Incident Description
The aircraft was conducting the final sowing sortie of the mission, after which the pilot planned to return to home base. During the takeoff roll, the pilot reported that the engine appeared to overspeed and that the aircraft did not become airborne. After departing the airstrip, the aircraft sank into a shallow gully located beyond the end of the strip.
Post-Accident Examination
Following the accident, inspectors found that one propeller blade was free to rotate about its feathering axis. Metallurgical analysis indicated that the pitch change knob on that blade had failed as a result of ductile overload. A second pitch change knob was bent and cracked but had not separated from the blade. The overload sustained by the pitch change knobs was determined to have occurred at impact, not in flight.
Investigation Outcome
Investigators established no reason for the aircraft's failure to become airborne. The cause of the accident remains undetermined.