Gordon Brumm

Rockwell Grand Commander 680

About 5-10 min after takeoff the pilot leaned the mixture on a rough running engine. About 30 minutes later the left engine began to overspeed. The pilot was unable to feather the prop. The pilot returned toward the departure point with max power on the right engine. Unable to reach the airport, an emergency landing was made on a highway, directional control was lost, and the airplane collided with trees. Last annual was in 1978. Left propeller start lock pin blade L3 corroded, in extended position. Left propeller pitch control cable separated, frayed, corroded. General deterioration of piston rings and #6 conrod. Right prop governor control cables corroded, frayed. Right engine #5 intake pipe connection and hose missing. All compression rings pistons #1 and #5 severely worn, top two compression rings piston #2 seized. No record that the airplane had been inspected by an a&p mechanic or FAA approved airframe repair station. Pilot stated flight manual not available or used during ground or flight operations.