Background
Prior to the instructional helicopter flight, the flight instructor and the student pilot discussed a loss of engine power during takeoff. The student pilot, who had not previously performed the maneuver, believed the flight instructor was going to demonstrate it.
Flight
During the flight, while the helicopter was climbing through 400-500 feet, the flight instructor advised the student of the pending simulated engine failure and rolled down the throttle. The helicopter commenced an autorotation.
Miscommunication
At this point, a miscommunication occurred: the flight instructor thought the student pilot was at the controls, while the student pilot thought the flight instructor was at the controls.
Autorotation
During the autorotation, when the helicopter appeared to be headed for some trees, the collective was raised to extend the glide. However, the rotor rpm was decreasing and the forward airspeed had also slowed. The helicopter cleared the trees, but at 60 feet above the ground, the rotor rpm was below the power-off range.
Recovery and Impact
The flight instructor then got on the controls, lowered the collective, rolled on the throttle, and flared the helicopter. The helicopter continued its descent, the tail hit the ground, and the helicopter impacted the ground in a level attitude, then rolled over.