As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) EXHAUST VALVE IN NR 2 CYLINDER BROKEN AT AREA BETWEEN STEM AND HEAD OF VALVE. VALVE DROPPED INTO COMBUSTION AREA AND CAUSED PISTON DAMAGE AND EVENTUALLY ENGINE STOPPAGE. VALVE TRAIN COMPONENTS WEAR CONSISTENT WITH IMPROPER PURGING OF LIFTERS AS ADDRESSED BY SB-912-036. DAMAGE TO NR 3 CYLINDER EXHAUST VALVE AND VALVE SEAT INDICATE THIS CYLINDER WAS SUFFERING THE SAME MANNER.