Bell 47G 5 N6288N accident near San Ardo, California

Probable cause

The failure of the pin in the outboard end of the lateral flight control torque tube.

NTSB analysis

While performing an agricultural flight, the pilot of the helicopter heard a loud noise followed by a vibration in the flight controls, and the helicopter began to roll. He noted that the cyclic was stiffer than normal, and his control inputs produced a delayed response from the helicopter. The pilot was able to return the helicopter to level flight and attempted a run-on landing; however, the helicopter began a roll to the left, which he was not able to correct before the main rotor blades impacted the ground and the helicopter rolled onto its side, resulting in substantial damage.

Postaccident examination revealed that the pin for the outboard end torque tube, which controlled lateral movement of the swashplate, was fractured.

Text from the NTSB. Open the NTSB docket for WPR16LA099 for the full record.