Whats the differnce between turning the fuel off and cutting the mixture?
If you turn the fuel off it takes a finite amount of time for the fuel in the lines to be used up and the engine to stop, and when you turn it back on again there will be another delay before the engine restarts as fuel is pumped back into the carburettor (or fuel injection plumbing)
If you cut the mixture the engine will stop producing power immediately, and when you put the mixture back to rich the engine will start producing power immediately.
Big difference.
Usually the aircraft folder of a piece of paper or something handy was used to cover
I do this for two reasons: First to help the student focus on the aircraft performance for their decisions, not on the position of the levers. Second, to signal that this is an intentional failure, and power will be available immediately if needed.
I use throttle for the initial engine failure practice, Vmca demo (although there are those who say we shouldn't be doing that either), and low level engine failures. I do not initiate any engine failures below 300 ft AGL - ever - and usually use a higher minimum height depending on the situation.
I use mixture for all other engine failures because the restoration of power is immediate, and the engine manufacturers' published data says it's less stressful for the engine than the pumping stresses which happen when you close the throttle.
But then I learnt my META from the same bloke that the Dr refers to. And he's bloody good.
If my closing the mixture is a problem for anyone, then I'm very happy if we don't fly together.