What was found
(CAN) DURING CRUISE, NR 1 ENGINE BMEP INDICATION WAS FLUCTUATING, AIRCRAFT HAD A SLIGHT YAW. THE RETARDANT LOAD WAS JETTISONED AND THE ENGINE WAS SHUT DOWN AND PROP FEATHERED. THE AIRCRAFT RETURNED TO BASE. UPON INVESTIGATION NR 15 CYLINDER EAR WAS FOUND CRACKED. THE CYLINDER WAS REPLACED, ENGINE WAS GROUND RUN AND LEAK CHECKED AND THE AIRCRAFT WAS RETURNED TO SERVICE.