What was found
ON TAKEOFF AT CLIMB OUT, PILOT HEARD LOUD BANG FOLLOWED BY ROUGH ENGINE, DECLARED EMERGENCY AND LANDED WITHOUT FURTHER PROBLEMS. WITH OIL LEAKING FROM COWL, VISUAL INSPECTION NOTED HEAD SEPARATED FROM NR 6 CYLINDER. WITH COWL REMOVED AND CYLINDER OFF, IT WAS OBVIOUS THE CYLINDER HAD BEEN PARTIALLY CRACKED FOR SOME TIME. (SO05200410648)