On July 4, 2000, approximately 0730 Pacific daylight time, a Bell 47G helicopter, N30DP, impacted the terrain during an aerial application run near Haines, Oregon. The commercial pilot, who was the sole occupant of the aircraft, received minor injuries, and the helicopter, which was owned and operated by the pilot, sustained substantial damage. The 14 CFR Part 137 aerial application flight, which had been airborne for about 10 minutes, was being operated in visual meteorological conditions. No flight plan had been filed, and there was no report of an ELT activation. According to the pilot, who had to approach his spray runs over rolling terrain, he had completed one run and was maneuvering for the second when the aircraft contacted the ground. He said that as he descended over a small hill while lining up for the second swath, he misjudged his rate of descent toward the terrain, and waited too long to initiate his level off. This resulted in the skids of the helicopter contacting the surface of the field. Immediately after the aircraft's skids touched the terrain, it rolled over at least three times. The pilot further stated that there did not appear to be any problems with the engine or the aircraft's flight control system.