I think the best advice in a light twin, is not to turn into a dead engine if at all possible, this is what I was taught for my ME rating. Of course if you're on an object clearance departure and you have no choice, then of course you must turn into a dead engine. It is possible, but you just have to be very aware of your airspeed, and how Vmc changes with various flight attitudes and I imagine that in an already underperforming twin, the tendancy to let speed decay trying to maintain altitude will be rather high.
The effects of speed dropping below Vmc are quite dramatic. For the FAA ME rating you have to give a Vmc demo to the examiner, which consists of flying straight and level on one engine [ie. 5° bank], then pulling the nose up and letting the airspeed decay, maintaining full power on the critical engine [if applicable]. In the region of Vmc at ["Actual" Vmc], you basically loose control, the nose suddenly yaws away from the good engine fairly quickly even with full oposite rudder input. The only way recover is to increase airspeed, & / or reduce power on the good engine...no other options.... Not good if you're close to the ground.
Vmc is a complicated subject, I remember being grilled on it by the examiner for the oral exam, though I must admit I probably couldn't recite all the forces involved now. It varies with angle of bank, whether your gear is down or not, whether the flaps are down or not, altitude, etc etc. The best thing is to keep well above it, especially close to the ground or in the region known as 'Coffin Corner' where stall speed and Vmc co-incide.
I would still be unwilling to turn into a dead engine unless I had to !
Cheers
EA
