Background
The accident occurred during an aerial application flight while the helicopter was maneuvering at low level over a field. The pilot reported that sunlight was directly in his eyes, prompting him to adjust the sun visor.
Sequence of Events
To adjust the visor, the pilot removed his hand from the collective control. He stated that he used his leg to block the collective from moving while he made the adjustment. Shortly after, the helicopter encountered mild turbulence. The turbulence caused the pilot's leg to be bumped away from the collective. With the leg no longer blocking it, the collective slipped down. This led to the helicopter impacting the ground. The helicopter then rolled over onto its side.
Damage and Mechanical Status
The helicopter suffered substantial damage to its tailboom and cockpit. The pilot reported that there were no mechanical failures or malfunctions with the helicopter's flight control system or engine prior to the accident.