As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) IN CRUISE FLIGHT, THE NR 1 ENGINE LOST POWER AND BEGAN TO BACKFIRE. ENGINE SHUT DOWN AND FEATHERED. UPON INSPECTION OF ENGINE NR 9 CYLINDER EXHAUST ROCKER BOLT FOUND SHEARED AT NUT AND BOLT HAD DISENGAGED FROM CYLINDER EAR ASSEMBLY. NEW BOLT AND NUT ASSEMBLY INSTALLED, VALVE CLEARENCES ADJUSTED, MAIN OIL SCREEN AND NO CONTAMINATION FOUND. ENGINE GROUND RUN SERVICEABLE AND RETURNED TO SERVICE.