N268SHRobinson Helicopter R22 BETA · 2007

The certified flight instructor said he and his student were flying the helicopter in the traffic pattern on the downwind leg. The student pilot was flying and he was told by the instructor to reduce the power to begin the descent for the base turn to final. The student reduced the power by approximately 1 inch of manifold pressure. The instructor then took control of the helicopter and reduced the power by an additional 6 or 7 inches of manifold pressure. He said that the student pulled the mixture control out to the idle cutoff position, which resulted in a loss of engine power. The student had intended to apply carburetor heat and instead inadvertently moved the mixture control, which was located next to the carburetor heat. The instructor turned the helicopter 180 degrees into the wind and simultaneously entered an autorotation from 300 feet above the ground. His selected landing site turned out to be a school yard with children present. He maneuvered the helicopter to a new landing site, but subsequently landed hard. The landing skids were spread and the main rotor cut off the tail boom.

In a written statement, the certificated flight instructor (CFI) reported that the purpose of the flight was to provide the student pilot training. The student pilot made several approaches and a practice hover autorotation before repositioning the helicopter to a different area of the airport. They planned to perform more hover autorotations and the CFI continued to guard the flight controls. The CFI deviated from the normal procedure they had practiced of communicating and counting down before rolling the throttle to the closed position. The CFI initiated the hover auto without communication. In response to the movement the student depressed the left [improper] anti-torque pedal and the helicopter began to spin. The CFI could not regain control and the helicopter rolled.

The CFI further stated that the accident could have been prevented if he had briefed the student more thoroughly on the maneuver and if he had assumed authority of the controls earlier in the maneuver. The CFI reported no pre impact mechanical malfunctions or failures with the helicopter