On July 29, 2014, at 1651 eastern daylight time, a Hughes 369D helicopter, N89ZC, collided with the terrain following a loss of engine power while trimming trees in West Liberty, Ohio. The commercial pilot was seriously injured. The helicopter sustained substantial damage. The helicopter was registered to DAH Aircraft LLC and operated by Rotor Blade LLC as a 14 Code of Federal Regulations Part 133 external load flight. Visual meteorological conditions prevailed for the flight, which did not operate on a flight plan. The local flight originated from a nearby field at 1501. The pilot was using a 10-bladed aerial saw to trim trees along a railroad track when the accident occurred. A witness reported the engine sounded like it lost power and the tail of the helicopter oscillated to the left as the helicopter began losing altitude. The helicopter then rolled to the left and descended to impact with the trees and terrain. A postaccident examination of the helicopter was conducted by a Federal Aviation Administration inspector. The inspector reported the tail boom separated from the helicopter during the impact. The tail rotor drive shaft did not show evidence of torsional twisting. The main and tail rotor blades contained little damage. He reported there was no evidence of fuel spill at the accident site. The helicopter's fuel system was intact and there was no fuel present in the fuel tank or in the fuel line at the engine. The inspector applied electrical power to the helicopter and the fuel quantity indicator showed the tank was empty. The helicopter was topped off with fuel prior to the flight. According to the helicopter operator, the helicopter holds 62.4 gallons of fuel. The pilot reported the helicopter consumes about 30 gallons per hour. The operator stated the spot tracker information showed the helicopter flew 1 hour and 50 minutes from the last fueling to the time of the accident and they drained about one quart of fuel from the helicopter after the accident. The operator stated the pilots and ground crew time the flights for fuel consumption. The ground crew gave the pilot a one hour time check followed by additional 15 minute time checks prior to the accident.