What happened
The flight encountered a critical mechanical failure while cruising at 6,000 feet when the engine suddenly seized. Faced with unsuitable surrounding terrain for a conventional emergency landing, the pilot made the decision to attempt a forced landing on a nearby highway.
To ensure clearance over power lines that crossed the roadway, the pilot kept the landing gear retracted until reaching approximately 50 feet above ground level. The aircraft subsequently touched down on the pavement with the landing gear in a partially extended position.
The investigation
A detailed teardown of the engine was conducted to determine the root cause of the seizure. Examination revealed that the exhaust valve for cylinder number five had failed specifically in the area between the stem and the head.
This mechanical failure led directly to the destruction of the connecting rod and the cylinder itself, resulting in the complete loss of power during flight.