What happened
While enroute to the staging area, the aircraft engine began running rough and subsequently lost power. In response to the power loss, the pilot selected a dirt road for an emergency landing.
During the landing sequence, the aircraft's left wing collided with a fence, while the right wing struck a dirt embankment. Following these impacts, the airplane veered to the right.
The investigation
An examination of the aircraft revealed two holes in the engine crankcase located above the number 2 piston position. A subsequent teardown inspection of the engine determined that the number 2 piston skirt had broken into several pieces.
Records indicated that the engine was last overhauled 1,284 hours prior to the accident, which exceeded the recommended time between overhauls of 1,200 hours. An examination of the remaining undamaged internal engine components showed normal operational action when the engine was rotated externally.