Robinson R44 Ii crash near Tunica, MS, United States

The flight instructor and the student pilot were practicing hovering autorotation maneuvers in a helicopter. Following a successful autorotation, and while the helicopter was on the ground with the collective pitch control fully lowered, the pilot told the student, "let's do another one." The flight instructor planned to remind the student pilot to center the anti-torque pedals, as some right pedal was still applied following the preceding autorotation. Before he could do so, the student pilot rapidly increased the engine throttle and the helicopter began yawing to the right. In order to keep the helicopter from sliding along the ground, the student forcefully increased the collective pitch. The helicopter lifted off the ground instantly and the flight instructor advised the student pilot, "I have controls." The student subsequently "locked up on the controls" and inadvertently applied full left anti-torque pedal as he attempted to brace himself. The helicopter yawed rapidly while in the air and the tail of the helicopter struck the ground, resulting in substantial damage. The flight instructor eventually regained control of the helicopter, reduced the throttle to idle, and performed a successful autorotation.