ERA23LA005

According to the pilot, he purchased the multiengine airplane about 3 months prior to the accident, then flew it uneventfully to another airport for an annual inspection and to have other maintenance issues addressed. After the annual inspection was completed, several engine-runs and taxi checks were performed with no anomalies noted. On the day of the accident, the pilot completed a preflight inspection and intended to fly to his home airport. The mechanic that completed the annual inspection told him that he had drained black sooty water from the fuel tanks. The pilot went out to the airplane and drained water out of the tanks until the fuel was clean and clear. About 5 to 6 minutes into the flight, the left engine began to run rough and lost partial power. When the pilot increased the power on the right engine, the right engine immediately lost all power. He set up for an off-airport landing and noticed a highway, so he lined up with the centerline of the highway and landed. During the landing rollout, the right-wing tip collided with a highway sign. The airplane subsequently rolled off the highway and came to rest upright in a field. Postaccident examination of the airplane revealed substantial damage to the right-wing spar. Two days after the accident, more water was sumped from both fuel tanks. After the water was removed, both engines ran normally. The pilot added that there were no preimpact mechanical malfunctions with the airplane. Based on this information, it is most likely that the loss of engine power the pilot experienced during the accident flight was due to fuel contamination.