On September 29, 2007, at 1000 mountain daylight time, a Robinson R-22 BETA, N74557, piloted by a solo student pilot, descended uncontrollably, struck trees, and impacted terrain 40 miles northwest of Silver City, New Mexico. The local personal flight was being conducted without a flight plan under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed at the time of the accident. The student pilot was not injured and the helicopter was substantially damaged. The flight originated from a private ranch at Douglas, Arizona, at 0630. The student pilot reported that he was tying to locate a fence in the bottom of a narrow canyon . As he was making a turn, the helicopter encountered a tailwind which caused it to settle. The main rotor struck a tree and the helicopter subsequently impacted the terrain. The helicopter was found resting on it's left side. An examination of the helicopter showed substantial damage to the cabin area and the main rotor separated. An examination of the helicopter systems showed no anomalies.