The myth goes that if a helicopter engine dies, it will drop like a rock and crash. This couldn’t be further from the truth.
Daven Hiskey via Today I Found Out:
In fact, you have a better chance at surviving in a helicopter when the engine fails than you do in an airplane. Helicopters are designed specifically to allow pilots to have a reasonable chance of landing them safely in the case where the engine stops working during flight, often with no damage at all. They accomplish this via autorotation of the main rotor blades.