"***This report was modified on June 3, 2019. Please see the docket for this accident to view the original report.*** On August 10, 2017, about 1400 mountain daylight time, a Hughes 369D helicopter, N58424, had its tail rotor impact a powerline near Villa Grove, Colorado. The pilot received serious injuries. The helicopter sustained substantial tailboom and fuselage damage. The helicopter was registered to Quicksilver Air Inc. and operated by Patrol Helicopters Inc. as a 14 Code of Federal Regulations Part 133 rotorcraft external load flight. Day visual meteorological conditions prevailed in the area about the time of the accident, and the flight was not operated on a flight plan. The local flight originated from a field near the accident site. According to the pilot's accident report, the purpose of the flight was to assist power line construction. After pulling a sock line through several structures, the helicopter was flown inside an angle tower. As the pilot was flying the helicopter away from the angle tower, he flew the helicopter to his right while planning on backing up at the same time. The helicopter's speed to the right was faster than planned. He stated that the helicopter's main rotors contacted a tower before it came into view, and the helicopter subsequently "crashed." The pilot indicated that the helicopter did not have any mechanical malfunctions. The pilot was not wearing a helmet.