Event Summary
A dual instructional flight experienced an engine power loss while the aircraft was at an altitude of 600 feet above ground level (AGL) on the downwind leg for landing on runway 30. The flight instructor, who was providing training, decided to land downwind on runway 12, a 2,700-foot grass strip.
Landing and Overrun
The aircraft touched down on the wet grass runway beyond the midfield point. Due to the moisture on the grass, braking effectiveness was minimal. The aircraft was unable to stop within the remaining runway length, resulting in an overrun beyond the runway end. It subsequently traversed two fences and nosed over, coming to rest in an inverted position.
Engine Examination
A post-incident examination of the engine revealed that an exhaust valve had failed. The inspection focused on the powerplant and identified the valve failure as a finding.