What is the safe ejection mechanism for helicopters?

As Sophia said, there really isn't one. Helicopters can autorotate, which is what you want to do. read more

Helicopter seats are different from fighter Jet seats as they need to absorb vertical accelerations too , seats take mostly forward forces in choppers there is no space above for an ejection system with rotor blade spinning at high speeds,.Ejection seat is not a common mechanism seen in Helicopter s How ever Ka50 Black Shark is the world's first operational helicopter with a rescue ejection system. read more

Various ejection seats. In aircraft, an ejection seat or ejector seat is a system designed to rescue the pilot or other crew of an aircraft (usually military) in an emergency. In most designs, the seat is propelled out of the aircraft by an explosive charge or rocket motor, carrying the pilot with it. read more

An ejection seat is comfortable and adjustable seat for the pilot of a fighter aircraft. Unlike other seats, this is never fixed on to the aircraft floor. Rather, it is mounted on a rail on which it can slide up and down. read more