As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS IN-FLIGHT WHEN NR 1 CYLINDER BARREL SEPARATED FROM HEAD CAUSING A FORCED LANDING. NO FURTHER DAMAGE OCCURRED TO AIRCRAFT AND NO INJURIES OCCURRED DURING THIS INCIDENT. SUSPECT CAUSE WAS ATTRIBUTED TO AGE AND TIME ON CYLINDER.