Event Description
A pilot reported that while cruising at 500 feet above ground level, the engine began to run roughly. The pilot decided to land the airplane to investigate the problem. During the landing roll, the right wing tip struck a road sign that was obscured by brush. According to the pilot, the impact spun the airplane around to the right. Subsequently, the nose gear struck a sand embankment on the edge of the road, causing the airplane to nose over.
Wreckage Examination
Examination of the wreckage revealed that the left magneto rear cover had separated from the magneto's main case, exposing the gears and points. Three of the four screws that held the magneto cover in place were missing, and the fourth screw had sheared off in the case. Both magnetos were tested for spark, and no abnormalities were found. Additionally, examination of the fuel in the tanks showed evidence of water and sediment.