What happened
On March 18, 2024, at approximately 1720 EDT, a Hughes 369D helicopter, registration N102SU, was performing external-load tree-trimming operations near Belleville, West Virginia. The pilot had completed several successful flights earlier that day without incident. During the flight in question, the pilot was evaluating a tree line above a creek for safe trimming when a loud noise occurred, followed by a rapid descent of the aircraft.
To mitigate the impact, the pilot maneuvered the helicopter toward smaller trees. During the descent, the pilot briefly lowered the collective to maintain rotor RPM and raised it just before hitting the ground. The pilot also chose to keep the external cutting saw attached to the aircraft, hoping it would absorb some of the impact forces. The helicopter struck trees and branches before impacting the ground and coming to rest in an inverted position in hilly terrain. The pilot sustained one serious injury and was not killed.
The investigation
Investigators examined the wreckage and found the tail boom separated from the fuselage, with the main rotor blades and various rotor head components scattered across the area. The nose section showed crushing damage consistent with tree strikes. The external saw assembly remained attached, though its support pipe was fractured.
An examination of the drivetrain, including the Kaflex driveshaft, clutch subassembly, and transmission input coupling, showed no evidence of mechanical failure or abnormal wear. All splined connections were well-lubricated, and the clutch and bearings were functioning properly. The engine examination showed no evidence of pre-impact fire or malfunction; however, the compressor inlet and rotor assembly sustained severe damage. Blades from stages 1 through 5 were fractured near the hubs, a condition consistent with hard-body ingestion. While the specific source of the material could not be identified, the engine showed no signs of fatigue failure or manufacturing defects.