For about 30 minutes, the flight instructor and his student pilot were practicing hovering and landings on a level concrete area. During the accident touchdown, a wind gust or wind shift occurred and the helicopter shifted sideways. The pilots felt the skids "catch" and the left side of the helicopter began to lift. The flight instructor called for and took control of the helicopter. The student pilot had not released his controls. The helicopter then rolled onto its right side. The helicopter sustained substantial tailboom damage. The pilot's accident report indicated that there were no helicopter mechanical malfunctions.