Robinson R22 Beta N179SH accident near North Palm Bch, Florida

Probable cause

A loss of engine power due to carburetor icing. Contributing to the accident was unsuitable terrain for a forced landing.

NTSB analysis

The helicopter was transitioning along a beach at 500 feet and 80 knots. The certificated student pilot had just contacted an air traffic control tower when the engine appeared to lose power. The student pilot raised the collective, but the situation "worsened," and he noticed a slight yaw. The student pilot then lowered the collective, and turned the helicopter left, into the wind. He subsequently completed an autorotation into the surf. The student pilot noted that prior to the loss of engine power, he didn't notice any unusual vibrations or noises, but did notice a "significant loss of power which resulted in an immediate loss of altitude." He also noted that it felt like "the sinking and yawing one experiences when settling with power." A postflight examination of the helicopter revealed no mechanical anomalies that would have precluded normal operation. Utilizing the ambient temperature and dew point, a carburetor icing probability chart produced by the National Research Council of Canada indicated a probability of "serious icing at glide power," while another chart in the FAA's Tips on Winter Flying pamphlet indicated that carburetor icing conditions bordered between "serious icing - glide power" and "light icing - glide or cruise power."

Text from the NTSB. Open the NTSB docket for NYC08LA078 for the full record.