Piper PA-14 N5126H accident near King Salmon, Alaska

Probable cause

The pilot's failure to use continuous carburetor heat while operating in carburetor icing conditions, resulting in carburetor ice and subsequent partial loss of engine power.

NTSB analysis

The pilot reported that the weather at his destination airport had deteriorated to a 500-700 foot ceiling with 10 miles of visibility. He was instructed by air traffic control personnel to hold outside the airport's controlled airspace, and to expect a special visual flight rules clearance in 30 minutes. Throughout the hold, the pilot cycled the carburetor heat intermittently on and off. After about 25 minutes holding, he decided to reposition to a location between his destination and alternate airport. As he started to fly towards this new position, the engine began losing rpm and running rough. He applied carburetor heat and full mixture, but the engine continued to run rough. He made a forced landing along the edge of a stream, during which the right wing and fuselage received substantial damage. About the time of the accident, the destination airport reported both the temperature and dew point as 07 degrees Celsius. According to the Federal Aviation Administration Carburetor Icing Probability Chart, an aircraft encountering those ambient conditions could expect serious carburetor icing while at cruise power. Examination of the airplane and engine revealed no mechanical failures or malfunctions that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for ANC10LA061 for the full record.