Originally Posted by
JamesNoBrakes
As you get more high performance, away from pistons, you get big massive propellers that can move a lot of air and move the airplane faster. It's a double-edged sword. It means when you have an engine failure, if it doesn't feather, it affects control significantly more, as in having a great big drag source. These will slow down fast, compounded by not pushing the nose down. Keeping one of these in a climb attitude and with an unfeathered failed engine is going to likely Vmc roll it every time. It's on the before takeoff checklist to feather the engines on the ground and bring them out with the manual feather to make sure this is possible in the air and the first cockpit item besides control for an engine failure is to verify that it's feathered and manually feather if it hasn't. You can't screw around with that in these planes, they slow down quickly. It's rare for the autofeather to fail, but it has happened.
I wouldn't call it exactly rare, but that depends on the type I guess. Manual Fx is more reliable than auto, but you have to remember to do it, and quickly.
Spot on that twin turboprops are susceptible to Vmc. In addition to the drag created by a large unfeathered prop, you also have a very powerful motor at full power on the other side. It can easily get out of hand, and more quickly than a piston twin. IMO survival in turboprops requires that you plan for, expect, and mentally rehearse the engine failure prior to each T/O.