As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
2 NR CYLINDER HEAD ASSEMBLY APPEARS TO HAVE FAILED DURING FLIGHT RESULTING IN A SEVERE ENGINE VIBRATION AND A FORCED LANDING. EXAMINATION OF UPPER HALF OF FAILED CYLINDER ASSEMBLY REVEALS THAT A CRACK OCCURRED AND PROPAGATED SYMMETRICALLY AROUND THE CYLINDER APPROXIMATELY .3750 BENEATH WHERE THE CYLINDER BARREL MEETS THE CYLINDER HEAD. NO INTERNAL CYLINDER /PISTON DAMAGE WAS VISUALLY OBSERVED.