What was found
DURING CRUISE FLIGHT, THE PILOT REPORTED A LOUD BANG FOLLOWED BY EXCESSIVE VIBRATION, INCREASED POWER TO FULL TO MAINTAIN ALTITUDE AND MADE A WELL-EXECUTED,, PRECAUTIONARY LANDING. AFTER SHUTDOWN THERE WAS A LARGE OIL PUDDLE DEVELOPING UNDER THE AIRCRAFT. AIRPLANE COWL REMOVED AND NR 4 CYLINDER WAS FOUND TO HAVE THE TOP HALF SEPARATED FROM THE BOTTOM. THIS CYLINDER REPORTED TO BE IN SERVICE LESS THAN A YEAR. THE CYLINDER HAS THE CASTING NR AEL85099 WHICH IS NOT SUBJECT TO AD2006-12-07 OR SB NR 05-8. ENGINE HAS (3) OTHER CYLINDERS WITH THE SAME CASTING NUMBER INSTALLED. IT IS ESTIMATED THAT ENGINE LOST 2.5 QUARTS OF OIL DURING THE FEW MINUTES BETWEEN THE SEPARATION AND THE SHUTDOWN. MECHANIC SUGGEST FAA L