What happened
On April 30, 2019, an Aerospatiale AS350, registration N350DL, was involved in an incident near Sula, Montana, following an aerial application flight. While the pilot was positioned in a predetermined operations zone near a semi-truck loading hopper, a second truck arrived to refill the hopper. This process released fertilizer dust, causing the pilot to become concerned about deteriorating visibility.
To avoid the dust, the pilot informed the ground crew of his intent to move to a temporary operations zone. After repositioning the bucket, the pilot began easing the helicopter backward to maintain a clear view of approaching ground equipment, specifically a skid steer. During this maneuver, the pilot heard a loud noise and disconnected from the long-line. The pilot then landed the aircraft without further incident. There were no injuries resulting from this event.
The investigation
Post-accident examination of the aircraft determined that the tail rotor blade had sustained substantial damage. Investigators found that the auger from the semi-truck loading hopper was fully extended behind the helicopter at the time of the event. The pilot indicated that the helicopter may have been backed into the extended auger.