Primary finding
Probable cause
The pilot's improper preflight planning which resulted in a jammed cyclic control while maneuvering.
Investigator assessment
Analysis narrative
The pilot reported that the helicopter was in a three-foot hover, moving forward, when control was lost and the helicopter collided with terrain. The pilot reported the left cyclic control was removed prior to the flight; however, the protective cover was not installed. He stated that during the accident flight, test equipment (used for track and balance) "became entangled" at the left cyclic attach point and prevented full cyclic control.
Source record
Factual narrative
The commercial pilot and mechanic were conducting a maintenance test flight to facilitate a dynamic track and balance of the main rotor system when the accident occurred. In a written statement, the pilot reported the helicopter was in a three-foot hover, moving forward, when control was lost. The helicopter subsequently collided with terrain resulting in substantial damage to the fuselage. The pilot reported the left cyclic control was removed prior to the flight; however, the protective cover was not installed. He stated that during the accident flight, the test equipment (used for track and balance) "became entangled" at the left cyclic attach point and prevented full cyclic control.