Vsse

flight instructor · Post by **flight instructor** » Mon Dec 10, 2007 7:36 pm

.....who in hell do you think you are telling me I have never practiced that exercise ....

So you have practised this exercise yes or not? I am confused with your reply.

I know who you are, I respect you experience, I admire you.

But if you tell me I am wrong when I am right, then I will stand up in front of you even if your name is . Yeager.

Now if you ask me to be polite towards you and don' t let you loose face because of your experience, well I can understand.

flight instructor · Post by **flight instructor** » Mon Dec 10, 2007 7:42 pm

Exactly what is the purpose of a Vmc demo? Do multi-engine students
doubt so strongly that Vmc exists, that they need a convincing demo?
Is Vmc really that hard to comprehend?!

That' s not the point. Nobody doubt that VMC exist. That ' s to practise, final point.

Nobody doubt an aiplane can fly right? We still have to practise to learn how to fly...

Yes Hedley I know you too are an experienced pilot and instructor.

Hedley · Post by **Hedley** » Mon Dec 10, 2007 7:47 pm

Just to point out one little detail ....

The stick & rudder skills of most low-time pilots (which includes
instructors) is atrocious. Cessna 172's - the most docile creatures
on the planet - are frequently destroyed during cross-wind (gasp!)
landings. I am told that no less than the vaunted Seneca College
has a 5 knot (no typo, FIVE KNOT) maximum allowed crosswind
component for their students (!) which I sincerely hope is not true.

Hardly anyone is up for even the tamest of taildraggers. Cubs,
champs and chiefs are all considered wild, snorting bucking
stallions by today's pilots (guffaw).

The most basic of aerobatics is considered "black art". A
simple wingover, chandelle, aileron roll, 1/2 cuban-8 or
hammerhead is considered an extraordinary maneuver.

And you want these guys doing Vmc demos? Lord, why?

mcrit · Post by **mcrit** » Mon Dec 10, 2007 7:52 pm

Doing an actual Vmc demo (ie critical engine windmilling, good engine wide open, and reducing the speed until you can't control yaw) is really cutting into the safety margins. I have no doubt that there are people who do Vmc demos on a regular basis, and that they can do them safely provided nothing goes wrong. Where things start to get interesting is when some other factor unexpectedly comes into play at a critical time. Things like a burst of turbulence, mechanical failure, sweaty hands, over tight throttle friction lock, student brain farts, and general distractions can all lead to the a/c stalling before yaw has been controlled. Now you are into a spin, from which recovery is far from certain.
A Vmc demo is not certain death, but it is working without a net. I am certain that 9999 out of 10000 Vmc demos go off without a hitch, its just that 1 that you have to worry about.

Isis · Post by **Isis** » Mon Dec 10, 2007 7:55 pm

Mr. Hedley, I will attempt to answer your question.

We teach slow flight so that they can avoid stalls, we teach stalls so that they can avoid spins, and we teach spin recovery so that heaven forbid if it should happen they can recognise and recover safely.

We'd be remiss not to include Vmc demonstrations for the very same reason.

- Isis

Where'd who go? · Post by **Where'd who go?** » Mon Dec 10, 2007 7:58 pm

Hell, I'm just going to call in sick tomorrow. This is too frightening.

WWG?

Cat Driver · Post by **Cat Driver** » Mon Dec 10, 2007 7:59 pm

So you have practised this exercise yes or not? I am confused with your reply.

Yes, many times....

In fact I had exactly this same discussion with the Dutch CAA inspector who was sent to do the check rides for the issuance of type ratings on the Cat in Holland a few years ago.

He was adamant that the airplane must be flown down to VMC on one engine at full power on the operating engine.

So I said here is what we will do, you demonstrate to me how to do it...if you are successful and can reduce speed to the published indicated airspeed and still recover without losing control I will hand in my authorization to teach in Holland and go back to Canada.

I had him climb to six thousand feet above the ground before beginning the demo.

We had an understanding that if it started to become unmanageable I would take control and recover.

I was calling out airspeed as he slowly reduced to VMC...at three Knots above VMC I said don't go any further..he did and the loss of control was so sudden he had no idea that I had taken control.

It wasen't pretty we lost over 2500 feet and the airplane had entered a full blown spin before I could stop it.

He was white as a sheet and said lets go back to the airport, I said no we are going to do some water training and then we will go back.

Anyhow we ended up the best of friends and there was never any problem when he did the check rides and ended up giving me my own check authority to issue type ratings.

There are a whole lot of airplanes out there that are just to critical at VMC to deliberately play in that region of flight.

Safety is never letting the thing get in that region of flight.

flight instructor · Post by **flight instructor** » Mon Dec 10, 2007 8:06 pm

Doing an actual Vmc demo (ie critical engine windmilling, good engine wide open, and reducing the speed until you can't control yaw) is really cutting into the safety margins. I have no doubt that there are people who do Vmc demos on a regular basis, and that they can do them safely provided nothing goes wrong. Where things start to get interesting is when some other factor unexpectedly comes into play at a critical time. Things like a burst of turbulence, mechanical failure, sweaty hands, over tight throttle friction lock, student brain farts, and general distractions can all lead to the a/c stalling before yaw has been controlled. Now you are into a spin, from which recovery is far from certain.
A Vmc demo is not certain death, but it is working without a net. I am certain that 9999 out of 10000 Vmc demos go off without a hitch, its just that 1 that you have to worry about.

What is very interesting in this statment is that you can replace vmc demo at the begining of the text by: spin, full feather shut down, stall, unusual attitude, spiral dive... and the statment remains true...

I have done a lot of VMC demo even with turbulence it doesn t change the exercise. When you say a mechanical failure could you give, please an example?
Over tight throttle friction lock? Don' t push too much it' s becoming funny

Where'd who go? · Post by **Where'd who go?** » Mon Dec 10, 2007 8:06 pm

Hi Cat,

Why are these aeroplanes spinning when VMC is (often) well above stall speed?

WWG?

Cat Driver · Post by **Cat Driver** » Mon Dec 10, 2007 8:13 pm

Hi Cat,

Why are these aeroplanes spinning when VMC is (often) well above stall speed?

WWG?

Hell, I'm just going to call in sick tomorrow. This is too frightening.

WWG?

I wouldn't want to frighten you by explaining it.

Ask Hedley, I'm tired of this crap.

Where'd who go? · Post by **Where'd who go?** » Mon Dec 10, 2007 8:19 pm

Sorry you feel that way Cat.

Ok Hedley, let'r rip. (please)

WWG?

Pugster · Post by **Pugster** » Mon Dec 10, 2007 8:43 pm

I'm out as well on this one.

Guys, if you want to do VMC demos, knock your socks off.

I however, as the experienced pilots who chimed in as well, would not recommend it. Take that advice as you will. Oh - and your previous statement of:

This is the deal in aviation: let nothing get away on you.

Trust me - lots will get away on you - it's what you do when it does that counts. I've seen guys with excellent hands and feet, loads of experience, and typically good judgement make some doozies (myself included - but I'm working on it

. But thank you for the summation of what aviation is all about...I really wasn't clear, and your brief description of what goes on should provide for a good discussion tomorrow while I'm flying over you at FL370.

So that is why VMC demonstrations are not a good idea - because if it does get away on you, there's a good chance that you won't be around to talk about it. In all of the exercises you compare it to there is a much larger error margin and the results of a major F-up are easier to deal with. If the comments against seem a bit charged it's just because nobody wants to see an instructor put him or herself at a greater level of risk than necessary. Especially for an exercise with (IMHO) little real value to the student.

Ok, I'm done now. Pugster OUT.

Isis · Post by **Isis** » Mon Dec 10, 2007 9:07 pm

You did not read (or understand) my post. I do not flirt with fate or laugh in the face of danger. My SIMULATION/DEMONSTRATION is safe. I agree there are risks involved but no more than any other air exercise taught for the multi conversion.

We'll just have to agree to disagree.

- Isis

Cat Driver · Post by **Cat Driver** » Mon Dec 10, 2007 9:40 pm

Evenin Isis:

Can I with all due respect to you explain why I do some things such as the following?

I have a couple of points I'd like to make. First it is very rare (if not unheard of) for me to have an opportunity to correct an inadvertent typo by Mr. Driver. Let's all remind ourselves of the conditions under which Vmc is determined:

... one engine becomming inoperative and windmilling - not zero thrust as was previously stated.

When posting here I usually don't bother to explain things in the clinical wording that many flight instructors are programmed to think in...so allow me to very gently explain why I use zero thrust..instead of a windmilling prop.

Generally loss of control during an engine failure does not occur immediately after the engine fails, it is usually after the prop has been feathered.

When I set zero thrust it is one more small asset to more closely mimic the rate of control loss, time wise, and it just exactly like a feathered engine.

Rather than a faster rate of speed decay as will be experienced with a windmilling prop.( which by its extra drag will exacerbate the loss of directional control. )

My methods may not fit the same criteria that an instructor teaching on small twin engine aircraft may be taught to use....but my methods do fit the real world of how airplanes drift into out of control situations.

So please do not think that I am unfamiliar with the physics and aerodynamics of how aircraft either fixed or rotary wing fly by parsing my comments here on Avcanada.....which unfortunately I quite often don't take the time to super check for being 100% correct.

I like to think that I can recognize pilots on this forum that I would be pleased to fly with from reading their posts...and generally I am fairly close.

From what I have read of your posts if you are ever out this way and would like to wring out the new Husky that I should have here in the new year I can afford the time and fuel if you would like to go flying with me.

. E.

mcrit · Post by **mcrit** » Mon Dec 10, 2007 9:50 pm

FI:
What this comes down to is risk management. In this process each person sets their own personal limits. I always look at how many things have to go wrong (and how likely they are to take place) in order for me to get killed. In spinning a training a/c the only things that are going to kill me have a low probability of occuring (major mechanical failure, student freezing at the controls). Same thing with a full feather demo (even if the running engine cacks out I've got 7000' of altitude to get the other started again, and if that doesn't work I'm over an airport). If you are touring around at Vmc in most light twins you only need one of a very many things to go wrong to put you in an unrecoverable situation. The reason being that Vmc and the Stall speed are very close (as in 1 knot on some a/c). If you stall a twin with power on one side it's going to spin, and it's a good bet that it's not coming out (NASA did some tests on the matter).
I know the over tight friction lock sounds far fetched, but I had it happen. I was doing some power on spins with a smaller student. Somehow on the 3rd spin the throttle friction lock got torqued down quite tightly. The student's hands were sweaty and on her first attempt to retard the throttle her hand slipped off. This delayed the recovery. Now, what would have happened if that had been a Vmc demo?

Isis · Post by **Isis** » Mon Dec 10, 2007 9:56 pm

*smiles* Mr. ., I quoted your comments a little tongue in cheek. I have no doubt that it was intentional and am a little curious by your findings. Thank you for your clarifications.

As a windmilling prop tends to increase Vmc, I find the rate of speed loss is higher with it windmilling rather than the zero thrust setting (isn't this one of the reasons we feather? To eliminate drag?). My students even notice that while doing their cause checks the quicker they make the decision to feather, the easier the plane is to fly (once the zero thrust is set).

Based on these experiences, I questioned your comments. However, after clarification, I can understand why in larger aircraft you would opt for the zero thrust.

We have had many a good conversations, Sir, and I will always consider myself a student. However, I also feel I am a good instructor and do love what I do. I understand your frustrations with the flight training industry in Canada, but please do not paint me with the same brush.

I accept your offer of flight and return one to you aswell. Should the Greyhounds ever catch your fancy, I'd be more than thrilled to take ya flying in a Czech-mobile.

- Isis

Isis · Post by **Isis** » Mon Dec 10, 2007 10:04 pm

mcrit wrote:... If you are touring around at Vmc in most light twins...

I don't think anyone said anything about 'touring around'. In fact, I clearly stated that we SIMULATED it (ie. min 15 kts above Vmc) and DEMO'd it once - no practicing.

mcrit wrote:... Now, what would have happened if that had been a Vmc demo?

I would have taken control and recovered. What did you do, watch?

- Isis

trey kule · Post by **trey kule** » Mon Dec 10, 2007 10:13 pm

What does a twin go for these days....about $5.00 a minute?

Despite the references to the US system, this is an unnecessary exercise.
I think the problem is that it has become very emotional . Those of you who insist on doing it seem to think it perfectly safe. Some of us dont

Maybe we should leave it at that.

Cat Driver · Post by **Cat Driver** » Mon Dec 10, 2007 10:14 pm

For some reason I'm sitting here on the computer watching Rita McNeil's Xmas program and surfing this forum and got stuck in this discussion.

MCRIT when I was reading your excellent comments I drifted back in time and got thinking of some of the engine failures I had over the years....and like all of life's experiences the most vivid memory is of an engine failure in a DC3 one night and looking back in the dimly moon lit night at the trail of black smoke against the white snow and ice below me, that I was leaving behind when a passenger came up front to ask me if I knew we had an engine on fire.

What had happened was we had a bad oil leak from a cracked cylinder that had not shown up on the instruments nor was there any indication that something was going terribly wrong from the sound of the engines.

To make a long story short it quickly went to hell and I feathered it and flew 275 N.M. to Resolute Bay.

It was a routine single engine shut down and flight on one engine that night but that picture of the long black smoke trail in the dim white Arctic night is as clear as if it were just an hour ago.

Was I afraid? yes, in those situations there is always that subliminal feeling of fear inside you, but dealing with the situation and planning ahead with the intention of not crashing short of your destination keeps one to busy to allow fear to overcome doing what you must do to keep it in the air.

Isis · Post by **Isis** » Mon Dec 10, 2007 10:22 pm

Wow! That must have been a sight (and experience) indeed. Almost an eerie pretty.
I don't doubt your experiences at all. In fact, keep havin' em, and sharin' em, so maybe I can learn from them. *thinking of the old saying*

When I recommend someone for the multi-rating, safety is the number one thing on my mind. Do not presume otherwise, Mr. Mcrit.

So yes, let's agree to disagree and I will continue ensuring my students are safe multi-engine pilots.

- Isis

Cat Driver · Post by **Cat Driver** » Mon Dec 10, 2007 10:26 pm

Wow! That must have been a sight (and experience) indeed. Almost an eerie pretty.

It truly was....eerie pretty.

That was a long time ago...1970...

Christ I must be getting old.

Isis, here is a picture of the last DC3 I flew, it is Fifi Kate from the TV Series Band of Brothers..that was taken in Holland in 2005.

http://i43.photobucket.com/albums/e353/ ... 0045-1.jpg

THEICEMAN · Post by **THEICEMAN** » Tue Dec 11, 2007 10:00 am

Enough...white flag! This is getting stupid...
Cat, if you feel that VMC demos should not be done...fine!

But tell me this, if most schools in Canada re giving VMC demos....are they all wrong?
I am not arguing with you on this one, I just want to know where you stand?

Hardly anyone is up for even the tamest of taildraggers. Cubs,
champs and chiefs are all considered wild, snorting bucking
stallions by today's pilots (guffaw).

You will be surprised....many of my fellow younger pilots, are trying to rent PA-18s.
The question should be, control zone student versus MF/ATF student. At least where I am, most control zone students are afraid of crosswind landings!

I love the supercub! Boring as hell duing cuise, but the T.O/landing performance is incredible......

Cat Driver · Post by **Cat Driver** » Tue Dec 11, 2007 11:00 am

I am not arguing with you on this one, I just want to know where you stand?

From reading your posts my position is I would not want you for a student......

You can lead a horse to water..........

trey kule · Post by **trey kule** » Tue Dec 11, 2007 12:57 pm

Isis wrote:

We teach slow flight so that they can avoid stalls,

Really? Thats it? You teach slow flight so as to avoid stalls!

I read so many posts here that makes me shiver. I really feel for the poor trusting students who are learning to do a multi-engine rating from some of the posters here....

THEICEMAN · Post by **THEICEMAN** » Tue Dec 11, 2007 1:29 pm

Cat Driver wrote:
I am not arguing with you on this one, I just want to know where you stand?
From reading your posts my position is I would not want you for a student......

You can lead a horse to water..........

Oh wow...i'm impressed! So much you can tell just from post?

Just answer the question, without rhetoric please!

You can lead a horse to water..........

I don't know where you come from, but you can cross a stream with a horse!