On March 7, 1995, at 1430 Pacific standard time, N222TE, a Hiller UH-12C helicopter, operated by Wilderness Helicopter, Inc., Billings, Montana, impacted terrain while maneuvering near Bonners Ferry, Idaho, and was substantially damaged. The student pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed and a flight plan was not filed. The local instructional flight was conducted under 14 CFR 91. In a written statement, the pilot reported that he performed an approach to a pinnacle which was approximately 25 feet higher than the surrounding terrain. The pilot maintained the hover approximately three feet above the ground for 15 to 20 seconds, then transitioned to forward flight. During the transition, the rotor rpm began to decay. The pilot stated that he did not feel that he would make his planned departure and began a right 180 degree turn and lowered the collective before flying over the edge of the river. Approximately 90 degrees into the turn, the rotor rpm decayed enough that tail rotor authority was lost. The pilot stated that he attempted to side slip the helicopter to a landing spot, however, the helicopter "stalled" just as it reached the edge of a gravel bar. The helicopter landed hard, breaking the right skid and rolling onto its right side. The pilot reported that there were no mechanical failures or malfunctions with the helicopter at the time of the accident.