Accident Sequence
The incident occurred during a training flight when the instructor (CFI) initiated a go-around at approximately 400 feet above ground level. As part of the procedure, the CFI shut down the left engine by closing the mixture control. The student, a private pilot, then feathered the left propeller. Subsequently, the CFI moved the propeller control out of the feather position, but the propeller remained feathered. The CFI was unable to restart the left engine. The aircraft would not climb at the best single-engine rate of climb speed; it could only maintain a minimum rate of descent of 50 feet per minute. The aircraft was subsequently damaged during a wheels-up landing across furrows in an alfalfa field.
Flight Manual Guidance
The flight manual included specific warnings against feathering a propeller under certain conditions. It stated: do not feather a propeller if there is reason to suspect that the starting characteristics of the engine are not normal or that restarting in the air may be difficult or impossible; do not feather a propeller in conditions of temperature, altitude, weight, or turbulence which may prevent single-engine flight at altitudes well above the local ground elevation; do not feather a propeller at any time when conditions of terrain or other conditions may prevent the airplane from reaching an airport, in case the dead engine cannot be restarted.