On January 16, 2005, at 1340 Pacific standard time, a Robinson R22B, N1122R, experienced main rotor contact with the tailboom during a practice full-touchdown autorotation at the Rialto Municipal Airport, Rialto, California. Universal Air Academy was operating the helicopter, registered to a private company, under the provisions of 14 CFR Part 91. The certified flight instructor (CFI) and the commercial pilot-undergoing-instruction (PUI) were not injured; the helicopter sustained substantial damage. The CFI and PUI departed from the El Monte Airport, El Monte, California, about 1300 for the local area instructional flight. Visual meteorological conditions prevailed, and no flight plan had been filed. The CFI submitted National Transportation Safety Board (NTSB) Form 6120.1/2, the Pilot/Operator Report. He said that the purpose of the flight was to prepare the PUI for his CFI checkride, and they were performing full touchdown autorotations. The helicopter was aligned with the centerline of the south taxiway. Approximately 200 feet above ground level (agl), the CFI noted the following performance indications: main rotor rpm "in the green," airspeed 6 knots; and descent rate 1,300 feet per minute. At 60 feet agl, the PUI flared the helicopter and then leveled it for a full touchdown autorotation. When the helicopter was 1 foot agl, the PUI pushed the cyclic forward and the forward tips of the skids touched the ground. The helicopter then rotated aft, and the CFI assumed the controls and leveled the helicopter. Upon touchdown, the main rotor blades contacted the tailboom. The CFI noted no mechanical malfunctions with the helicopter.