Engine Failure
The engine began to run rough and smoke filled the cockpit.
Approach and Landing
During the downwind approach to a field, forward visibility was limited by the smoke. On short final, the pilot observed a fence across the landing area and pulled the yoke all the way back. The airplane made a hard landing and traveled through the fence.
Post-Accident Damage
Following the landing, the nose gear collapsed. The engine, fuselage, and wings were damaged. Engine oil was found on the engine cowling and in the area of the #4 cylinder. The oil sump contained approximately 1.5 quarts of oil. The exhaust valve push rod and the push rod tube on the #4 cylinder were bent and were no longer in place. The engine time since the last major overhaul was 697.65 hours, and the time since the last annual inspection was 26 hours.