On August 25, 2003, about 1200 Pacific daylight time, a Hughes 269C, N58363, collided with terrain during a practice autorotation landing in an open field 6 miles southwest of Columbia Airport, Columbia, California. The helicopter was operated by the certified flight instructor (CFI)/owner under the provisions of 14 CFR Part 91. The CFI and student pilot were not injured, and the helicopter sustained substantial damage. Visual meteorological conditions prevailed, and a flight plan had not been filed. The flight originated at Columbia Airport about 1130. The CFI stated in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that the student was preparing for his commercial helicopter add-on rating. They were practicing autorotations to an open field. During the fourth autorotation landing attempt, the student held the landing flare too long and too low to the ground. The CFI felt the tail rotor strike the ground. He then came onto the controls and landed the helicopter after it had yawed 180 degrees.