On July 13, 2001, at 0820 hours Pacific daylight time, a Hiller UH-12E, N9281P, landed in soft soil and rolled onto its right side at Blythe, California. The commercial certificated pilot, the sole occupant, was not injured; however, the helicopter was substantially damaged. The aerial application flight was operated under 14 CFR Part 137 by H&H Aerial Applicators. Visual meteorological conditions prevailed and no flight plan was filed. The helicopter departed from a local helipad near the work site at 0815. The pilot told the Safety Board investigator that, following an application pass, he sensed a decrease in engine power and elected to make a precautionary landing. During the landing in a cotton field on irregular, wet ground, the right skid settled into the soil and the helicopter rolled onto its right side. In his report to the Safety Board, in the section entitled "Mechanical Malfunction Failure" the pilot checked "no."