Courting disaster by "demonstrating" Vmca
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Courting disaster by "demonstrating" Vmca
It is well known that requiring a student to fly a Vmca "demonstration" in a ME aircraft to prove some sort of competency is fraught with danger of mishandling and all the potential for a spin. Colleague described how he was instructing on a C310 where Vmca was being conducted by the student. You know the sort of thing - instructor demonstrates - student practices until certified competent.
A fraction of a second after the nose of the Cesnna 310 began to yaw after the limit of the rudder had been attained, the aircraft went into a vicious spin so quickly that the instructor was completely caught off guard.
After several turns in which considerable altitude was lost, standard recovery action finally took effect and the aircraft bottomed out 1400 ft above terrain leaving three very frightened occupants. However the box marked "VMCA tested" was ticked off of course.
My bet is that scenario has been repeated a thousand times in different light twins, yet from what I can judge the Vmca exercise is a mandatory part of initial multi-engine training. If a fully developed spin is considered an aerobatic manoeuvre and few light twins are certified for aerobatic flight, then surely any manoeuvre such as Vmca that risks an incipient and perhaps a dangerous full spin on a ME aircraft should not be part of a training syllabus.
After all, when flying on one engine in a ME aircraft the student can feel the amount of rudder needed to prevent yaw so why "practice bleeding" just to have the student see how close you can fly to Vmca before flicking inverted? Seems pretty lousy risk management to me.
A fraction of a second after the nose of the Cesnna 310 began to yaw after the limit of the rudder had been attained, the aircraft went into a vicious spin so quickly that the instructor was completely caught off guard.
After several turns in which considerable altitude was lost, standard recovery action finally took effect and the aircraft bottomed out 1400 ft above terrain leaving three very frightened occupants. However the box marked "VMCA tested" was ticked off of course.
My bet is that scenario has been repeated a thousand times in different light twins, yet from what I can judge the Vmca exercise is a mandatory part of initial multi-engine training. If a fully developed spin is considered an aerobatic manoeuvre and few light twins are certified for aerobatic flight, then surely any manoeuvre such as Vmca that risks an incipient and perhaps a dangerous full spin on a ME aircraft should not be part of a training syllabus.
After all, when flying on one engine in a ME aircraft the student can feel the amount of rudder needed to prevent yaw so why "practice bleeding" just to have the student see how close you can fly to Vmca before flicking inverted? Seems pretty lousy risk management to me.
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I wouldn't say, in particlar, that the exercise is to show competence in flying at Vmca - it's more to show why you SHOULDN'T fly at, or even near, Vmca.
It highlights the need for flight at or above "blue line".
I, too, would have "ticked the box VMCA tested" - the lesson had been demonstrated (fairly well, I think).
Now imagine the other scenario - where none of the crew of that aircraft had ever done spin recovery training.
I would also say that ALL aircraft are capable of spinning - they're just certified for doing it intentionally - but that's a product liability factor, not airworthiness.
It highlights the need for flight at or above "blue line".
I, too, would have "ticked the box VMCA tested" - the lesson had been demonstrated (fairly well, I think).
Now imagine the other scenario - where none of the crew of that aircraft had ever done spin recovery training.
I would also say that ALL aircraft are capable of spinning - they're just certified for doing it intentionally - but that's a product liability factor, not airworthiness.
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Is there a requirement for the student to fly at Vmca?
I've only just finished my multi-instructor course, and I don't have my notes to hand, but I seem to recall my instructor on the course teaching me to demonstrate Vmca to the student?
I'm not sure that saying that something "risks an incipient... spin" is justification for not doing it. After all, there is risk of an incipient spin any time you do a stall if the student does not prevent yaw, and this is frequently practiced in aircraft which are not certified for intentional spinning.
Airmanship must surely dictate that this kind of exercise is done at a safe height, though, and also with the instructor having sufficient awareness of the dangers that he prevents a situation developing from which he can not recover. In the example you give, where "the aircraft went into a vicious spin so quickly that the instructor was completely caught off guard", this clearly was not the case - but I'd be willing to bet that the same thing will never happen to this instructor again now that he is aware of the danger!
Thanks for sharing, though - the potential for a spin in this exercise is obvious, but wasn't actually highlighted to me when I did the course. It is definitely something I will watch out for when teaching the multi-engine course though!
FFF
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I've only just finished my multi-instructor course, and I don't have my notes to hand, but I seem to recall my instructor on the course teaching me to demonstrate Vmca to the student?
I'm not sure that saying that something "risks an incipient... spin" is justification for not doing it. After all, there is risk of an incipient spin any time you do a stall if the student does not prevent yaw, and this is frequently practiced in aircraft which are not certified for intentional spinning.
Airmanship must surely dictate that this kind of exercise is done at a safe height, though, and also with the instructor having sufficient awareness of the dangers that he prevents a situation developing from which he can not recover. In the example you give, where "the aircraft went into a vicious spin so quickly that the instructor was completely caught off guard", this clearly was not the case - but I'd be willing to bet that the same thing will never happen to this instructor again now that he is aware of the danger!
Thanks for sharing, though - the potential for a spin in this exercise is obvious, but wasn't actually highlighted to me when I did the course. It is definitely something I will watch out for when teaching the multi-engine course though!
FFF
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Keygrip.
Risking the neck of students (think of the legal ramifications if someone gets killed) to show them why you shouldn't fly at or near Vmca is similar to feathering both engines to show you the dangers if they don't unfeather.
And I know of one idiot who actually did this while he was conducting an instrument rating test on a Duchess. He made the student try to unfeather one engine with minimum loss of height. I recall the adage about old pilots and bold pilots but not too many old and bold pilots. Unfortunately the instructor on the feathered engine instrument rating test himself died a few years later sticking his neck out that little bit too far.
I wouldn't say, in particlar, that the exercise is to show competence in flying at Vmca - it's more to show why you SHOULDN'T fly at, or even near, Vmca
And I know of one idiot who actually did this while he was conducting an instrument rating test on a Duchess. He made the student try to unfeather one engine with minimum loss of height. I recall the adage about old pilots and bold pilots but not too many old and bold pilots. Unfortunately the instructor on the feathered engine instrument rating test himself died a few years later sticking his neck out that little bit too far.
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Unfortunately the instructor on the feathered engine instrument rating test himself died a few years later sticking his neck out that little bit too far
As for the requirements to demonstarte VMCA - just thought I ought to point out the orginator of this thread is in Aus and FFF is in the UK, in case anyone had missed that. Might be differences in the syllabus?
VFE.
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Should we teach - or demonstrate - stalling? spinning? single engine go arounds? PFL's? crosswind landings? unusual attitude recoveries during limited panel instrument flying....they all have inherent dangers if you screw them up.
A lot of the things we demonstrate are to show why you shouldn't do it.
Just simple stalling, for example - we don't teach you to DO it, we teach you what to do if it happens!!
A lot of the things we demonstrate are to show why you shouldn't do it.
Just simple stalling, for example - we don't teach you to DO it, we teach you what to do if it happens!!
Vmca is the min dynamic "recover and maintain S&L constant speed" speed for sudden complete failure with gear up and everything else in t/off position - there's no requirement to even demo this in the UK.
All control demos are steady state:
IMHO fooling around with dynamic failures near to Vmca is asking for trouble and accomplishing nothing -especially if the aircraft is allowed to stall, which must have happened in the situation cited by Centaurus.
BTW, I spend lots of time teaching spinning and aeros in a variety of aircraft but nothing with lumps of mass (ie engines) on the wings; have we anyone here with experience of different spin recoveries for straight winged aircraft with/without wing-mounted stores (or tip tanks)? Most SE aircraft have A<B, it would be interesting to know how spin recoveries change with aircraft when A>B - the info may be useful for recovering a twin.
HFD
All control demos are steady state:
- start at Vyse, gradually throttle back an engine, slow down until a control reaches a limit or Vs+5 reached. Recover by retarding live and lowering the nose before throttling-up both
- as above but at zero thrust
- as above with gear and flap
- as above but at 3-5 deg of bank to live
IMHO fooling around with dynamic failures near to Vmca is asking for trouble and accomplishing nothing -especially if the aircraft is allowed to stall, which must have happened in the situation cited by Centaurus.
BTW, I spend lots of time teaching spinning and aeros in a variety of aircraft but nothing with lumps of mass (ie engines) on the wings; have we anyone here with experience of different spin recoveries for straight winged aircraft with/without wing-mounted stores (or tip tanks)? Most SE aircraft have A<B, it would be interesting to know how spin recoveries change with aircraft when A>B - the info may be useful for recovering a twin.
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A long time ago, as a very low hours PPL holder, when I did all my ME, night and instrument training on a PA39 Twin Comm, most of the time, single engine work was done with simulated zero thrust, but my instructor was very specific about my doing one in flight shut down, a good period of time genuinely on one, and then, the most thought provoking, the restart. We didn't lose any height, but I found my hands had to be flying around all over the cockpit to keep things stable, going in the direction it was meant to be while doing all the other things required for the restart. It was a bit like demeted wall paper hanging, with changes of hands on the yoke, and such like, just to get it started, warmed up safely and then back in balanced flight, but it demonstrated only too clearly that there was a lot of work involved in what in theory sounded very simple to do.
The end of it all, and I was happy that we spent a lot longer than the mandated 5 hours to "do" the ME rating, was that I spent a couple of years doing a lot of hours all over Europe in what was recognised as a very slippery hot ship twin, most of the time single crewed, quite often IFR and IMC. and I thoroughly enjoyed it most of the time, and the few times I didn't it wasn't the fault of the airplane.
What was even more interesting was several years later going over to the States to do a CPL IR ME. I got put with an instructor who probably had about 20 hours total ME time, and at that stage, I had close on 300. It didn't work, the instructor was not comfortable with the airplane, and even less comfortable with the manner in which I was totally comfortable doing things with it that he wasn't. Cue change of instructor, which solved the problem very rapidly.
Making the student demonstrate handling to VMCA is risky, in that the student's responses are likely to be a lot slower than the response needed to keep things in order, especially on the hot ships like the 310 or the PA39, both of which have a "reputation". We certainly did work close to VMCA with simulated zero thrust when doing some of the IR work, to make sure that I was capable of handling the aircraft at the extremes of the envelope, in the same way as I was made to do work close to the VNE end of the speed limitations, to make sure that I knew what to do if I got there by mistake, which it wasn't hard to do on the PA39. It was all about making sure I could recognise the direction of trends, and take positive timely action to change the trend before it went out of limits, which was (in my book) good instructing.
So, I've flown very close to, but not actually at VMCA, and done the same with VNE, for the same reasons, and as far as I'm concerned, that was and is the safest way to deal with it. Anything beyond that should (if possible, and unfortunately on most GA types it's not) be done in a good quality simulator, and by that, I don't mean Microsoft Flight Sim xxxx, as that's not got the necessary fidelity in flight modelling to allow for extreme of the envelope work.
The end of it all, and I was happy that we spent a lot longer than the mandated 5 hours to "do" the ME rating, was that I spent a couple of years doing a lot of hours all over Europe in what was recognised as a very slippery hot ship twin, most of the time single crewed, quite often IFR and IMC. and I thoroughly enjoyed it most of the time, and the few times I didn't it wasn't the fault of the airplane.
What was even more interesting was several years later going over to the States to do a CPL IR ME. I got put with an instructor who probably had about 20 hours total ME time, and at that stage, I had close on 300. It didn't work, the instructor was not comfortable with the airplane, and even less comfortable with the manner in which I was totally comfortable doing things with it that he wasn't. Cue change of instructor, which solved the problem very rapidly.
Making the student demonstrate handling to VMCA is risky, in that the student's responses are likely to be a lot slower than the response needed to keep things in order, especially on the hot ships like the 310 or the PA39, both of which have a "reputation". We certainly did work close to VMCA with simulated zero thrust when doing some of the IR work, to make sure that I was capable of handling the aircraft at the extremes of the envelope, in the same way as I was made to do work close to the VNE end of the speed limitations, to make sure that I knew what to do if I got there by mistake, which it wasn't hard to do on the PA39. It was all about making sure I could recognise the direction of trends, and take positive timely action to change the trend before it went out of limits, which was (in my book) good instructing.
So, I've flown very close to, but not actually at VMCA, and done the same with VNE, for the same reasons, and as far as I'm concerned, that was and is the safest way to deal with it. Anything beyond that should (if possible, and unfortunately on most GA types it's not) be done in a good quality simulator, and by that, I don't mean Microsoft Flight Sim xxxx, as that's not got the necessary fidelity in flight modelling to allow for extreme of the envelope work.
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I seem to sort of remember that Vmca decreases with altitude whilst the indicated stall speed stays the same.
This might explain why I have uncomfortable memories of demonstrating Vmca in a Twin Catastrophy in the Johannesburg GFA one hot summer day.
When the stall speed and Vmca meet or when the aicraft stalls before reaching Vmca things can become interesting in a mild sort of way?
This stimulation of interest becomes exceptionally enthralling if the aircraft in question has tip tanks!
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A very good point Cavorting'
My understanding is also that Vmca decreases with altitude. On my twin oral test the examiner asked if I'd flow at Vmca and at what altitude. When I said yes and quoted the altitude he seemed a little concerned. Thinking that I was about to get my instructor in the do-do I revised the altitude up a little. At this point the examiner became even more concerned and went on the explain that as altitude is increased the Vmca comes closer to the stall speed, which is not recommended! I have no dought that after my test the examiner had a quite work with my instructor
A catch 22 situation if there ever was one!
My understanding is also that Vmca decreases with altitude. On my twin oral test the examiner asked if I'd flow at Vmca and at what altitude. When I said yes and quoted the altitude he seemed a little concerned. Thinking that I was about to get my instructor in the do-do I revised the altitude up a little. At this point the examiner became even more concerned and went on the explain that as altitude is increased the Vmca comes closer to the stall speed, which is not recommended! I have no dought that after my test the examiner had a quite work with my instructor
A catch 22 situation if there ever was one!
Vmc and Vmca decrease with altitude when the thrust from the live engine decreases with altitude - thrust is the cause of all the problems. If you have a superdooperturbocharger thingy then thrust may remain constant up to significant altitudes.
I suspect people here are confusing Vmca with Vmc. Vmc varies with asymm power, flaps, drag, cg position, leg strength - and probably something else that I've forgotten.
... Bottom line is to close the live throttle and lower the nose whenever you reach a control limit or get within 5kts of the stall.
HFD
I suspect people here are confusing Vmca with Vmc. Vmc varies with asymm power, flaps, drag, cg position, leg strength - and probably something else that I've forgotten.
... Bottom line is to close the live throttle and lower the nose whenever you reach a control limit or get within 5kts of the stall.
HFD
Thread Starter
Those that "practice" Vmca flight just to see how far the aircraft will go before it flips inverted at full power on one engine (and instructors who enjoy the challenge - if you can call foolishness a "challenge") are around - could also consider another risky manoeuvre - and that is failing one engine in a light twin during the take off run. We all know it requires instant corrective rudder while simultaneously rapidly closing the live engine throttle.
The danger in this particular manoeuvre lies in the possibility mishandling - or if you like, slow reaction - on the part of the student. In fact the student's corrective action must be perfect and instantaneous at first go in every respect. In that case what is the point of practicing the manoeuvre?
A colleague who remarked somewhat ruefully that his students had run off the side of the runway countless times in his instructional career because of their slow reaction in countering the sudden full power yaw when he cut the mixture to one engine during the take off run. Who knows what side loads the poor nosewheel had applied to it? And was this reported in the maintenance document? I very much doubt it since to inspect for nose gear side strain is an expensive business involving in some cases jacking the aircraft up for retraction tests.
Surely the risks involved and clearly demonstrated warrant calling a halt to this high risk manoevre. If high fidelity simulators were available for these aircraft the high risk manoeuvres in the actual aircraft would be banned from the syllabus.
Deliberately failing one engine on the take off run in a light twin is unwise and some might say poor airmanship. A thorough briefing only is needed - not a real life test of how close the pilot can get to a ground loop without a landing gear strain or collapse?
The danger in this particular manoeuvre lies in the possibility mishandling - or if you like, slow reaction - on the part of the student. In fact the student's corrective action must be perfect and instantaneous at first go in every respect. In that case what is the point of practicing the manoeuvre?
A colleague who remarked somewhat ruefully that his students had run off the side of the runway countless times in his instructional career because of their slow reaction in countering the sudden full power yaw when he cut the mixture to one engine during the take off run. Who knows what side loads the poor nosewheel had applied to it? And was this reported in the maintenance document? I very much doubt it since to inspect for nose gear side strain is an expensive business involving in some cases jacking the aircraft up for retraction tests.
Surely the risks involved and clearly demonstrated warrant calling a halt to this high risk manoevre. If high fidelity simulators were available for these aircraft the high risk manoeuvres in the actual aircraft would be banned from the syllabus.
Deliberately failing one engine on the take off run in a light twin is unwise and some might say poor airmanship. A thorough briefing only is needed - not a real life test of how close the pilot can get to a ground loop without a landing gear strain or collapse?
Last edited by Centaurus; 20th May 2006 at 03:57.
I could not agree more Centaurus!
This (simulated engine failure on take-off) is supposedly a mandatory item on MEPL tests in the UK but is not something that I do - it's a bit like practise die'ing (sp?). If an engine genuinely fails during the take-off roll then any damage is a consequence of the failure and is in the "sh1t happens" category. The training risk can be totally removed by dealing with this by discussion.
Twins seem to crash for a variety of reasons: I believe there was a Seneca fatal in the US a couple of years ago where part of the (male) pilot's anatomy was found in the (female) pax's mouth?
Cause or effect?
Perhaps this should be a test item too
HFD
This (simulated engine failure on take-off) is supposedly a mandatory item on MEPL tests in the UK but is not something that I do - it's a bit like practise die'ing (sp?). If an engine genuinely fails during the take-off roll then any damage is a consequence of the failure and is in the "sh1t happens" category. The training risk can be totally removed by dealing with this by discussion.
Twins seem to crash for a variety of reasons: I believe there was a Seneca fatal in the US a couple of years ago where part of the (male) pilot's anatomy was found in the (female) pax's mouth?
Cause or effect?
Perhaps this should be a test item too
HFD
Last edited by hugh flung_dung; 21st May 2006 at 10:35.
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Without really raiding my notes I seem to remember that Vmca is quite specific to each aircraft and that it is established under a particular set of circumstances.
Is it defined as the speed at which:
1. At sea level.
2. Flaps in the take off position.
3. Gear down.
4. Max continuous thrust set.
5. Critical engine propellor windmilling.
6. C of G in the aft position.
7. Aircraft at max all up weight.
Control of the aircraft cannot be maintained with full opposite rudder deflection.
It is a very specific speed which is established under the worst go round conditions. If demonstrated at safe height the excercise provides a useful illustration to the student that there is a speed below which he cannot control the airrcaft in the event of assymetric flight.
I've probably forgotten something here but that's the gist of it is from what I remember back in the old days of twin training. It's a useful excercise which illustrates what can happen with slack attitude and speed control in such situations as engine failure after take off or single engined go round.
Last edited by cavortingcheetah; 21st May 2006 at 14:56.
Thread Starter
If demonstrated at safe height the excercise provides a useful illustration to the student that there is a speed below which he cannot control the airrcaft in the event of assymetric flight
Meanwhile it would seem prudent for ME instructors to stay away from Vmc especially as normal asymmetric flight requires a fair amount of corrective rudder making it obvious to a student that running out of rudder is not a good thing.
cavortingcheetah:
6 out of 7
the gear is up. I assume there should not be so many not's there either
FWIW a heading change of up to 20deg is allowed but no loss of height, rudder force should be <770N and roll control force should be <220N with a yoke. BUT, as I said before, Vmca is a DYNAMIC situation involving "sudden complete failure of the critical engine" and has no practical relevance to flight instruction.
Centaurus:
Demos of the need to feather, raise flap, decrease drag and add small bank angle are an essential part of the training and this requires flight close to Vmc but must be stopped when a control reaches a limit or Vs+5 is reached, as I've said before. This achieves the aim of the exercise without introducing risk.
The real safety issue here is stalling when asymmetric, rather than Vmc
The UK syllabus (complete with typos!) is available here: http://www.caa.co.uk/docs/33/CAP601.PDF
HFD
6 out of 7
the gear is up. I assume there should not be so many not's there either FWIW a heading change of up to 20deg is allowed but no loss of height, rudder force should be <770N and roll control force should be <220N with a yoke. BUT, as I said before, Vmca is a DYNAMIC situation involving "sudden complete failure of the critical engine" and has no practical relevance to flight instruction.
Centaurus:
Demos of the need to feather, raise flap, decrease drag and add small bank angle are an essential part of the training and this requires flight close to Vmc but must be stopped when a control reaches a limit or Vs+5 is reached, as I've said before. This achieves the aim of the exercise without introducing risk.
The real safety issue here is stalling when asymmetric, rather than Vmc
The UK syllabus (complete with typos!) is available here: http://www.caa.co.uk/docs/33/CAP601.PDF
HFD
Last edited by hugh flung_dung; 21st May 2006 at 13:40.
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Some thoughts ..
(a) Vmca normally is a work up for static values and then checked to make sure that the dynamic failure is not more critical
(b) the sea level value is an extrapolation from the altitude work
(c) playing with low speed asymmetric thrust ... ie near stall ... is silly at best for non TP folk .. so, for normally aspirated birds, he who plays with this at altitude is even sillier ..
(d) for most light twins there is no performance left to play with at or about Vmca so the pilot ought not to be anywhere near Vmca in most Types for any normal or routine OEI situation
(e) "Vmca" demonstrations have very little to do with Vmca as such although they provide an exposure to the static Vmca situation
(f) real world Vmca is very much bank angle dependent. Generally it may be assumed that the book figure is based on 5 degree bank (only because the test is not allowed to use more bank ..). If one doesn't use this figure the Vmca goes up .. and, if the bank is allowed to go the wrong way, it goes up rapidly ..
(g) if you must expose the student to the yawing problem .. rather than just discussing it over coffee, then consider arbitrarily introducing a conservative delta by having the instructor restrict rudder travel. A colleague once had to do a lightie endorsement to renew an instrument rating .. the instructor thought it appropriate to have a look at Vmca .. my colleague (who knew lots about Vmca in any case) thought otherwise .. so he restricted rudder travel himself .. confused the instructor greatly ... but got my colleague the tick in the box without exposing himself to fearful risk.
At the end of the day, Vmca is a line in the sand certification boundary condition and has little to do with real world flying .. so, why go there ? .. it's a bit like playing marbles on the middle of a busy road ..
(a) Vmca normally is a work up for static values and then checked to make sure that the dynamic failure is not more critical
(b) the sea level value is an extrapolation from the altitude work
(c) playing with low speed asymmetric thrust ... ie near stall ... is silly at best for non TP folk .. so, for normally aspirated birds, he who plays with this at altitude is even sillier ..
(d) for most light twins there is no performance left to play with at or about Vmca so the pilot ought not to be anywhere near Vmca in most Types for any normal or routine OEI situation
(e) "Vmca" demonstrations have very little to do with Vmca as such although they provide an exposure to the static Vmca situation
(f) real world Vmca is very much bank angle dependent. Generally it may be assumed that the book figure is based on 5 degree bank (only because the test is not allowed to use more bank ..). If one doesn't use this figure the Vmca goes up .. and, if the bank is allowed to go the wrong way, it goes up rapidly ..
(g) if you must expose the student to the yawing problem .. rather than just discussing it over coffee, then consider arbitrarily introducing a conservative delta by having the instructor restrict rudder travel. A colleague once had to do a lightie endorsement to renew an instrument rating .. the instructor thought it appropriate to have a look at Vmca .. my colleague (who knew lots about Vmca in any case) thought otherwise .. so he restricted rudder travel himself .. confused the instructor greatly ... but got my colleague the tick in the box without exposing himself to fearful risk.
At the end of the day, Vmca is a line in the sand certification boundary condition and has little to do with real world flying .. so, why go there ? .. it's a bit like playing marbles on the middle of a busy road ..
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May I relate an example of what you're all talking about?
I had a student who got a little slow on his demonstrated (simulated) asymmetric approach to land. Since it was a competency check I allowed him to do so. It's not every day someone tries to kill me, so I watched with great interest.
At about 200 feet he realised he was not on profile, and slow as well. So he added significant power to the live engine. Regrettably, and not unexpectedly, he added only a small amount of rudder, and that after the power increase.
What followed was a textbook approach to Vmc, but he did not recognise it, the aircraft continuing to yaw and roll for long enough for him to know how serious the situation was. (No flaming please - yes I did immediately take over, and no we did not get anywhere near the actual Vmc of the day, although the student's lack of rudder input made it look like we did.)
This student had followed the standard course of training, which included several approaches to a situation resembling Vmca. He was quite current, and primed for the test. He had excellent ground knowledge of Vmca, having discussed the theory & effects in class. Upon encountering unexpected yaw and roll on an asymmetric approach, he froze.
I suspect that he is not alone, and that the relatively few Vmca fatalities have more to do with Lycoming reliability than good training.
(Closing note - in this particular individual's case, his asym approaches are now invariably on or above profile and 5kts above normal approach speed. So he at least has learned something quite valuable.)
I had a student who got a little slow on his demonstrated (simulated) asymmetric approach to land. Since it was a competency check I allowed him to do so. It's not every day someone tries to kill me, so I watched with great interest.
At about 200 feet he realised he was not on profile, and slow as well. So he added significant power to the live engine. Regrettably, and not unexpectedly, he added only a small amount of rudder, and that after the power increase.
What followed was a textbook approach to Vmc, but he did not recognise it, the aircraft continuing to yaw and roll for long enough for him to know how serious the situation was. (No flaming please - yes I did immediately take over, and no we did not get anywhere near the actual Vmc of the day, although the student's lack of rudder input made it look like we did.)
This student had followed the standard course of training, which included several approaches to a situation resembling Vmca. He was quite current, and primed for the test. He had excellent ground knowledge of Vmca, having discussed the theory & effects in class. Upon encountering unexpected yaw and roll on an asymmetric approach, he froze.
I suspect that he is not alone, and that the relatively few Vmca fatalities have more to do with Lycoming reliability than good training.
(Closing note - in this particular individual's case, his asym approaches are now invariably on or above profile and 5kts above normal approach speed. So he at least has learned something quite valuable.)