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 1 CYLINDER BROKEN AT AREA BETWEEN STEM AND HEAD OF VALVE. VALVE DROPPED INTO COMBUSTION AREA AND CAUSED PISTON DAMAGE AND EVENTUALLY ENGINE STOPPAGE. VISIBLE WEAR ON VALVE TRAIN COMPONENTS CONSISTENT WITH IMPROPER PURGING OF LIFTERS AS ADDRESSED BY SB-912-036. NO ENTRY IN ENGINE LOG BOOK TO SHOW COMPLIANCE TO SB-912-036 OR AD-113. AD WAS RELEASED 2 MONTHS BEFORE OCCURRANCE DATE.