On January 15, 2001, about 1210 Pacific standard time, a low skid-equipped Bell 206B helicopter, N58WW, sustained substantial damage subsequent to a hard landing following a practice autorotation at McMinnville Municipal Airport, McMinnville, Oregon. The helicopter is owned by CRT Leasing of Tualatin, Oregon, and was being operated as a visual flight rules (VFR) instructional flight under Title 14 CFR Part 91, when the accident occurred. The certified flight instructor, and private pilot (airplane) receiving helicopter training, were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local instructional flight. The flight originated from Aurora, Oregon, approximately one hour prior to the accident. There was no fire and no report of ELT activation. During a telephone interview on February 2, 2001, and a subsequent written statement, the instructor pilot reported that she and the student pilot were practicing power recovery autorotations at the McMinnville airport. During the fifth practice autorotation, while descending through an altitude of approximately 200 feet AGL, the instructor pilot increased throttle and collective in an effort to slow the helicopter's decent rate and recover from the autorotation. Shortly thereafter, the pilot noted that the main rotor RPM was not increasing and that she had inadvertently applied only partial power for the recovery. The instructor pilot lowered collective, increased power and performed a straight-in run-on landing. The helicopter touched down 3-4 feet beyond the numbers on runway 35. During the run-on landing, the helicopter encountered a rough/uneven spot on the runway surface and came to an abrupt stop. Post accident inspection revealed that the helicopter fuselage sustained substantial damage to both aft cross tube attach points and rear bulkhead.