I think the OP is referring to Category A operations in twin engined helicopters.
Essentially if one engine fails at any time after the start of takeoff the helicopter can either return to the point of takeoff or safely climb away. In the case of a confined area or elevated helipad the aircraft will fly 300ft backwards to the Take Off Decision Point (TDP) at height of about 100ft, before accelerating forward and climbing away.
In open airfields, and in single engined helicopters, a forwards takeoff profile is normally performed.