Teaching the VMC demo during ME training

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Big Pistons Forever
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Teaching the VMC demo during ME training

Post by Big Pistons Forever »

I was recently asked for advice on conducting the VMC demo as part of teaching the ME rating.

I thought I would pass on what I said. As always it represents one data point and should be examined critically like all advice on anonymous internet sites. It is intended to start a conversation so I hope others will jump in with their (constructive) thoughts.

So for the VMC lesson ground brief:

Start with a description of the forces acting on the aircraft and how weight,CG altitude etc etc effects the actual VMC speed for any particular set of circumstances.

Then you want to situate where the VMC speed fits into the flight regime. The key message here is that VMC should be thought of like the stall speed. The goal is to never be at that speed so recognizing and avoiding single engine flight at or near VMC is the goal. Like a stall, reducing speed below VNC will result in a departure from controlled flight and immediate and correct action is required to regain controlled flight, that is what will be practiced in flight.

Finally it is important that the student understands that VMC relates to single engine control-ability not single engine performance. For almost all piston powered multi engine aircraft VMC will be so far below VYse that the aircraft will have negative climb performance. This is obviously important when the aircraft is near the ground as substantial altitude will be lost accelerating from at or near VMC speed to VYse where the aircraft will (hopefully) have positive climb performance.


For the air portion:

The object of the exercise is to be able to recognize and identify the yaw associated with an asymmetric thrust induced loss of directional control and then correct the situation by reducing power on the good engine and regaining directional control. They should also gently pitch down as they are recovering control. Practice this enough so that the correct actions are taken without any prompting from you.

Safety concerns

1) Have lots of altitude. I won't do any low airspeed ME practice exercises without at being at or above 4000 ft AGL.

2) Many of the popular trainers have a VMC that is not that much higher than the stall speed. Thrust decreases with altitude which lowers the VMC. The possibility is that the airplane will stall before you see the VMC induced yaw. This obviously very very bad. I deal with this situation by limiting the students rudder travel to approximately half that available by blocking the higher rudder pedal with my foot. This will cause VMC to occur at a higher and safer speed.
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B208
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Re: Teaching the VMC demo during ME training

Post by B208 »

....or, do it in a simulator.
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Re: Teaching the VMC demo during ME training

Post by PilotDAR »

All those decades ago, I was trained Vmc by actually doing it. I've never had a problem. More recently in my flying, I've been required to demonstrate it during certification flight testing. The relationship between Vmc and stall is interesting, as I have been told be my mentors that the aircraft is more safe, if Vmc is close to or at the stall speed. Of course, if the pilot does fly it that slowly on one engine, all the bad things are going to gang up on them. For reference, the certification requirement that most training twins would have to meet reads:
Sec. 23.205

Stalls: critical engine inoperative.

(a) A multiengine airplane must have stall characteristics that prevent unintentional spin entry. This must be shown by performing the maneuver prescribed in paragraph (b) of this section, at the lowest practical altitude, with--
(1) The critical engine inoperative and its propeller in the normal inoperative position ;
(2) Landing gear extended, with the flaps (i) retracted and (ii) extended; and
(3) The remaining engines at full throttle or maximum continuous power.
(b) The maneuver required by paragraph (a) of this section is as follows: Establish a steady, curvilinear turn and, while maintaining a 15 degree bank (1), toward and (2) away from the inoperative engine, steadily increase the angle of attack with the elevator control until an uncontrollable downward pitching motion occurs. In performing this maneuver it must be possible to--
(1) Produce and correct roll by unreversed use of the lateral control until the airplane stalls; and
(2) Recover immediately to full flight control with wings level, from the stalled condition, by normal use of the controls, reducing power on the operating engines if desired without exceeding a 60 degree angle of bank.
The foregoing would have the standard of not requiring unusual pilot skill or attention as expressed elsewhere in the standards. I've flown these stalls in various types from Twin Comanches and DA-42's through to King Air 200's and Twin Otters, and never had a problem. That said, I have taken off with the plan to do it, done it in ideal weather conditions, at altitude, and with no rush or stress.

Hopefully training can be similarly "planned" to be safe. I've done lots in simulators too, and as a result, have reached the conclusion that simulators are excellent procedure training and familiarization tools. The tactile awareness, and sense of "fully committed" the candidate gets from actually flying the maneuver in a plane have their own special value...
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Re: Teaching the VMC demo during ME training

Post by Tylerjohnston »

When I was doing my multi training in the US on the DA42-NG, and we would do multiple Vmc Demos on each local flight. We were also asked to do it on 2/3 stage checks and final checkride. Definitely wouldn't have ever attempted it under 4000'. I don't think you could get the same feeling in a simulator as you do in the actual plane.

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Re: Teaching the VMC demo during ME training

Post by Strega »

Safety concerns

1) Have lots of altitude. I won't do any low airspeed ME practice exercises without at being at or above 4000 ft AGL.

2) Many of the popular trainers have a VMC that is not that much higher than the stall speed. Thrust decreases with altitude which lowers the VMC. The possibility is that the airplane will stall before you see the VMC induced yaw. This obviously very very bad. I deal with this situation by limiting the students rudder travel to approximately half that available by blocking the higher rudder pedal with my foot. This will cause VMC to occur at a higher and safer speed.


Interesting remarks....

How have you arrived at this? is it in the TCCA FIG?
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Last edited by Strega on Sun Feb 14, 2016 10:21 am, edited 1 time in total.
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Re: Teaching the VMC demo during ME training

Post by Rockie »

Strega wrote:
Safety concerns

1) Have lots of altitude. I won't do any low airspeed ME practice exercises without at being at or above 4000 ft AGL.

2) Many of the popular trainers have a VMC that is not that much higher than the stall speed. Thrust decreases with altitude which lowers the VMC. The possibility is that the airplane will stall before you see the VMC induced yaw. This obviously very very bad. I deal with this situation by limiting the students rudder travel to approximately half that available by blocking the higher rudder pedal with my foot. This will cause VMC to occur at a higher and safer speed.


Interesting remarks....

How have arrived at this? is it in the TCCA FIG?
Yes it is on page 29. You know Strega, I don't even do ME training or check guys out on their own airplanes like you do, but out of interest I downloaded the guide for this discussion and gave it a quick read. Perhaps you should too.
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esp803

Re: Teaching the VMC demo during ME training

Post by esp803 »

Big Pistons Forever wrote:I deal with this situation by limiting the students rudder travel to approximately half that available by blocking the higher rudder pedal with my foot.
To say I'd be irate if an instructor limited my controls during any demonstration would be an understatement. There is nothing special about doing a VMC demonstration, and the recovery is pretty simple, simply reduce throttle on the operating engine. You don't have to keep demonstrating it until you are in some sort of spiral dive. Most airplanes have a pretty benign entry into a VMC roll. I'm with PilotDAR on this one.

As for it being in the instructor guide, it suggests using only half deflection, not blocking the controls.
VMC Demonstration
You do not have to conduct a VMC demonstration during training for this rating, yet many instructors do. This can be valuable, but extreme caution must be exercised during the demonstration. Some POHs recommend a procedure for the demonstration. In the absence of a published procedure, instructors may demonstrate this using the following guidelines:
Passengers are not to be carried
Ensure that you have adequate altitude for recovery from an unusual attitude, should one develop.
Both engines must be developing power, one at idle, the other at maximum power.
Allow the aeroplane to decelerate slowly while maintaining directional control.
For an extra safety measure, use only half-rudder input. This will allow the symptoms of VMC to be experienced at a speed higher than the actual VMC.
Recover as soon as directional control cannot be maintained.
Reduce the power on the operating engine, or reduce the pitch attitude, or both.
Failure to recover at the first indication of VMC can lead to a spin.
To me this is the same as demonstrating an inflight shut down, it should be demonstrated in an actual aircraft without artificial limitations, provided you can do it safely.

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Re: Teaching the VMC demo during ME training

Post by Rockie »

esp803 wrote:To say I'd be irate if an instructor limited my controls during any demonstration would be an understatement.
Instructors block controls all the time to prevent students from exceeding predetermined (safe) limits, and if both the student and instructor do their respective actions correctly the student won't even be aware of it. If the student is aware of it, it's probably because the student went too far and the control blockage has done its job. And if any student of mine got angry about something as fundamental as that it would be the immediate end of the lesson and stern lecture in the briefing room about our respective roles would follow.

You - student tasked with learning
Me - instructor tasked with teaching and keeping us alive
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Re: Teaching the VMC demo during ME training

Post by Strega »

A less experienced instructor, who in the interest of safety climbs to a higher altitude for a VMC demonstration, may find that he/she has entered a situation where VMC has decreased to below the stall speed and ends up demonstrating a full-power single-engine stall and spin.
Sound familiar?

That is from the FIG.

"VMC Demonstration
You do not have to conduct a VMC demonstration during training for this rating, yet many instructors do. This can be valuable, but extreme caution must be exercised during the demonstration. Some POHs recommend a procedure for the demonstration. In the absence of a published procedure, instructors may demonstrate this using the following guidelines:
Passengers are not to be carried
Ensure that you have adequate altitude for recovery from an unusual attitude, should one develop.
Both engines must be developing power, one at idle, the other at maximum power.
Allow the aeroplane to decelerate slowly while maintaining directional control.
For an extra safety measure, use only half-rudder input. This will allow the symptoms of VMC to be experienced at a speed higher than the actual VMC.
Recover as soon as directional control cannot be maintained.
Reduce the power on the operating engine, or reduce the pitch attitude, or both.
Failure to recover at the first indication of VMC can lead to a spin."


I dont think it is a good idea to be limiting controls with your foot, or any other means. Note as well it says "you do not have to conduct"
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Re: Teaching the VMC demo during ME training

Post by Rockie »

Strega wrote:I dont think it is a good idea to be limiting controls with your foot, or any other means.
Why not? You prefer getting into a spin while conducting VMC training? I train new pilots on jets and frequently block the controls - that doesn't mean touch them. The only time they touch my hands or feet is when the student put the controls where they shouldn't be and the blockage has done its job in terms of my own awareness and prevention. Fortunately with proper briefing it almost never happens but it pays to be prepared regardless. Learn to do that Strega.

Nice to see you've finally looked at the ME FIG after all the s**t you've flung around about ME training.
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Last edited by Rockie on Sun Feb 14, 2016 10:36 am, edited 1 time in total.
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Re: Teaching the VMC demo during ME training

Post by 5x5 »

The big disconnect on this one for me is why demo it at all? The primary focus of twin engine training is to get the student to understand the affects of a single engine failure on the performance capability of the airplane. There should be a lot of time spent discussing and teaching the theory behind it all. A large component of this is to get them to understand the reason why VMC exists, what will happen should you go there and very strong admonishments not to do so. In real life situations - VMC WILL KILL YOU! We then proceed with all the procedures and decision making training to insure the trainee is not only aware of the risk during single engine operations but is ready to make the hard decisions - i.e. flying it into the ground - if VMC can't be avoided.

So, after all this talk about how deadly VMC is we then say "Really believe what I've just spent all this time trying to impress on you and it's really true, but let's now go out and I'll show you the entry and you'll see how easy it is to recover?" All the reminders in the world about how this demo is done at high altitude, in the best conditions, blah blah blah doesn't change the fact that all the talk about how deadly this is has just gone out the window.

And what is the demo for exactly? In a real life situation, high stress, close to the ground, there is no possible way to recover so you can't argue the demo has any training value for that. Did the student not believe the theory and all the discussion and examples - videos, accident reports, whatever - and they have to see it? I doubt that.

I really can't think of a good reason to demo VMC, and at $5/minute there are much more actually useful things you can be doing in the airplane than discrediting all the respect you've built up for avoiding VMC as Job 1for a piston-twin pilot.
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Re: Teaching the VMC demo during ME training

Post by Strega »

I really can't think of a good reason to demo VMC, and at $5/minute there are much more actually useful things you can be doing in the airplane than discrediting all the respect you've built up for avoiding VMC as Job 1for a piston-twin pilot.
AAAAAAAAA++++++++
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Re: Teaching the VMC demo during ME training

Post by Strega »

Rockie wrote:
Strega wrote:I dont think it is a good idea to be limiting controls with your foot, or any other means.
Why not? You prefer getting into a spin while conducting VMC training? I train new pilots on jets and frequently block the controls - that doesn't mean touch them. The only time they touch my hands or feet is when the student put the controls where they shouldn't be and the blockage has done its job in terms of my own awareness and prevention. Fortunately with proper briefing it almost never happens but it pays to be prepared regardless. Learn to do that Strega.

Nice to see you've finally looked at the ME FIG after all the s**t you've flung around about ME training.

Rockie,

You train with military selected candidates. The realm of training and flying you are used to is orders of magnitude higher in pedigree than 99% of the puppy mill flight schools that are churning out pilots.

If you dont believe me, stop by the nearest flight school in your civvies and as to go for an intro flight,, I think you will be surprised with what you encounter.
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Re: Teaching the VMC demo during ME training

Post by SuperchargedRS »

B208 wrote:....or, do it in a simulator.
:roll:

Seriously, it's like everything in training is too dangerous now days

How about just use common sense during maneuvers vs relegating all this stuff to sims or just not doing it. What's next, not demoing stalls?
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Re: Teaching the VMC demo during ME training

Post by esp803 »

5x5 wrote:In a real life situation, high stress, close to the ground, there is no possible way to recover
Yes, there is. You don't instantly flip on your back when you hit VMC. Hell the last airplane I was doing work with you only need to reduce the good engine by about 5lbs to regain control.

Power to idle, and you're going in straight ahead under control. That is the point. it's better to go in under control straight ahead then to try and save the day and end up on your back. If you're low to the ground at full power and vmc rolling the plane, you've done several things very wrong leading up to this point, might as well know that you can go in under control instead of desperately trying to not crash... as at this point, that is inevitable.

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Re: Teaching the VMC demo during ME training

Post by Rockie »

Strega wrote: The realm of training and flying you are used to is orders of magnitude higher in pedigree than 99% of the puppy mill flight schools that are churning out pilots.
My military days are long past Strega, but if what you say is true that's even more reason to guard the controls.
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Re: Teaching the VMC demo during ME training

Post by 5x5 »

esp803 - you've just described my point even more fully. As I said "We then proceed with all the procedures and decision making training to insure the trainee is not only aware of the risk during single engine operations but is ready to make the hard decisions - i.e. flying it into the ground - if VMC can't be avoided."

The only difference is that I don't want them to get to VMC and then decide to fly it in - that decision should happen once it's clear airspeed is not going to be maintained and it is nearing VMC.

SuperchargedRS - I don't understand the comparison of stall demos to VMC demos in relation to their value in flight training? Plus, I didn't say that VMC demos were dangerous, I simply don't see what purpose they serve, and in fact think they are counter-productive.
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Re: Teaching the VMC demo during ME training

Post by esp803 »

5x5

I do agree that the decision should be made MUCH earlier to fly it in, however I still think that it should be demonstrated that if you do get in that worse case scenario, you can regain control. I'd say most of these (VMC, Engine Shut downs...) it depends on the candidate. Personally, I'm grateful that during all my training (including training received 1000's of hours into my career) that I've had the opportunity to try all of these scenarios in real aircraft. I don't think trying all these scenarios has made me less aware of the dangers of VMC rolls.

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Re: Teaching the VMC demo during ME training

Post by PilotDAR »

And what is the demo for exactly? In a real life situation, high stress, close to the ground, there is no possible way to recover so you can't argue the demo has any training value for that. Did the student not believe the theory and all the discussion and examples - videos, accident reports, whatever - and they have to see it? I doubt that.
I did all my ME training in a 310R back in the day. When it came time for my ride, I went to great effort to seek out an examiner who was familiar with 310s - no point in being examined by an examiner who is not familiar with the type! Happily Seneca College trained on 310s at that time, so I was able to find a 310 capable examiner there.

So there were are in the sky for my ride - I'm nervous, the examiner is relaxed and qualified. "Set up Vmc for me..." So I did, everything slow and easy, and by the book. Zero thrust set, ball in the middle, 5 degrees into the good engine, the whole bit - but darned if I could get that plane to fly straight at the stated Vmca speed, it just slowly went around. No alarm or anything, I could just not keep it straight. I expressed my frustrated defeat at the demonstration to the examiner, I could not keep it straight. He smiled and said: "Don't worry, this model of the 310 will not always fly straight at Vmca, so you did perfectly well." How please was I!

The lesson being, If I wanted to go straight, either speed up, or reduce some power on the good engine. These planes will not suddenly end up on thier back a knot slower than Vmca, they just do not go straight any more. Now I'm not saying that Vmca on one engine is a nice place to be on a dark night overshoot at gross weight, with screaming passengers, but in a planned training environment, if you cannot handle it, some introspection mu=ight be in order.

I'm not an examiner, instructor, nor even a high time multi pilot, but about one tenth of all of my multi flying hours has been deliberately flight testing for Vmca, and stalls following a modification to the plane. I have yet to alarm myself in the least doing that. And yes, I have shut down engines in flight for real, and landed home on one, on two occasions. Again, it was more fear of what I had heard about the situation, that what I was actually experiencing at the time. In the very worst case, you're going in, and you can't prevent it, close the other throttle, and glide in a perfectly stable, symmetrical, controllable plane, and make a decent forced landing out of it!
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Big Pistons Forever
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Re: Teaching the VMC demo during ME training

Post by Big Pistons Forever »

PilotDAR wrote: ..........., but about one tenth of all of my multi flying hours has been deliberately flight testing for Vmca, and stalls following a modification to the plane. I have yet to alarm myself in the least doing that. And yes, I have shut down engines in flight for real, and landed home on one, on two occasions. Again, it was more fear of what I had heard about the situation, that what I was actually experiencing at the time. In the very worst case, you're going in, and you can't prevent it, close the other throttle, and glide in a perfectly stable, symmetrical, controllable plane, and make a decent forced landing out of it!
I think it is important to note that the purpose of Pilot DAR's flight was to determine VMC. The purpose of the VMC demonstration is not to determine VMC it is to teach the student to recognize and recover from an asymmetric thrust induced loss of directional control.

Reducing rudder control provides the exact same training opportunity as reducing speed to the actual VMC, yet increases the safety of this exercise which is why I think it is the best way to perform this exercise.

However regardless of how the maneuver is performed I also think it is important to note and re-emphasize the central point Pilot DAR makes. He doesn't just mess around at low speed in a twin. The exercise is carefully planned, accurately flown and with a clear idea of what should happen and more importantly what should not, and the knowledge and skills to recognize and deal with a deteriorating situation.
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