I know your question is 2 years old, but the answer is that it's safer for the twin-engined helicopter to carry out a lift while maintaining a steady forward speed. That way, if one engine fails, the remaining engine will open up and provide sufficient power to continue the mission. If the lift was done with the helicopter in a hover, and an engine fails, the transition of power from both engines to the remaining good engine could cause a moment of instability for the helicopter. If someone is on the end of the winch when this happens, it could cause them injury.

its an excerscise

@@RePlayBoy101 The maneuver is one of necessity of safety.

The forward motion provides more lift. And less engine power is required.

@@harlingthetrucker9971 thankss