Incident Overview
Following police patrol activities, the aircrew landed and refueled the helicopter. They then took off to practice autorotative landings. Two such landings were performed on Runway 22, followed by two additional landings on an adjacent grass area.
Sequence of Events
After the second landing on the grass, the pilot began to take off again. He stated the helicopter was traveling level along the ground with very little weight on the skids at a speed of 5 to 10 mph. He then observed a drainage ditch, surrounded by high grass, approximately 10 feet ahead. The pilot applied power and increased the collective to clear the ditch. According to reports, the sounds of the engine increased; however, the helicopter started to roll and yaw to the right. Power was reportedly reduced to correct the yaw, but the helicopter's right skid contacted the turf. Subsequently, the aircraft rolled further to the right, and the main rotors contacted the ground.
Examination and Findings
An examination of the engine and airframe was conducted. No pre-crash mechanical failure or malfunction was found.