HISTORY OF FLIGHTOn November 16, 2018, about 1130 central standard time, a Bell OH-58C helicopter, N510CP, was substantially damaged when it was involved in an accident near Verbena, Alabama. The pilot and passenger were fatally injured. The airplane was operating as a Title 14 Code of Federal Regulations Part 91 positioning flight. According to the mechanic, the helicopter was being repositioned to the Chilton County Airport (02A), Clanton, Alabama, for routine maintenance. On the day of the accident, the pilot departed Columbus Airport, Columbus, Georgia (CSG), then stopped at Auburn University Regional Airport (AUO) to pick up a passenger before continuing to 02A. According to witness statements, the helicopter approached a river from the east and then flew north over the river at a low altitude before doing a maneuver to head south. One witness saw the helicopter "catch and turn" then impact the water. Another witness reported hearing a loud explosion, and when he went to the river, the wreckage was below where the power lines were, but the power lines were no longer across the river. After the accident, a severed power line was located in the river. WRECKAGE AND IMPACT INFORMATIONAt the accident site, the Coosa River was about 1,500 ft wide; the wreckage was located midway across the river, about 700 ft from shore and about 400 ft downstream from power lines. The helicopter main rotor hub and blades were not recovered. The main rotor mast exhibited an overstress fracture where the main rotor hub had separated from the mast; deformation of the mast was visible near this fracture. The upper wire strike protection was examined and was intact. The main transmission input shaft was not recovered. The freewheeling unit could be rotated in the freewheeling direction. The first segment of the tail rotor drive shaft, between the engine reduction gearbox and the oil cooler blower, was fractured but remained connected at its ends. Tail rotor control continuity was confirmed from the tail rotor blades to the forward section of the tail boom. Manipulation of the tail rotor drive shaft at the forward section of the tail boom resulted in movement of the tail rotor. In addition, continuity was confirmed from the forward section of the tail boom to the tail rotor pitch links. Tail rotor control continuity from the bellcrank forward of the main rotor transmission to aft fuselage, where the tail boom separation occurred, was confirmed through multiple overload fractures. The tail rotor blades were whole and did not exhibit impact damage. The main rotor transmission was separated from its right-side pylon mount but remained connected to its left-side pylon mount. Both the left and right transmission pylon mounts remained installed on the airframe. The main rotor hydraulic actuators remained installed on the airframe and its attachments were secure. The main transmission input shaft coupling exhibited an overload fracture. Main rotor flight control continuity was confirmed from the main rotor swash plate and collective lever to main rotor hydraulic actuators, and subsequently to the broom closet through multiple overload fractures. Both cyclic controls were impact separated from their respective mounts but remained attached to the cockpit structure via electrical wiring through the mounts. The left collective control remained attached to the fuselage through wires. No pedal controls or the right collective control were located. Fuel was present in the fuel supply line to the fuel spray nozzle and no debris was noted in the fuel. The engine controls were impact separated from the engine control attachment points. The engine control on the left collective control appeared to be intact and continuous through the cable until the steel sheath was pulled, but not separated. The engine oil reservoir contained engine oil. The engine bleed valve could be operated by hand. The N1 and N2 turbines could not be rotated. The compressor vanes were impact damaged. A few of the 1st stage compressor blades were bent opposite the direction of travel. In addition, rotational scoring was noted on the compressor blade case. The oil cooler blower could be rotated by hand. The 1st stage power turbine blades that were examined with a borescope showed no thermal damaged. Examination of the engine did not reveal evidence of any preimpact damage, failure, or fire. MEDICAL AND PATHOLOGICAL INFORMATIONThe autopsy of the pilot was performed by the Alabama Department of Forensic Sciences, Montgomery, Alabama. The cause of death was blunt impact injuries. Toxicology testing performed at the Federal Aviation Administration Forensic Sciences Laboratory tested negative for carbon monoxide and ethanol. Rosuvastatin was identified in blood and urine specimens, which is a prescription cholesterol-lowering medication that is not considered impairing.