On October 16, 1997, at 1000 central daylight time, a Bell 47G-4A helicopter, N7104J, owned and operated by Industrial Helicopters, Inc., of Lafayette, Louisiana, was substantially damaged when it impacted the ground near Welsh, Louisiana. The commercial pilot, sole occupant of the helicopter, was uninjured. A company VFR flight plan was filed and visual meteorological conditions prevailed for the Title 14 CFR Part 137 aerial application flight, which originated from Welsh Airport, Welsh, Louisiana, at 0955. In a written statement, the pilot reported that he was flying in a northeasterly direction, applying herbicide, when he noticed a power line running north to south on his right. He then observed a road in front of him running east to west. The pilot stated that he did not see the power line running east to west, adjacent to the road, breaking off from the north-south running power line. However, as he approached the road, he "sensed" that there was a power line present and executed a "hard cyclic turn to the right." The pilot was then able to view the power line, between the spray boom and the main rotor blades, "about 4 feet" from the helicopter's door. As the helicopter moved away from the power line, the pilot felt a "mild vibration," and the helicopter's tail turned into the wind, "causing a sudden rate of descent with a nose down attitude." The pilot reported that the winds were from "010 degrees at 5 knots, gusting to 7 knots." The helicopter settled, with a "slight" nose low attitude, into an area of "heavy brush." The main rotor blades struck the ground, and the helicopter rolled over onto its left side. Inspection of the helicopter, by a FAA inspector, revealed that the center frame sustained structural damage. The main rotor blades, the tail rotor blades, the tail rotor drive shaft and the gear box supports were also damaged. Attempts to contact the pilot-in-command for a telephone interview, thru the operator, were unsuccessful.