Stinson V77 N715FB accident near Jordan, Minnesota

Probable cause

A partial loss of engine power due to carburetor icing.

NTSB analysis

The pilot was conducting a personal flight to break in the recently overhauled engine. After about 30 minutes, when the airplane was about 2,000 ft above ground level, the engine started to backfire and lose power. The pilot attempted to troubleshoot the problem by switching fuel tanks; adjusting the engine throttle, mixture, and propeller controls; and selecting the individual magneto positions, to no avail. He performed an emergency landing to a soft field; the airplane subsequently nosed over during the landing roll, and the rudder sustained substantial damage. Postaccident examinations of the airframe, engine, and magnetos found no mechanical malfunctions or failures that would have precluded normal operation. Weather conditions at the time of the accident were conducive to serious carburetor icing at cruise power. Thus, it is likely that the engine lost power due to serious carburetor icing.

Text from the NTSB. Open the NTSB docket for CEN16LA369 for the full record.