft rolls even with full, opposite aileron so yes, Vmc is partially about the loss of aileron authority. From an engineering standpoint the rudder more or less determines Vmc, but from a pilot’s standpoint uncontrollable roll is an aileron issue. Flip sides of the same coin.
I see. Nothing new for me. At low speeds (high AoA) It is better to use rudder pedals to roll. Because using ailerons may cause the assymetrical stall.
True if you are close to stall speed. Vmc isn’t a stall though. It’s the point where you run out of rudder to counter yaw, resulting in uncommanded roll. Rudder is important, but pilots are generally more attuned to the yoke/ailerons.
It's easy to defend my comment. Your statement that VMC is dependent on aileron authority is simply incorrect. A VMC roll is prevented by countering yaw into the dead engine using rudder, rather than with aileron input. Loss of rudder authority makes the increasing yaw and bank into the dead engine impossible to control even WITH aileron input. The same applies to attempting to prevent a stall/spin on the base to final turn. Aileron input to counter the increased bank toward the low wing simply increases the inside wing's AOA and brings it closer to a stall and the aircraft closer to an incipient or fully developed spin. Far more experienced pilots than I am have also criticized your video. JF ATP CFII MEI
I added a comment 30 minutes after I posted the video noting that Vmc speeds are established by rudder limits. I just did another video clarifying this. The definitions are obvious and so I assumed them in the first video. Vmc roll is different than a stall/spin. And to be clear, I never said that Vmc was dependent on aileron authority. I said that the rolling forces that occurred below Vmc were too significant to be overcome by the ailerons. And your last statement is pretty abstract. An empty appeal to an unnamed authority. Let your words stand for themselves.
I’m not sure your explanation of the effect of higher weights is correct. In steady state flight, inertia effects are zero (no acceleration). Rather, at higher weights, in a bank some of that weight is counteracting the force from the rudder defection, reducing total lateral load for the same rudder deflection, or looked at another way reducing required rudder defection for the same amount of side slip.
I was abstracting a bit on the weight part to keep it simple. More weight means more lift. At half ball, regardless of attitude, deflecting lift allows the aircraft to be oriented with the slipstream while using less rudder, like you said.
@@flyingformoney777 it's an oldie (1944) but goodie. I read it while taking flying lessons years ago and I thought at the time that if a person read and understood this book he could probably learn to fly after one or two lessons. here's a link, and no, I get no commission, but you could try look inside stuff. Good luck!
You need to explain more, because I’m not sure what you mean. The aircraft rolls uncontrollably and noses over. Try it on a flight sim (I wouldn’t suggest it in real life). The two look very similar. That’s why they call it a “Vmc spin.”
Yes, full power is one of the determining factors. Vmca is basically a measuring stick using a set criteria based on worst case scenario to gauge single engine handling and performance. That is failure of the critical engine and it is windmilling, maximum power set ( at sea level) on the live engine, either full rudder deflection or a nominated amount of rudder force e.g. pilot applying 150lbs force on the rudder pedal, 5 degrees bank towards the live engine, flaps set for take-off, landing gear retracted and aft Centre of Gravity. So if we change something to the criteria, it will change the Vmca speed. For example, a forward Centre of Gravity will give you more leverage from the rudder. More rudder authority, lower Vmca. Not having full travel of the rudder or cannot physically apply sufficient pedal force, higher Vmca! I had a student once who was quite petite. She went to the gym to build strength in her legs so she could control the aeroplane during her multi engine training. She's a 737 pilot now. Hope this helps.
FlyWire and Blancolirio both say twins spins are basically unrecoverable, so don't get in one. Agree? I think I do. Another video I watched made another point that uncoordinated flight with too great an angle of attack relative to the vertical stabilizer causes it to stall and that's what initiates a snap roll. Scary! ruclips.net/video/VcEg39NmxY4/видео.html&pp=ygURbWFydGluIHBhdWx5IHR3aW4%3D
A question. Blue line represents Vyse, but doesn't that assume that you have excess thrust available? In a situation where you can't maintain altitude single engine at Vyse, could an airspeed closer to minimum drag possibly allow you to maintain altitude, and how does that speed compare to Vyse?
It will be interesting to hear what @flyingformoney has to say. My very outdated two cents: Decades ago, my multi engine CFI and I took a 310Q to 9,500 feet during a warm summer’s day and we played around with it a bit. Vyse seemed to give us the best minimum descent rate. We didn’t fully shut down the critical engine, it was just providing zero thrust. 150 fpm descent was the best we could do and that was at Vyse.
You can obtain a better angle of climb at Vxse (sacrificing rate of climb), but the best “single engine glide ratio” (if you cannot climb at Vyse) is achieved by maintaining Vyse. You might be able to decrease the sink rate slightly at a lower speed, but drift down range will be less as well.
In a 310R, Vxse is 85 knots, and that's close to Vmc (80), but Vxse is actually lower if you're lighter than max gross (which is likely, and that Vmc is given for lowest weight). So that's not a good idea. The manufacturer defines Vsse, which is 92kts indicated in the 310, to keep you away from Vmc.
@@flyingformoney777 At any rate, we are probably talking about 100fpm at most, and I would bet it is probably less. In any scenario, flirting with Vmc is a bad idea. It's mostly a mental excercise in trying to understand how it all works in a situation where you have a thrust deficit at Vyse.
Ailerons have nothing to do with it RUDDER stop the yaw this will stop the roll Slight bank towards the live engine will help performance but always control with rudder first
I disagree with your assertion that Vmc is a function of weight. First, it's not that higher weights move less, its that higher weights accelerate more slowly, they still move.. As you approach Vmc, rotational speeds are zero anyway. Second, Vmc has to do with counteracting airframe rotation, so angular momentum is in play, not linear. This means that in any rotation the airplane responds to an angular moment of inertia, not plain mass. Third, Vmc is derived from rudder effectiveness vs off center thrust. Rudder effectiveness is a function of the rudder force AND the length of the rudder arm from the center of rotation in the yaw axis, ie the lever arm. So CG location plays a factor in Vmc; aft CG raises Vmc. Fourth, Vmc has to do with asymmetric thrust which produces (mostly) yaw, and is balanced by rudder. Vmc is about balancing these two forces, and specifically when they are no longer able to be balanced. As others have mentioned, ailerons are very secondary. Weight's most pronounced effect is reducing climb performance The greater rotational inertia (if any) will only slow the rate of turn entry or turn cessation. It will not change Vmc. i like that you mention reducing thrust on the good engine to maintain control. Many teach chopping power completely, not necessary if you react at the onset of Vmc. As you begin to lose rudder authority, reducing power on the good engine will reduce Vmc. Placarded Vmc is at full power, and of course you can always change that. This is important when trying to stretch a powered descent into terrain, you have more time to choose a spot if you fly with reduced power on the good engine. By reducing power, you can bring actual Vmc to below stall speed.
A few counterpoints. If you accelerate more slowly, over time you move less. I’m not entirely sure what your definition of “move” is, but mine is: lateral distance traveled per foot of forward distance. And “rotational speeds” (I assume you were referring here to yaw) do NOT go to zero at Vmc. Rotation is a result of asymmetric thrust, which (in a prop) does not change much as airspeed decreases. If you were referring to roll forces, at Vmc the ailerons and rudder are still producing rotational forces, but they are no longer enough to overcome rotational inertia. While we're at it, you mention inertia while simultaneously dismissing mass. What is inertia? It is “the sum of the product of mass.” I use the word “mass” because it is central to inertia, and something that everyone understands intuitively. This leads to your first complaint, that Vmc is not a function of weight. It is. Google “Vmc and weight.” If you won’t believe me, maybe you’ll believe all the other resources out there that draw the same conclusion: the lighter an aircraft is, the higher “actual” Vmc will be. I don’t disagree about Vmc being dependent on rudder authority, but the end result is uncontrollable roll, which is a function of the ailerons. As far as the pilot goes, Vmc is when roll can no longer be controlled, and flying with the ball “half out of center” decreases Vmc speeds because the ailerons are more effective while simultaneously less rudder is required. Ailerons are not “very secondary” to this equation. They, along with the rudder, are prime players.
@@flyingformoney777 Replying to your points in order: I used 'move' in a colloquial sense. The point there is that acceleration of a larger mass will result in a slower acceleration, BUT THAT DOES NOT INFER AN INCREASE OF Vmc. It only infers the rate of increase of the speed of the yaw and roll. And pay attention to the fact that while the higher mass accelerates more slowly, it will also decelerate more slowly. Stopping the roll or yaw will be more difficult. (This still only applies to rotational moment of inertia, the equivalent of mass in rotational dynamics. In aircraft, higher gross weights can mean weights near the CG, like passengers, or far from the CG, like tip tanks. It's not a one size fits all) Vmc is not about the rate of uncontrollable yaw, it is about the airspeed at which yaw becomes uncontrollable. And that happens independent of aircraft weight. 'As you approach Vmc, rotational speeds are zero anyway.' means that as airspeed slows and the aircraft approached Vmc, there is no uncontrollable yaw yet. You are still under control. You have not yet lost rudder authority and can still fly straight. At Vmc, you have not started to rotate about the yaw axis, that happens below Vmc. By definition. So yes, rotational speed is zero in a properly flown aircraft at Vmc. Nothing ever will "overcome rotational inertia". Rotational inertia is conserved, much like mass, unless you rearrange fuel or passengers. Since you usually don't have the time to do that, it is a constant. I don't think you understand what rotational inertia is. Much like linear inertia, it affects the acceleration of a mass. The mass always responds to a force. It is not overcome. And you get the definition of inertia wrong. In rotational dynamics, it is the sum of the products of the masses times their respective arm. And no, Vmc is (still) not a function of weight. Your internet reference is wrong. This is a great illustration of just because it's on the internet doesn't mean it's correct. If you are referring to this page: thebackseatpilot.com/pages/vmc look at the accompanying diagram. Note that it states that Vmc occurs when TxX (thrust times the lever arm of the engine from the CG) equals RxY (Rudder force times the lever arm of the rudder from the CG) This part is correct. Note that nowhere in this correct representation of Vmc is mass of the aircraft, or any part of the aircraft, in the equation. It is only the asymmetric thrust rotational force vs the rudder rotational force. Mass doesn't matter. What matters is when the rudder force available no longer is sufficient to offset the asymmetric thrust (and the added asymmetric drag of the windmilling propeller if not feathered) the aircraft becomes uncontrollable. Flying with the ball half out decreases drag, and therefore increases SE climb performance, it does not decrease Vmc. I'll leave it to the reader to look into that one further. Suffice to say moving the ball to any location does not affect rudder authority or asymmetric thrust, so Vmc remains the same. And where did you ever learn that at slow airspeeds ailerons are equally as important? Lastly, the published Vmc is derived from the most adverse (but still legal) conditions. It will never be higher, but it very well may be lower. I'm taking the time to go over this in detail (mind numbing as it may be) as it is important to keep low time twin pilots well informed, and hopefully prevent an accident.
@@midweekpowderhound "Move" means motion, and mass resists motion. Even in the colloquial sense. From CFR 23.151 (f.5): Vmc is established by: “The most unfavorable weight in the range of takeoff weights.” You link to one source and dismiss it, but there are many, many other sources out there that mirror this statement: “The most unfavorable weight of a multi-engine aircraft is when it is lightest…. Early certification of multi-engine aircraft did not specify the weight at which Vmc had to be determined. Therefore, many manufactures calculated Vmc at the heaviest weight resulting in the previously mentioned effects on Vmc to be reversed. In this case, actual Vmc matched published Vmc at the heaviest weight and increased as weight decreased.” I’m going to give you this point: the adverse effects of increased weight on performance are far more important than the slight reduction in Vmc that heavier aircraft demonstrate. But weight does, indeed, impact Vmc. For more: AC-8A: FLIGHT TEST GUIDE FOR CERTIFICATION OF PART 23 AIRPLANES: Page 60 and Section 48(c)(1) states that 'The critical loading for Vmc testing is generally minimum weight and maximum aft c.g.; however, each airplane design should be evaluated independently to be assured that tests are conducted under the critical loading conditions.' Likewise, flying with the ball half out of center decreases Vmc. You state that it has no effect on Vmc, only drag. CFR 25.149 (b): “VMC is the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine still inoperative and maintain straight flight with an angle of bank of not more than 5 degrees.” You need to understand that maintaining level flight with a 5-degree bank requires the ball to be half out of center. The rule of thumb is that for each degree reduction in bank (below 5-degrees) Vmc will increase by 3 knots. And I understand rotational inertia. Mass is still in the equation for determining it. Heck, you mentioned it in your own definition. And you’re misquoting me on this particular complaint. I was referring to mass as it relates to “5-degrees, ball out of center,” for which it is valid. I wasn’t referring to rotational inertia. I would LOVE for you to detail how ANY of this pedantic conversation is going to “save lives?” There are only a few main points to everything I said in the video (and yes, videos like these are reductionistic purposefully in order to drive home the main point and avoid intellectualist mire). Here, again, are the important takeaways: maintaining airspeed with a margin above Vmc is vital; Vmc varies and is highly dependent on maintaining ball half-out-of-center; if you cannot climb at Vxse or Vyse, accept it and find an off-field site. THAT is what will save lives, not our little pedantic argument here over definitional terms and the validity of sometimes contradictory source material.
@@flyingformoney777 I don't think higher weight reduces Vmca because of higher inertia. I believe higher weight gives lower Vmc than a lower weight when turning into the good engine (and conversely higher Vmc than a lower weight when turning into the dead engine) because the higher weight means that the wing has to generate more lift to maintain altitude, and therefore the horizontal component of the lift vector for a given angle of bank into the good engine is higher, lessening the need for rudder force to counteract the yaw produced by the good engine.
@@igclapp That is the official reason, higher lift. Unfortunately the official material implies that Vmc is only valid when in level flight with an offset bank. Lift increases in a turn if altitude is maintained (regardless of the direction of turn). The lift vector does not change relative to the slipstream if half-center ball is maintained. What happens to Vmc in a 20-degree bank into the failed engine? If it increases, then published Vmc would only be valid for turns into the good engine (and all POHs would have to caveat this point). This is clearly not the case. Aerodynamically speaking, the aircraft doesn’t care which direction it’s turning, only that the ball is half out of center. “Bank into the good engine” is simply the means to maintain heading. My “weight moves less” thing is an abstraction. You’re right, it’s not a perfect one, but it’s simple and the conversation becomes dizzying pretty quick.
It's an issue that always vexed me. However it would be very insttucted and more useful if you could provide with a simpler and graphical illustration of a stationary image with the forces at wotk under such contingency.
After flying 34 years with the airlines, including five years with Turbo Props and various narrow body jets, I have yet to hear an instructor explain these procedures as well as you have…. I have enjoyed each and every video.
Thanks! I appreciate that!
That has to be the best video narration I've ever seen on this matter! Excellent job!
I figured that I better add a quick comment. Vmc definitions focus on rudder authority, not aileron authority, but they’re really two sides of the same coin. I didn’t really explain that in the video…
Tough to do with MS Flight Sim, for sure. My animation skills end at PowerPoint, which means I might have frozen the screen a few times and applied clipart arrows to explain the forces a bit. Please don't take this as criticism. I like the talking head feature of your channel, fwiw. Good call.
Best 14 minutes on piston twin principles on YT…You out did yourself brother….Thanks🙏🏼✈
Thanks!
As a retired Australian flight instructor with multiple twin ratings including Cessna 300 and 400 series i am amazed at how many VMCa accidents happen in the US.
I saw your reference to not empasising the importance of rudder but I feel I should make some points.
So for the inexperienced pilot who read this.....
The problem with an engine failure in a twin is asymetric thrust.
This thrust produces yaw.
You correct yaw with rudder, not ailerons!
The C310 has a VMCa about 80kts. It has a best rate of climb SE of 106kts and a best angle of climb of 95kts.
You should be NO WHERE NEAR VMCa!
The way to avoid VMCa is with AIRSPEED!
Not ailerons!
Not angle of bank!.
The aircraft WILL be sideslipping because it is producing asymetric thust!
What is important is holding a heading and preventing un-wanted yaw.
It is correct that if you get below VMCa you MUST reduce power on the good engine.
Once power is reduced you will regain rudder authority.
Nose attitude controls air speed so you must lower the nose and regain airspeed to 95 kts at least and re-apply power.
RUDDER prevents yaw not ailerons.
The 5 degree angle of bank is not to save you from VMCa, it is to improve climb performance once you are in control and have achievedd 106kts.
It is obvious to me that VMCa is NOT well understood or well taught in the US, if it was there would not be so many fatalities because of this.
My first twin endorsment included a VMCa roll over demonstration with the appropriate recovery method. This was obviously done at altitude.
I can assure you this demonstration remained firmly fixed in my mind.
I suggest all twin pilot go out with an instructor and do this exercise if you have not already done so.
IF you get to VMCa, you are going down! You must remain in control by reducing power and lower the nose to gain AIRSPEED!
In a twin, AIRSPEED is KING!
If you are anywhere near VMCa with an engine out, you are "behind the power curve", you will NOT be climbing, you will NOT be maintaing height, you WILL be going down!
Look for the blue line speed and fly it REGARDLESS!
Holding it straight, identifying, feathering, cleaning up the aircraft are all priorities before worrying about 5 degrees angle of bank!
I think I see your point. The 5* angle of bank toward the good engine serves to balance the plane so it will fly essentially straight through the air. The ailerons will however, create a starboard yaw that must be countered with slight rudder.
@@coreyandnathanielchartier3749 There is no such thing as "slight rudder" in a twin with one engine out unless you have reduce power on the good engine, say in a descent or approach.
With power on strong rudder pressure is needed, this can be trimmed out of course once you are stabalised in the cruise but beware the effect when power is reduced.
With one engine feathered and the other windmilling at idle power the aircraft will yaw toward the "good" engine.
Practice and practice again until you understand the forces involved.
Rudder and airspeed are the most important, 5 degrees bank will improve performance once you are stable.
A must-read comment sir.
I couldnt say this better ! These are the exactly the esential points ! 👌👍aim this and stay.
The goal with one engine inoperative is zero sideslip. A yaw string on the nose was a teaching aid a local instructor used.
There’s a lot to consider when you’re 45 seconds into the air and the ground is coming up fast. Great video.
Excellent video and explanation. Only issue I have is about Vmc having to do with ailerons countering roll when it's actually rudder, but you did mention this somewhere in the comments. Being from the area, this crash hit close to home. And being a multi-turbine instructor, I am going to try incorporating this video into our single-engine courses. Vmc or Die is a perfect title.
Nice Video. I fly a C414A and can confirm what you said. I've experienced two engine failures (one in a C340 other in a 1975 C414) and there is little performance there. I do a lot of low alt engine failure practice on X-Plane and agree it's closer to reality. Nice job!!
Jesús, that’s allot to absorb and this is clearly why we see so many twins with engine failure close to the ground involved in fatal accidents. Probably best to stick with a high performance single for private pilots.
SO well done. I knew asymmetric thrust was bad, but it's really BAD in a conventional twin. Stuff I never knew. One word - Skymaster. Wish I could afford to spin two props.
Every twin owner should routinely fly with a multi engine CFI and practice engine loss at altitude. Muscle memory is so important!🙏
Really good video. I do think they are safer for the pilot with the right mindset and training however. I fly a 3 engine big jets as a captain and I own a baron, I have to remember that if I lose one in the baron sometimes straight ahead is the best option, and I need to think about it more like a power loss in a single. I separate the 2 in my mind. It is not gonna fly out like a jet, and V1 is basically blue line in most situation. I tried this out hot and have in MSFS out of Santa Fe after watching your last video, and it’s a bitch. Once or twice I just ended up with an off airport landing. I took off out of Oshkosh yesterday in real life eastbound at max gross weight, and briefed that if we couldn’t land straight ahead and it wouldn’t fly I was gonna nurse it over the houses into the lake just off the end. I also agree about xplane having a better flight model and handling more realistically with an engine out. If you ever need help with the videos let me know. I think your channel is gonna go far.
Thanks for that! Those Barons are nice, but if the numbers I’ve seen for single engine climb are right, it shouldn’t climb out of a 6,000’ airport on a warm day near max gross. I did it out of Centennial airport in Colorado a while back on MSFS (about the same altitude) and got the same results as you (I also had it at max gross). I kind of think that MSFS may have the performance on it turned up a bit. Still, great plane!
Ive watched a few great pilots flyibg twins get in front of the power curve when loosing an engine on takeoff.
1) pick longer runway you can get to 10 knots faster on rotate. Closer to blue line speeds, Never rotate early.
2) dont use flaps, one less step in procedure, choose longer runway.
3) gear up 5 ft above ground. Thats 2 steps left out of procedure during engine out. Removed flaps & gear up steps immediantly. Plus less drag.
4) throttle, props & mixture are most likely set duribg take out so less to think about in emergency.
All are full forward already.
5) pitch for blue line, raise dead on engine 5 degrees, split the ball using rudder.
6) then identify, verify by pullibg throttle on dead engine to idle, feather dead engine & pull its mixture off.
Lastly turn off fuel pump, adjust crossfeed fuel. ⛽️
Either land off field straight ahead best option even gear up & survive landing.
VMC roll is caused by P-factor as much as it is asymmetric thrust. P-factor is why it's worse to lose the left engine than the right engine. The down-going propeller blade takes a bigger bite of the air and therefore, pulls harder than the up-going blade..
Yes, P-factor plays a roll as well. I was mainly focused on the misunderstanding about bank into the inoperative engine, but critical engine is obviously an important concept in many light twins.
@@flyingformoney777Plus, P-factor gets worse as you raise the nose struggling to gain altitude. And, the use of ailerons will cause one wingtip to stall before the other, causing the plane to roll in the opposite direction. Your natural reaction is to add more aileron when that wingtip drops. When my instructor showed me a spin to the left in a Cessna 150, my brain immediately wanted to go to the right side of the plane. It’s not quite as bad when sitting in a chair in front of a computer.. 😎
the algorithm just suggested this video to me and i really enjoyed the in depth explanations.
Very well done…. I’ve have been fortunate to fly/own a Aerostar 700. With one engine (loss of one), it climbs out at 660 ft. But, you can’t be stupid with overconfidence.
Nice plane. If I wasn’t working on college funds I’d probably be working towards one of those…
I have to admit…. They go through the fuel…. While in Top of climb is 80GPH and when reaching top and on the step at around FL 30.. 40GPH @ 65% power. Insurance is $11,700 a year.. Annual is $15,000 +/-. Hanger is 18,000 a year…. Sure makes Alaska airlines sound cheap…. Other than landing at the closest airport possible. Fastest I e ever had her was 435 MPH heading from SEA to CGO with one very favorable tailwind…. And full power to see what she could do.. 😉
@@flyingformoney777 Trade Bitcoin!!
I have several objections with the concepts as explained in this video. Here a few of the most important iones.
The ball 1/2 width off center is not "uncoordinated flight".
Coordinated flight means zero sideslip angle.
When there is no net lateral force, coordinated flight is equivalent to the apparent gravity vector being perpendicular to the wings (which is what the ball actually measures).
But that's not the situation when you have asymmetric thrust. Certainly, when you have asymmetric thrust you want to counter the thrust yawing moment with rudder. However, the way the rudder applies yaw moment is through a lateral force on the fin which creates an unbalanced lateral force. So what happens next? Perhaps it's easier with an example.
Say that the right engine fails. Initially you have an unbalanced yaw moment to the right that you will counteract with left rudder. The left yaw moment achieved by the rudder is via a lateral force to the right on the fin. Because of that unbalanced lateral force, the plane will start to drift to the right/ Because now the wind hits the fin a bit from the right, that will tend to create a left force which in fact will be felt as a reduction of the right force previously mentioned, which in turn reduces the left yawing moment initially achieved with the application of left rudder. So you are not fully cancelling the right yaw anymore. You will need to add more rudder. If you were going slow and you were already applying all the rudder you had, too bad, you don't have more rudder to add, you just lost control of your plane.
So is there a way to cancel the right force on the rudder so we avoid the sideslip and the need to add even more rudder? Yes: Bank to the left enough so as the left horizontal component of the lift vector equals and cancels the right force on the fin. In this way, you can keep zero sideslip and a zero net yaw moment with the original rudder input. THIS IS WHY VMC IS LESS WHEN YOU KEEP A BANK TO THE GOOD ENGINE. YOU NEED LESS RUDDER TO ZERO THE THRUST'S ASYMMETRIC YAWING MOMENT. VMC DOESN'T HAPPEN WHEN YOU RUN OUT OF AILERONS TO KEEP THE WINGS LEVEL. IT HAPPENS WHEN YOU RUN OUT OF RUDDER TO ZERO OUT THE YAW MOMENT and your plane yaws and rolls (as a result of the yaw) out of control.
Note that if you bank the plane to cancel the later forces, you will be flying in a bank but with net zero lateral force and with zero sideslip. THIS IS THE REAL COORDINATED FLIGHT. Yet, the ball will "fall" a bit towards the lower wing because you are banking but not turning. But if you pout a yarn in the middle of the windshield, the yarn will be completely centered.
This applies to all airplanes, prop or jets. There are a few differences between prop an jet, yes, but this is not one of them. This is just rudder compensating the thrust's yaw moment and bank compensating the rudder's unbalanced lateral force. The source of thrust is irrelevant.
The differences between jet and prop are:
a) In a jet you don't need to maintain aileron input to maintain this status. You are in coordinated flight (even if the ball tells otherwise) and the lift is symmetrical. In a twin prop the working propeller will be blowing higher speed air over its wing which will then generate more lift so you will need to maintain aileron towards the good engine to keep the bank constant.
b) Other effects of propellers (like torque and p-factor) will make that you will need more rudder and aileron to compensate the loss of the left engine than the loss of the left engine. Those effects don't exist in a jet.
c) Most jets are required and designed to have an engine failure during the take-off roll at about V1 (which is typically before Vr and before lift-off) and still be able to maintain directional control on the ground, accelerate to Vr, lift off and accelerate to V2 which is the minimum speed you should keep in the climb after losing an engine. V2 is typically much larger than V1. The rudder is design to maintain directional control at V1 and, because the effectiveness of the rudder goes with the square of the airspeed, by the time you reach V2 you have plenty of rudder authority so the bank technique is not really critical. V2 is well above Vmc. In a prop twin, Vmc is Vmc so if you are flying at Vmc you have ero margin, you NEED that bank to maintain control, and the blue line (the minimum speed you should keep when climbing on a single engine) is typically not much higher, so you have margin but not much, so the bank technique is still critical.
Finally, I don't know where you got that wrong notion that Vmc changes with weight. Unlike the stall speed, it doesn't. And the reason why one does and the other doesn't is easy. Lift counteracts weight, and weight depends on weight. Rudder counteracts thrust yaw, and thrust and it's lever arm do not depend on weight. What does depend on weight is how much bank you need to keep the zero sideslip condition. The heavier the plane the larger the lift so you need a smaller bank to achieve the same horizontal component of the lift.
If the max bank into the good engine is restricted (by policy) to 5degrees than wouldn’t that result in a higher Vmc for the lighter aircraft?
@@yamashill ... Higher Vmc compared to what? Yes, if you allow more bank angle, your Vmc will go down to some degree. But your stall speed will go up.
Physics and aerodynamics doesn't care about policy. But would you like an airplane manual to say that the Vmc of the plane is 70 knots and that it requires 30 degrees of bank for straight coordinated flight?
@abd12: In all honesty, I made this video for people just like you, who have a TON of misconceptions about this stuff. There is a persistent yaw with ball out of center, plain and simple. The 5-degree bank is there to maintain heading because of that yaw. It has NOTHING to do with “canceling” yaw (if you canceled yaw, there would be no ball deflection).
And though jets don’t have p-factor per se, they do have rotational effects very similar. With the exception of the rare counter rotating engine, all wing mounted twins have a critical engine for this reason.
To the degree any of your objections have merit, it comes down to definitional differences. What is meant by “coordinated?” If you are referring to orientation with the slipstream, you are at least partially correct. If you are referring to yaw, you absolutely are not.
And Vmc is 100% dependent on weight. Do not mistake published Vmc speed (which is established based on the worst case scenario of light weight) with the ACTUAL Vmc speed (the speed at which rudder/aileron authority is no longer sufficient to counter yaw induced rotational forces).
Yes, 5-degree limit can result in a slightly higher Vmc speed, but is included in the “published” Vmc speed.
@@flyingformoney777 ... You are saying things but you are not explaining why. I did explain why.
"There is a persistent yaw with ball out of center, plain and simple" Why? I claim that not. And I explained why. But here it is again and expanded. The ball is just a ball in an arched tube. Has the same function than a highly dampened pendulum. It will just point in the direction of the apparent acceleration (one component of it anyway). If the airplane is parked in an include ramp, the ball will be off-center and there is no yaw (or, more correctly, sideslip angle, since "saying "there is yaw" is like saying "there is pitch"). You have vertical component of lift cancelling weight, rudder yaw moment cancelling thrust asymmetry's yaw moment, lateral component of lift cancelling lateral force on rudder/fin, and the plane is in equilibrium of both forces and moments, flaying straight, and banked. There needs to be no sideslip (the yarn on the outside of the widescreen would be perfectly centered) and the ball is off center. Explain what of that is wrong and why.
"To the degree any of your objections have merit, it comes down to definitional differences. What is meant by “coordinated?” If you are referring to orientation with the slipstream, you are at least partially correct. If you are referring to yaw, you absolutely are not." Please define what you mean with "yaw" and how does the ball measure it. I try to avoid "yaw" because it is confusing. Yaw can be just an axis of rotation, and an angular position (or displacement) about that axis relative to a zero reference. The movement about this axis is normally called "yaw rate" (what the stick of the stick-and-ball instrument measures). Similar with pitch and pitch rate. The action of yawing is the action of changing the yaw angle, like pitching (up or down) is the action of changing the pitch angle. Sideslip, on the other hand is the angle of the plane relative to the slipstream, like angle of attack, but lateral. The relationship between yaw and sideslip angle is the same than between pitch and angle of attack. So what do you mean with "yaw"? Sideslip or lateral angular velocity (i.e. heading rate)? Or something else?
In any case, what you want to do is to keep the plane flying parallel to the airstream to minimize drag and keep rudder authority. So yes, I care about sideslip angle being zero, which in an asymmetric flight condition means that the ball must not be centered.
"And Vmc is 100% dependent on weight. Do not mistake published Vmc speed (which is established based on the worst case scenario of light weight) with the ACTUAL Vmc speed (the speed at which rudder/aileron authority is no longer sufficient to counter yaw induced rotational forces)." Again, no. Vmc is the speed at which you run out of rudder authority, not aileron authority, and that doesn't depend on speed. The only reason why you need to keep aileron input at all in a prop plane (other than torque and p-factor) in an one-engine-out condition is because the good engine is blowing air over a part of the wing increasing that wing's lift, but the failed engine is not. But in a jet (or a twin prop like the Avanti), you don't need any aileron input to keep the plane form rolling one way or the other (assuming you are using rudder to cancel the asymmetric thrust's yaw moment) so you are never going to run out of aileron... but you still have a Vmc.
In my opinion, you are the one that has many misconceptions, not me. And I am explaining why. But in any case I don't want this to be a "who is right / who is wrong" pissing contest. If I am wrong I want to understand it. Understand it, not just believe it. That is why I am asking you to explain why what I say is wrong and why what you say is right. And I am offering the same in exchange.
Your attention to detail in explaining the effects of asymmetric thrust as amazing. I never thought of the trained use of rudder, and how it is adversarial in this case. The Santa Fe accident scared me (I fly a 310R), particularly because the pilot must have been a great stick&rudder, but you may have a point. That said, it was a turbo, so would it not have had more climb performance at 9000 feet density altitude, even with average technique. The NTSB will report if the failed side was feathered, and if that remaining turbo was operating.
Best explanation of the topic I've encountered anywhere. Got yourself a new subscriber. Thx!
Thanks! Welcome aboard!
I would say that an extra engine DOES make you safer for the most part. There are some caveats though that can get you in trouble, especially at slower speed, i.e. taking off or landing. Here you can get in trouble for sure if you are not ready or proficient.
Two engines doubles your odds of an engine failure. So, for it to pay off, it needs to double your chances of avoiding a crash landing. There seem to be a lot of twin crashes so I am not so sure it really improves the odds.
Great video once again. I really appreciate these videos. Keep up the good work
More to come!
The idea behind the twin and safety assumes that you are properly trained and have the experience to handle a twin engine, and complex (constant speed prop, retractable landing gear) aircraft. If properly trained the twin provides a safer flight. The buffalo and the "pusher pull you"cessna" are exceptions given their single engine performance.
Your bank angle analysis is ABSOLUTELY CORRECT! The Bank Into the failed engine is BS!
The rudder AND airspeed is the savior of the failed engine situation. After 50 years and 20K flights hours,
YOU finally are telling the truth about "coordinated flight" to survive an engine out situation!
Good on you for properly explaining this life changing emergency!!
Old ATP; Venice,FL
Just a great job in this video. Very comprehensive, never getting off topic. I've brought nine back with one feathered, and the advice here is spot on.
I received my multi-engine rating in a Piper Seneca with counter rotating props vmc was fairly minimal but while training with a Piper Navajo with turbo engines I had to demonstrate vmc and recover. Then my instructor feathered my left engine and did some air work and turning into the dead prop I had to make a landing with the left engine shutdown and making normal left turns in the pattern. All very stressful even with the instructor along. Think what it would be like IMC at night! I flew that Navajo many many hours and thank GOD I never had a engine failure. I do think counter rotating props do help a bit with the VMC problem but there is a Macho feeling out there with pilots. Trouble flying a twin one one engine? Then fly a single! I did saw a demo pilot flying a souped up Navajo do a left engine feather on take-off at 25 ft agl Ever see Bob Hoover fly his Aero Commander he was the VMC expert!!
A stellar voice in safety and fluency, you are making the air safer with each video. Thank you
Thanks for that!
Fascinating and yea I wouldn’t put myself in a twin that has a critical engine namely both have to be counter rotating, and secondly doesn’t have an auto feather
Too much to worry about when things go south and very rapidly.
This is one of the best videos I have I seen.
Thanks!
@@flyingformoney777do you have a website/email I could reach you on?
You can email me here: stan@bellmanmultimedia.com
I've seen a 402 take off , lose one engine , then a few seconds later went into a Vmc roll.Confusion as to which engine died was chaotic as I was later told , the pilot brought the working engine to idle , recovered from the roll , landed straight ahead and wrecked the Airplane. The four occupants survived. A lot or recurrent training would have prevented this but at the end ,the passengers and pilot are still around. Great tutorial by the way ! thanks !
Quite a story! Thanks!
Excellent! Like John, below I am also a long time guy who is now spoiled because I fly jets. We don't even consider many of the points in this video because we have so much power available. Yes, the plane needs to be trimmed out for the engine out situation but we don't think twice about turning into the good engine. We just trim and fly. Not so when I flew the Dash8. Plenty of power on that plane BUT the massive props way out on the wing coupled with the massive rudder meant that you had to get that thing trimmed out right in order to relax on one engine. This is an exceptional video and should be required viewing annually by anyone who flies a light piston twin. Or, a fully loaded and heavy King Air, etc.
Superb, nice contrast and complement to blancolirio who deals with stall spin accidents all the best. Nice work!
Man, so much trash talk in these comments! This video was good info. Every time I took off in a twin Cessna, I visualized flying it to an off airport landing after losing an engine. You have to be okay with that outcome if you fly light twins. If you *happen* to have enough airspeed / altitude to make it back, then great! The moment an engine fails, the insurance company owns it. Airspeed and keeping the ball centered is 1000x more important than anything else.
If rolling over, kill the good engine and nose down and you MIGHT still die. Don’t kill the good engine and lower the nose, you WILL die.
Thanks for all the information you provide in your videos. I really appreciate learning about things like this.
Glad you enjoyed. Thanks!
Great video. As with everything: keep your airspeed (keep those controls pushed forward) and leave your feet off the pedals.
Why would you leave your feet off the pedals?
Very professional presentation.
Absolutely brilliant explanations. Best I’ve read, seen, or heard; ever. Good lord brother, not all of us are so goddamn bright 😅 Could you talk a little slower for those of us on the average part of the spectrum?! Thank you for considering. What a treasure to find your channel. I’m watching this video another four times.
Yeah, I think I’m gonna have to go back and watch at 0.5x just to digest each point of info! 😂 Data was comin’ fast!!
I think I see your point. The 5* angle of bank toward the good (let's say, Left) engine serves to balance the plane so it will fly essentially straight through the air. The ailerons will however, create a (add to the) starboard yaw that must be countered with slight rudder.
The rudder is deflected to counteract the yaw due to asymmetrical thrust. Nothing else. The deflected rudder gives the airplane a small sideways force. This is corrected by banking a few degrees into the good engine so the sideways component of Lift neutralizes the sideways force of the rudder.
When flying correct on one engine the ailerons should be close to neutral. This is straight out of the Flight Crew Training Manual from Boeing. Don’t listen to this clown ‘Flying for Money’
The 5 degrees is not exactly, VMC air is determined by the certification with maximum 5 degrees bank into the good engine. Not necessarily 5 degrees. Could be 2 or 3.
Hello, very well done. The accident reports are still full of VMC accidents in twins. I too practice engine out procedures on FS2020 and XPlane 12. It does train your thinking enough that reacting to an engine failure becomes automatic after Sim practice. I sometimes look off to one side and then fail the engine to simulate it being a "surprise". No one should fly light twins without being ready to properly handle the airplane on one engine. Thanks.
Too many words. What was the failed engine short list? Trim Rudder towards the active engine, active engine wing down 5 degrees while using attitude to control speed and feathering the failed engine prop?
But which direction should you turn to make a quick return to the field, and should you even try? Immediate action items are a fine resource, but a little knowledge is never a bad thing.
@@flyingformoney777 I’m not criticizing the knowledge, understanding is vital, but I got completely confused as the video images seemed, to me, to be contradictory. This exact case was a famous Beechcraft Super King Air accident at Sydney Airport in 1980 killing 13 people. I’d like to understand if the situation was survivable. It all happens in such a short period of time, this is where reflexes are equally vital.
Good explanation, Im keeping my 337.
This is very well explained. Thank you!!
These twin engine light planes seem to be death traps. Especially when the engine failure is on the problematic side.
I understand that this is because the swirling prop wash degrades lift on the functional side.
Would this be less of a problem with pusher props?
Glider pilot here, and I don't understand. Skip if you wish.
So, does the typical twin generate significant adverse yaw from the aileron that is pointing down (which has a long moment arm - being out on the end of the wing)? If so, then banking into the dead engine increases the adverse yaw into the working engine, lessening the rudder input required to keep the aircraft from turning into the dead engine (because the dead engine side is cleaner)? It would seem there is little margin before a roll into the dead engine begins, even though that side is cleaner (from the wing's perspective, not the engine's).
By modulating a relative slip into the working engine, with a little rudder into the working engine, one would have a hard time turning into the working engine. Of course, the airplane wants to turn into the dead engine.
The aileron doesn’t do much to a (compared to a glider) heavy twin. Most of the yaw is from asymmetric thrust. We don’t really consider aileron effects with regards to Vmc.
I flew the exact profile and executed as accurate the scenario reported on the 310 crash in X-Plane and was unable to recover 4 out of 5 times - funny thing is the successful flight was a result of leaning in to the good engine - I had very few options that I could notice in the struggle in that scenery and it was a handful from the get go, it made me feel so sorry for the PIC it was a horrible situation he could never be adequately trained for.
Hi ,at the 11.42 clip, I would like to ask, Could use a hobby model ,to demonstrate the maneuver your explaining? Or use vr to show us the maneuver? Thanks
Retired Airline Captain and CFI II MEI - Well done sir!
Thanks!
Excellent. This is mind-blowingly well prepared and explained.
Thanks!
There is a lot of good info here but I would quibble with your Vmc definition. It’s not necessarily the speed at which you run out of aileron. It’s the speed at which you out out of control in any axis. Depending on the bank angle you can run out of rudder first, which means you can’t maintain heading, or you can run out of aileron first, which means you can’t maintain bank. I have worked on the design of airplanes which encounter both conditions. Perhaps light twins, which are only aileron equipped, always run out of aileron first. The larger Biz jets tend to have spoilerons as well so they tend to be rudder limited. The Vmc demonstration for FAR 25, as described in AC25-7, allows up to 5 deg of bank into the good engine. This allows you do reduce the rudder deflection for a given speed, or reduce Vmc at full rudder, at the expense of higher aileron requirement. Why? Because you generate more proverse sideslip. This helps the directional axis but the resulting sideslip requires more aileron to keep the good engine down. That 5 deg bank will allow a substantial reduction in Vmc if you are not aileron limited. If you are roll limited then you can really use it.
Yes, very complicated, airframe to airframe issue. Thanks for the note.
Excellent, fascinating and informative. Nicely done buddy.
Thanks!
Great explanation...thank you.
Fantastic explanation. Thanks for taking the time to do this.
Glad you appreciated it!
I’ve not flown a twin. If I lost one engine at low airspeed, I’d reduce power and push the nose down to gain AS and aileron control, then bring RapM’s up.
I think that if I was close to the ground and slow on takeoff, I’d dial in just as much power as the controls could handle. If this was not enough to climb, it would at least extend my glide and options.
Remember, the book number are performed by a qualified test pilot. So if your not proficient, don’t expect much. If you look like your loosing it in with engine failure in a light twin, close the throttle on the good engine and play like your a single ending ac with an engine failure. Takeoff in a twin with an engine failure is a tough senecio. But it you suffer an engine failure at altitude you stand a much better chance of a safe landing than in a single ac.
Thinking about aileron authority, slight sideways flight path, and vmc. I wonder if the large tip tanks contribute to a loss of aileron authority by disrupting airflow slightly over the aileron given a slightly sideways flight path? Not saying tip tanks caused the crash, but Im wondering if it might of contributed or if a wing clear of tip tanks would have performed slightly better?
That Was Really Great! Surely You're A CFI Or Lecturer At Some Aviation School. What's Your Take On Counter-Rotating Engines In The Same Situation? Thank You.
I think that, even though it may be true that banking into the dead engine can be done in very controlled circumstances, and knowing that pilots will always take the easy way out in a desperate situation, I don't tell people it can be done, unless they are going to die if they don't. Once you plant the seed of turning into the dead engine is ok, someone is going to get killed.
I used to read aviation consumer back in the 80's and they had an article about the Cessna 414 where the company hired the best pilot they could find to fly it on one engine and sure enough, it ended badly.
Did you mean C411?
@@thomaslembessis6803 may have been
WOW, so far above and beyond the textbooks! A little clean-up and editing, and license this vid to Flight Safety Int'l/Sporty's/etc. 👍👍👍
Expert analysis. Been a long time since I flew single pilot charter in my turbo twin Comanche. No one gets enough exposure to this kind of critical performance training.
Awesome explanation..thanks
You were soo close.
Vmc is when "the Rudder" looses directional control and the plane yaws due to lower air speed & asymmetrically thrust from operating engine.
One wouldnt want to use ailerons input during a stalled plane with yawing tendencies.
A plane will not Spin when stalled if it does not yaw. One needs both stall & yaw to spin.
Last but not least is in light twins its not just stall or a spin or a wing drop but VMC ROLL.
This is when the twin pancakes, rolling inverted onto itself if below red line on airspeed indicator & rudder authority is lost.
Close, but not totally right. The wings do not stall in a Vmc roll, and aileron input is inevitable when a plane is flown with the ball half out of center. The roll part of Vmc roll is due to the rolling forces produced by asymmetric thrust overcoming control forces. Low speed loss of effectiveness of the rudder AND ailerons is what causes it.
@flyingformoney777
Notice what sim helps one feel what it's like better. You said X-Plane shown better simulation loss of engine.
Any single engine plane do a lifelike wing drop when stalled or accelerated stall that you've found yet?
I haven’t noticed much of a difference between sims on wing stalls. I think they both do a reasonably good job.
Have you found that traditional steps work with twins.
Full props, throttle & mixture response is best?
Excellent video for the Pre-Student!
Further to my last comment, I would recommend that every pilot read 'Stick and Rudder' by Wolfgang Langweisse. This has been my flying bible for 30+years and although written in 1930 it is very relevant with all aircraft. A thorough understanding of flying the wing which, is all you are doing really will save a lot of lives and misery. Too many treat it like driving their car and an instructor or pilot that has that mindset will crash
You have lots of good information here, but there are also several inaccurate statements. A few of them are: Coordinated flight is possible and desirable in OEI flight, but it requires a yaw string to find it. And, more bank is not better, and most aircraft 3-4 degrees is the optimum bank angle, 5 degrees would be too much.
Thanks for the comment. It depends on what you consider “coordinated.” If you’re referring to aligning the slipstream with the aircraft, you are correct. If you are referring to the “sideways” feeling when the ball is out of center, you are not. I’m not sure what you mean by “most aircraft.” Optimal bank is highly dependent on many factors, so it does vary.
Superb explanation of a complex subject!
Thank you!
no doubt . listening im going what?
Good luck on the turn into the failed engine. Is your experience purely on MS training aid?
Nope. 8000 hours flying plus another 3000 in the sim as a check airman. You?
You think that you can only turn towards the good engine after a failure? You might want to check around on that…
Do a booklet on these concepts as described by you with lots o illustrations please?! Third time watching and still taking notes! Bravo 🎉good sir. Thank you.
Very informative thanks. Off to X plane to try it out and see if I can do the 5 deg bank 1/2 ball. Should be a challenge. Find flying the Barron 58 a challenge anyway. 😅😅😅😅😅😅😅😅😅😅
Wow. Regardless of how right you might be, getting all this straight, after you’ve already lost 20 IQ points merely by sitting down in the left seat… and then having to overcome several seconds of startle factor… seems like a nearly insurmountable task. I’m wondering if it might be best to pull power on the good engine (probably psychologically impossible, never mind the time spent identifying the good engine) and fly into the crash.
Yes, sometimes we brief for that if we lose an engine below 400' AGL on takeoff. We pull back both throttles, so we're guaranteed to retard the good engine! No need to figure out which engine is the good one!
Thank you well explained. You've got another subscriber !!
Welcome! Thanks!
Going below VMC doesn’t over power Aileron authority, it over powers rudder authority.
The aircraft rolls even with full, opposite aileron so yes, Vmc is partially about the loss of aileron authority. From an engineering standpoint the rudder more or less determines Vmc, but from a pilot’s standpoint uncontrollable roll is an aileron issue. Flip sides of the same coin.
I see. Nothing new for me. At low speeds (high AoA) It is better to use rudder pedals to roll. Because using ailerons may cause the assymetrical stall.
True if you are close to stall speed. Vmc isn’t a stall though. It’s the point where you run out of rudder to counter yaw, resulting in uncommanded roll. Rudder is important, but pilots are generally more attuned to the yoke/ailerons.
@@flyingformoney777 Thank You for explanation.
Just watch Bob Hoover, and smile. 🙂
I seriously appreciate your videos sir!!
Thank you!
We never hear about multi engine failures and good landings. Not news worthy.
It's easy to defend my comment. Your statement that VMC is dependent on aileron authority is simply incorrect. A VMC roll is prevented by countering yaw into the dead engine using rudder, rather than with aileron input. Loss of rudder authority makes the increasing yaw and bank into the dead engine impossible to control even WITH aileron input. The same applies to attempting to prevent a stall/spin on the base to final turn. Aileron input to counter the increased bank toward the low wing simply increases the inside wing's AOA and brings it closer to a stall and the aircraft closer to an incipient or fully developed spin.
Far more experienced pilots than I am have also criticized your video.
JF ATP CFII MEI
I added a comment 30 minutes after I posted the video noting that Vmc speeds are established by rudder limits. I just did another video clarifying this. The definitions are obvious and so I assumed them in the first video.
Vmc roll is different than a stall/spin. And to be clear, I never said that Vmc was dependent on aileron authority. I said that the rolling forces that occurred below Vmc were too significant to be overcome by the ailerons. And your last statement is pretty abstract. An empty appeal to an unnamed authority. Let your words stand for themselves.
I’m not sure your explanation of the effect of higher weights is correct. In steady state flight, inertia effects are zero (no acceleration). Rather, at higher weights, in a bank some of that weight is counteracting the force from the rudder defection, reducing total lateral load for the same rudder deflection, or looked at another way reducing required rudder defection for the same amount of side slip.
I was abstracting a bit on the weight part to keep it simple. More weight means more lift. At half ball, regardless of attitude, deflecting lift allows the aircraft to be oriented with the slipstream while using less rudder, like you said.
Multi training in one week. I'm gonna re-watch this video about 20 more times.
WOW awesome. did you ever read the book stick and rudder? what did you think of it?
I haven’t, but I’ll have to check it out!
@@flyingformoney777 it's an oldie (1944) but goodie. I read it while taking flying lessons years ago and I thought at the time that if a person read and understood this book he could probably learn to fly after one or two lessons. here's a link, and no, I get no commission, but you could try look inside stuff. Good luck!
“Bank 5 degrees” *proceeds to bank 20*
“VMC Spin”? Oh for goodness sake, the VMC issue is NOT a spin and the loss of yaw/roll control looks NOTHING like a spin.
You need to explain more, because I’m not sure what you mean. The aircraft rolls uncontrollably and noses over. Try it on a flight sim (I wouldn’t suggest it in real life). The two look very similar. That’s why they call it a “Vmc spin.”
Is VMCA speed determined only at full power on the operating engine?
Great video thanks!
Yes, full power is one of the determining factors. Vmca is basically a measuring stick using a set criteria based on worst case scenario to gauge single engine handling and performance. That is failure of the critical engine and it is windmilling, maximum power set ( at sea level) on the live engine, either full rudder deflection or a nominated amount of rudder force e.g. pilot applying 150lbs force on the rudder pedal, 5 degrees bank towards the live engine, flaps set for take-off, landing gear retracted and aft Centre of Gravity.
So if we change something to the criteria, it will change the Vmca speed. For example, a forward Centre of Gravity will give you more leverage from the rudder. More rudder authority, lower Vmca. Not having full travel of the rudder or cannot physically apply sufficient pedal force, higher Vmca! I had a student once who was quite petite. She went to the gym to build strength in her legs so she could control the aeroplane during her multi engine training. She's a 737 pilot now. Hope this helps.
@@flashpuppy167 Thank you so much for your explanation
23.149 in the old version of part 23.
FlyWire and Blancolirio both say twins spins are basically unrecoverable, so don't get in one. Agree? I think I do.
Another video I watched made another point that uncoordinated flight with too great an angle of attack relative to the vertical stabilizer causes it to stall and that's what initiates a snap roll. Scary! ruclips.net/video/VcEg39NmxY4/видео.html&pp=ygURbWFydGluIHBhdWx5IHR3aW4%3D
A question. Blue line represents Vyse, but doesn't that assume that you have excess thrust available? In a situation where you can't maintain altitude single engine at Vyse, could an airspeed closer to minimum drag possibly allow you to maintain altitude, and how does that speed compare to Vyse?
It will be interesting to hear what @flyingformoney has to say. My very outdated two cents: Decades ago, my multi engine CFI and I took a 310Q to 9,500 feet during a warm summer’s day and we played around with it a bit. Vyse seemed to give us the best minimum descent rate. We didn’t fully shut down the critical engine, it was just providing zero thrust. 150 fpm descent was the best we could do and that was at Vyse.
You can obtain a better angle of climb at Vxse (sacrificing rate of climb), but the best “single engine glide ratio” (if you cannot climb at Vyse) is achieved by maintaining Vyse. You might be able to decrease the sink rate slightly at a lower speed, but drift down range will be less as well.
In a 310R, Vxse is 85 knots, and that's close to Vmc (80), but Vxse is actually lower if you're lighter than max gross (which is likely, and that Vmc is given for lowest weight). So that's not a good idea. The manufacturer defines Vsse, which is 92kts indicated in the 310, to keep you away from Vmc.
Vyse is not a glide ratio. It represents best rate of climb airspeed with an engine inoperative.
@@flyingformoney777 At any rate, we are probably talking about 100fpm at most, and I would bet it is probably less. In any scenario, flirting with Vmc is a bad idea. It's mostly a mental excercise in trying to understand how it all works in a situation where you have a thrust deficit at Vyse.
Find the best scene for the crash ....i like that one
Ailerons have nothing to do with it
RUDDER stop the yaw this will stop the roll
Slight bank towards the live engine will help performance but always control with rudder first
Only recently came across your excellent concise, data dense channel. Thanks for your work.
Thanks!
A1 video!
Running engine takes most of em to the point of impact. Raise the dead!! - Mr Addams, Addams Family Pinball circa 1994-ish
2nd engine DOES, just not when it's not working lol
Probably have to watch this 100 yimes to get it straight.
Great video
Thank you!
Great job
Thanks!
Thanks!
Thanks! Appreciate it!!
Just hope it never happens to you.
I disagree with your assertion that Vmc is a function of weight. First, it's not that higher weights move less, its that higher weights accelerate more slowly, they still move.. As you approach Vmc, rotational speeds are zero anyway. Second, Vmc has to do with counteracting airframe rotation, so angular momentum is in play, not linear. This means that in any rotation the airplane responds to an angular moment of inertia, not plain mass. Third, Vmc is derived from rudder effectiveness vs off center thrust. Rudder effectiveness is a function of the rudder force AND the length of the rudder arm from the center of rotation in the yaw axis, ie the lever arm. So CG location plays a factor in Vmc; aft CG raises Vmc. Fourth, Vmc has to do with asymmetric thrust which produces (mostly) yaw, and is balanced by rudder. Vmc is about balancing these two forces, and specifically when they are no longer able to be balanced. As others have mentioned, ailerons are very secondary.
Weight's most pronounced effect is reducing climb performance The greater rotational inertia (if any) will only slow the rate of turn entry or turn cessation. It will not change Vmc.
i like that you mention reducing thrust on the good engine to maintain control. Many teach chopping power completely, not necessary if you react at the onset of Vmc. As you begin to lose rudder authority, reducing power on the good engine will reduce Vmc. Placarded Vmc is at full power, and of course you can always change that. This is important when trying to stretch a powered descent into terrain, you have more time to choose a spot if you fly with reduced power on the good engine. By reducing power, you can bring actual Vmc to below stall speed.
A few counterpoints. If you accelerate more slowly, over time you move less. I’m not entirely sure what your definition of “move” is, but mine is: lateral distance traveled per foot of forward distance. And “rotational speeds” (I assume you were referring here to yaw) do NOT go to zero at Vmc. Rotation is a result of asymmetric thrust, which (in a prop) does not change much as airspeed decreases. If you were referring to roll forces, at Vmc the ailerons and rudder are still producing rotational forces, but they are no longer enough to overcome rotational inertia. While we're at it, you mention inertia while simultaneously dismissing mass. What is inertia? It is “the sum of the product of mass.” I use the word “mass” because it is central to inertia, and something that everyone understands intuitively.
This leads to your first complaint, that Vmc is not a function of weight. It is. Google “Vmc and weight.” If you won’t believe me, maybe you’ll believe all the other resources out there that draw the same conclusion: the lighter an aircraft is, the higher “actual” Vmc will be. I don’t disagree about Vmc being dependent on rudder authority, but the end result is uncontrollable roll, which is a function of the ailerons. As far as the pilot goes, Vmc is when roll can no longer be controlled, and flying with the ball “half out of center” decreases Vmc speeds because the ailerons are more effective while simultaneously less rudder is required. Ailerons are not “very secondary” to this equation. They, along with the rudder, are prime players.
@@flyingformoney777 Replying to your points in order:
I used 'move' in a colloquial sense. The point there is that acceleration of a larger mass will result in a slower acceleration, BUT THAT DOES NOT INFER AN INCREASE OF Vmc. It only infers the rate of increase of the speed of the yaw and roll. And pay attention to the fact that while the higher mass accelerates more slowly, it will also decelerate more slowly. Stopping the roll or yaw will be more difficult. (This still only applies to rotational moment of inertia, the equivalent of mass in rotational dynamics. In aircraft, higher gross weights can mean weights near the CG, like passengers, or far from the CG, like tip tanks. It's not a one size fits all) Vmc is not about the rate of uncontrollable yaw, it is about the airspeed at which yaw becomes uncontrollable. And that happens independent of aircraft weight.
'As you approach Vmc, rotational speeds are zero anyway.' means that as airspeed slows and the aircraft approached Vmc, there is no uncontrollable yaw yet. You are still under control. You have not yet lost rudder authority and can still fly straight. At Vmc, you have not started to rotate about the yaw axis, that happens below Vmc. By definition. So yes, rotational speed is zero in a properly flown aircraft at Vmc.
Nothing ever will "overcome rotational inertia". Rotational inertia is conserved, much like mass, unless you rearrange fuel or passengers. Since you usually don't have the time to do that, it is a constant. I don't think you understand what rotational inertia is. Much like linear inertia, it affects the acceleration of a mass. The mass always responds to a force. It is not overcome. And you get the definition of inertia wrong. In rotational dynamics, it is the sum of the products of the masses times their respective arm.
And no, Vmc is (still) not a function of weight. Your internet reference is wrong. This is a great illustration of just because it's on the internet doesn't mean it's correct. If you are referring to this page:
thebackseatpilot.com/pages/vmc
look at the accompanying diagram. Note that it states that Vmc occurs when TxX (thrust times the lever arm of the engine from the CG) equals RxY (Rudder force times the lever arm of the rudder from the CG) This part is correct. Note that nowhere in this correct representation of Vmc is mass of the aircraft, or any part of the aircraft, in the equation. It is only the asymmetric thrust rotational force vs the rudder rotational force. Mass doesn't matter. What matters is when the rudder force available no longer is sufficient to offset the asymmetric thrust (and the added asymmetric drag of the windmilling propeller if not feathered) the aircraft becomes uncontrollable.
Flying with the ball half out decreases drag, and therefore increases SE climb performance, it does not decrease Vmc. I'll leave it to the reader to look into that one further. Suffice to say moving the ball to any location does not affect rudder authority or asymmetric thrust, so Vmc remains the same. And where did you ever learn that at slow airspeeds ailerons are equally as important?
Lastly, the published Vmc is derived from the most adverse (but still legal) conditions. It will never be higher, but it very well may be lower.
I'm taking the time to go over this in detail (mind numbing as it may be) as it is important to keep low time twin pilots well informed, and hopefully prevent an accident.
@@midweekpowderhound "Move" means motion, and mass resists motion. Even in the colloquial sense. From CFR 23.151 (f.5): Vmc is established by: “The most unfavorable weight in the range of takeoff weights.” You link to one source and dismiss it, but there are many, many other sources out there that mirror this statement: “The most unfavorable weight of a multi-engine aircraft is when it is lightest…. Early certification of multi-engine aircraft did not specify the weight at which Vmc had to be determined. Therefore, many manufactures calculated Vmc at the heaviest weight resulting in the previously mentioned effects on Vmc to be reversed. In this case, actual Vmc matched published Vmc at the heaviest weight and increased as weight decreased.”
I’m going to give you this point: the adverse effects of increased weight on performance are far more important than the slight reduction in Vmc that heavier aircraft demonstrate. But weight does, indeed, impact Vmc. For more: AC-8A: FLIGHT TEST GUIDE FOR CERTIFICATION OF PART 23 AIRPLANES: Page 60 and Section 48(c)(1) states that 'The critical loading for Vmc testing is generally minimum weight and maximum aft c.g.; however, each airplane design should be evaluated independently to be assured that tests are conducted under the critical loading conditions.'
Likewise, flying with the ball half out of center decreases Vmc. You state that it has no effect on Vmc, only drag. CFR 25.149 (b): “VMC is the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine still inoperative and maintain straight flight with an angle of bank of not more than 5 degrees.” You need to understand that maintaining level flight with a 5-degree bank requires the ball to be half out of center. The rule of thumb is that for each degree reduction in bank (below 5-degrees) Vmc will increase by 3 knots.
And I understand rotational inertia. Mass is still in the equation for determining it. Heck, you mentioned it in your own definition. And you’re misquoting me on this particular complaint. I was referring to mass as it relates to “5-degrees, ball out of center,” for which it is valid. I wasn’t referring to rotational inertia.
I would LOVE for you to detail how ANY of this pedantic conversation is going to “save lives?” There are only a few main points to everything I said in the video (and yes, videos like these are reductionistic purposefully in order to drive home the main point and avoid intellectualist mire). Here, again, are the important takeaways: maintaining airspeed with a margin above Vmc is vital; Vmc varies and is highly dependent on maintaining ball half-out-of-center; if you cannot climb at Vxse or Vyse, accept it and find an off-field site. THAT is what will save lives, not our little pedantic argument here over definitional terms and the validity of sometimes contradictory source material.
@@flyingformoney777 I don't think higher weight reduces Vmca because of higher inertia. I believe higher weight gives lower Vmc than a lower weight when turning into the good engine (and conversely higher Vmc than a lower weight when turning into the dead engine) because the higher weight means that the wing has to generate more lift to maintain altitude, and therefore the horizontal component of the lift vector for a given angle of bank into the good engine is higher, lessening the need for rudder force to counteract the yaw produced by the good engine.
@@igclapp That is the official reason, higher lift. Unfortunately the official material implies that Vmc is only valid when in level flight with an offset bank. Lift increases in a turn if altitude is maintained (regardless of the direction of turn). The lift vector does not change relative to the slipstream if half-center ball is maintained. What happens to Vmc in a 20-degree bank into the failed engine? If it increases, then published Vmc would only be valid for turns into the good engine (and all POHs would have to caveat this point). This is clearly not the case. Aerodynamically speaking, the aircraft doesn’t care which direction it’s turning, only that the ball is half out of center. “Bank into the good engine” is simply the means to maintain heading. My “weight moves less” thing is an abstraction. You’re right, it’s not a perfect one, but it’s simple and the conversation becomes dizzying pretty quick.
It's an issue that always vexed me. However it would be very insttucted and more useful if you could provide with a simpler and graphical illustration of a stationary image with the forces at wotk under such contingency.
It's a 15 min video, not a week long ground school.
At seventy two you need a safety pilot no matter what. Get real. That isn't what you're clay lacey.
Really great explanation. I would agree with one of the comments below, "best 14 minutes on piston twin principles on YT." Great job
Thank you!
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