Accident Overview
A helicopter experienced a hard landing during a practice autorotation, resulting in structural damage to the tail boom and fuselage. The incident occurred when the instructor pilot simulated a loss of engine power during cruise flight. The student pilot, who was training to become a flight instructor, initiated an autorotation to a field.
Event Details
Following the practice autorotation, the instructor pilot attempted to apply engine power. However, the engine "immediately quit" according to the instructor. Despite applying full collective to cushion the landing, the helicopter touched down hard in the field, causing structural damage to the tail boom and fuselage.
Post-Accident Examination
After the accident, the operator returned the helicopter to their facility and conducted a test run of the engine. No anomalies were detected during the test. The operator believed that the conditions were suitable for the development of carburetor ice during the autorotation.
Weather Conditions
Review of archived weather data for the day of the accident revealed that the closest weather observation facility reported a temperature of 6 degrees Celsius and a dew point of 5 degrees Celsius. Plotting these temperatures on a carburetor icing probability chart indicated that conditions likely existed for serious icing at any power setting.