NTSB Identification: ANC11LA099
14 CFR Part 91: General Aviation
Accident occurred Tuesday, August 30, 2011 in Unalaska, AK
Probable Cause Approval Date: 05/15/2012
Aircraft: ROBINSON HELICOPTER R22 BETA, registration: N169CW
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The pilot reported that, during cruise flight, the engine ran rough for about three engine revolutions before losing total power. The pilot entered an emergency autorotation and landed the helicopter in a shallow bay. Postaccident examination of the helicopter did not reveal any mechanical anomalies that would have precluded normal operation; however, a detailed engine examination was not completed. According to a carburetor icing probability chart, conditions at the time of the accident were conducive to severe carburetor icing at both cruise and glide power settings. Although carburetor icing was a possible initiating event for the loss of engine power, carburetor icing could not be determined.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

A loss of engine power in cruise flight for undetermined reasons.

Full narrative available

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