On April 21, 2016, about 1112 central daylight time, a Bell 47G-2A, N64702, collided with power lines, impacted terrain, and caught fire near Los Fresnos, Texas. The pilot, the sole occupant on board, was seriously injured. The helicopter was destroyed. The helicopter was registered to and operated by Hendrickson Flying Service, Inc, Rochelle, Illinois, under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed at the time of the accident, and no flight plan had been filed. The local flight originated from Weslaco, Texas, at an undetermined time.The following account of the accident is based up a report submitted by the operator because the pilot was seriously injured and was in the hospital: The pilot was spraying a cotton field between two sets of power lines that ran parallel to his flight path. The helicopter struck a third set of power lines that ran perpendicular to the field being sprayed. The power lines were obscured by trees. A ground fire erupted after the accident, resulting in the helicopter being destroyed.