Overview
A helicopter engaged in a coyote eradication mission crashed approximately two miles from its launch point. According to ground crew, there were no witnesses to the accident. Radio contact was lost five minutes after initial communication.
Wreckage Examination
Examination of the wreckage indicated a high rate of descent terrain collision with low or no engine and rotor speed. On-site and subsequent inspection of the rotorcraft's engine, engine components, transmission, clutch, main and tail rotor drive trains, and flight controls revealed no mechanical malfunction or failure.
Anomaly Discovery
A spent shotgun shell was found lying loose under the seat panel. The shell had a crush mark that appeared to fit between two crushing surfaces: the throttle bell crank and the correlator assembly for the right seat, where the right collective control column had been removed.
Simulation Results
Simulations were conducted numerous and separate times using an undamaged HU-269C and identical spent shotgun shells, by both the USDA accident investigator and the NTSB investigator. It was determined that the jam only interfered with throttle action toward the decrease power setting and was easily overpowered by a stronger twisting action.