Accident Overview
On September 16, 2017, at about 1715 eastern daylight time, an amateur-built Exec 162-F helicopter, registration N123XZ, conducted a forced landing to a field near Plymouth, Indiana. The helicopter was registered to North Indiana Rotor LLC and operated by a private individual under 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and the flight operated without a flight plan. The local flight had departed from Plymouth Municipal Airport (C65), Plymouth, Indiana.
Sequence of Events
According to the pilot, while approaching the airport, the helicopter's engine rpm increased and the rotor rpm decayed. Unable to maintain altitude, the pilot performed an autorotation to a field. The helicopter landed hard, resulting in bent skids and a buckled tail boom, which constituted substantial damage. The pilot and passenger were not injured.
Examination Findings
An examination of the helicopter by a Federal Aviation Administration inspector revealed that the helicopter was equipped with a Pro Drive system for driving the main rotor blades. The main rotor drive belt, a Goodyear Falcon PD belt, had been installed approximately 3.5 flight hours prior to the accident. The belt had begun losing teeth, leading to a failure to drive the main rotor blades. This belt failure resulted in the loss of rotor rpm and the subsequent forced landing.