On August 5, 2015, about 1705 central daylight time, a Hughes 269B helicopter, N9427F, collided with a power line during cruise flight near Atkinson, Illinois. The pilot sustained serious injuries, and the helicopter was destroyed during a postimpact fire. The helicopter was registered to the commercial pilot and operated under Title 14 Code of Federal Regulations Part 91 without a flight plan. Day visual meteorological conditions prevailed for the personal flight. The local flight was believed to have originated from the pilot's residence located near Genesco, Illinois, at an unknown time.A witness to the accident reported that he was working on his property when he heard the helicopter approach his position. He then heard a loud "pop" and saw a broken power line overfly his position. The witness turned around and saw the helicopter wreckage in a nearby field engulfed in fire. He immediately responded to the accident site and removed the pilot from the burning wreckage. Another witness reported that initially a loud noise drew her attention towards the helicopter's position. She saw the helicopter briefly in flight before it impacted the ground in a level attitude. She reported that there was an extensive ground fire after the accident. Another witness reported seeing the helicopter flying about 20 ft above soybean fields before it flew out of her line of sight. The witness subsequently heard the sound of emergency vehicles responding to the accident site. The pilot was hospitalized for several months after the accident with serious burns sustained during the postaccident fire. The pilot does not recall the accident flight. A postaccident examination of the helicopter was completed by Federal Aviation Administration inspectors. An onsite survey revealed that the helicopter had collided with a north/south power line located about 184 ft northeast of the main wreckage. The height of the power line was about 40 ft above the ground. A wreckage debris path extended about 98 ft southwest into a soybean field. The helicopter was destroyed during the postimpact fire. The only identifiable components remaining were the engine, main transmission, and some cockpit instruments. An examination of the engine confirmed internal engine and valve train continuity as the engine crankshaft was rotated. Compression and suction were noted on all cylinders in conjunction with crankshaft rotation. Both magnetos and their respective ignition harness were damaged during the postimpact fire and could not be tested. The sparkplugs electrodes exhibited heavy combustion deposits. The oil strainer contained oil and was clear of debris. The mechanical fuel pump functioned as designed when the pump lever was moved by hand. All fuel lines remained connected to the flow divider manifold. The postaccident examination did not reveal any anomalies that would have precluded normal operation. A postaccident review of available meteorological data established that day visual meteorological conditions prevailed at the accident site. The nearest aviation weather reporting station was located at Quad City International Airport (MLI) about 24 nautical miles west of the accident site. At 1652, about 13 minutes before the accident, the MLI automated surface observing system reported: wind 50° at 8 knots, 10 miles surface visibility, clear sky, temperature 28°C, dew point 17°C, and an altimeter setting 29.97 inches of mercury. According to data obtained from the U.S. Naval Observatory, at the time of the accident, the sun was approximately 34° above the horizon to the west-southwest (263°). Sunset was at 2013 on the day of the accident.