What happened
During a Part 135 operation, the pilot taxied the aircraft into position for departure. Before beginning the takeoff roll, the pilot checked the tail wheel locking lever to ensure it was engaged. The takeoff run commenced in conditions characterized by gusting winds.
The wind gusts exceeded the established crosswind limits for the specific aircraft type being operated. As the airplane accelerated down the runway, the tail wheel failed to remain locked. This mechanical failure resulted in a loss of directional control. The pilot was unable to maintain the runway centerline, and the airplane ground looped.
The uncontrolled turn caused the airplane to depart the side of the runway. It subsequently entered a ditch located adjacent to the airfield. There is no information provided regarding injuries or damage extent in this specific narrative segment.
The investigation
The factual narrative indicates that the tail wheel was not locked at the time of the takeoff attempt. This condition directly contributed to the loss of directional control during the high-speed ground roll.