What was found
IN-FLIGHT 2 OR 3 MINUTES PRIOR TO LANDING, A SEVERE VIBRATION AND LOUD NOISE WAS FELT AND HEARD. THE AIRCRAFT LANDED. IT WAS DISCOVEREDTHE AFT OIL COOLER BLOWER SHAFT AFT BEARING HAD FAILED AND COME APART. THE INNER RACE AND BALL BEARINGS DAMAGED THE IMPELLER. THE OUTER RACE AND HANGAR DAMAGED THE BLOWER SHAFT. POSSIBLE CAUSE WAS OVERHEATING. BEARING WAS LUBRICATED APPROXIMATELY 80 HRS PRIOR TO OCCURRENCE. REPORTED TO BELL HELICOPTER PRODUCT SUPPORT FOR INVESTIGATION. BEARING WAS NEW STYLE TYPE (BLUESEAL).(X)