Incident
A helicopter experienced a total loss of engine power approximately 2 miles northeast of the departure airport. The pilot executed an autorotation, landing the helicopter on a grass area adjacent to interstate 275. The helicopter sustained substantial damage, including damage to the main rotor blades and the left side of the fuselage. The pilot was uninjured.
Investigation
An examination of the helicopter revealed no anomalies that would have precluded normal operation or the installation of a carburetor temperature gauge. The pilot reported that he did not use carburetor heat during or after the takeoff from the departure airport.
Weather Conditions
At the time of the incident, weather conditions were as follows: wind from 290 degrees at 9 knots with gusts to 17 knots, visibility 10 statute miles, overcast ceiling at 2,900 feet, temperature 23 degrees Celsius, dew point 17 degrees Celsius, and altimeter 30.00 inches of mercury. According to the Carburetor Icing Probability Chart, these conditions were conducive to serious icing at glide power.