What was found
DURING A PREFLIGHT INSPECTION, PILOTS NOTICED THE FREEWHEELING UNIT WAS ROUGH WHILE THEY WERE CHECKING FOR ROUGHNESS IAW THE PREFLIGHT CHECK LIST. THEY NOTIFIED OUR MX DEPARTMENT, UPON INSPECTION BY THE MECHANIC WHILE TURNING SHEAVE BACKWARDS HE OBSERVED ROUGHNESS IN THE SHEAVE AND THE ROTOR SYS WAS TURNING BACKWARDS AS WELL. THE SHEAVE MOMENTARILY LOCKED UP AND THEN GAVE WAY AT THE SAME TIME PRODUCING A METALLIC SOUND. IAW TECH SUPORT WE RAN THE HELICOPTER UP TO APPROX 30 PERCENT THE CLUTCH ACTUATOR WAS STILL ENGAGING THEN PULLED THE MIXTURE, THE ROTOR SYS SPUN DOWN AND STOPPED WITHIN APPROX 4 REVOLUTIONS. AT THAT POINT WE DECIDED TO DISASSEMBLE THE CLUTCH AND INVESTIGATE THE PROBLEM. IT APPEARS THAT EITHER THE FWD BEARING FAILED AND MATERIAL FROM THE BEARING DISRUPTED THE CLUTCH OR THE CLUTCH FAILED AND DISRUPTED THE BEARING.