Accident Details
A certified flight instructor reported that he and his student were flying a helicopter in the traffic pattern on the downwind leg. The student pilot was flying the aircraft when the instructor directed him to reduce power to begin the descent for the base turn to final approach. The student complied by reducing manifold pressure by approximately one inch of manifold pressure.
The instructor then took control of the helicopter and further reduced manifold pressure by six to seven inches. At that point, the student attempted to apply carburetor heat but mistakenly moved the mixture control, which is located next to the carburetor heat control, to the idle cutoff position. This inadvertent action caused an immediate loss of engine power.
Emergency Response
Recognizing the loss of power, the instructor turned the helicopter 180 degrees into the wind and initiated an autorotation. The instructor stated that the descent began from an altitude of approximately 300 feet above ground level. His chosen landing site was a school yard with children present. To avoid endangering the children, he maneuvered the helicopter to an alternative landing site.
Landing and Damage
During the landing, the helicopter impacted the ground hard. The force of the landing caused the skids to spread outward. Additionally, the main rotor blade struck the tail boom, severing it from the helicopter. The aircraft sustained substantial damage.
Additional Information
The investigation source did not specify the type or registration of the helicopter, the date of the incident, or whether any injuries occurred. The statements from the flight instructor form the basis of this account.