The helicopter took off and entered a hover in ground effect before a climbing turn to the left was initiated from approximately 10 feet above ground level(agl). Immediately the turn was commenced the helicopter started to lose mainrotor rpm. The terrain drops away from the heli-pad and the helicopter was now 35 to 40 feet agl. The pilot attempted to regain rotor rpm by lowering the collective and increasing throttle, however, RPM was not regained and the helicopter continued in the descent until ground impact. The pilot was interviewed by an Examiner of Airmen who was of the opinion that the symptoms described by the pilot indicated that the mainrotor was overpitched during the climbing turn.
