What was found
DURING A MAST NUT TORQUE CHECK, A MECHANIC NOTICED EXCESSIVE AXIAL PLAY IN MAIN ROTOR MAST. UPON MEASURING PLAY, IT WAS FOUND TO BE OUT OF LIMITS AND TRANSMISSION WAS SENT TO OVERHAUL SHOP FOR EVALUATION. TRANSMISSION WAS INSPECTED AND THIS BALLBEARING WAS FOUND CRACKED THROUGH ON THE OTHER RACE. EUROCOPTER WAS CONTACTED AND BEARING WAS REPLACED. MAST AXIAL PLAY WAS FOUND WITHIN LIMITS IAW BK117 REM 108 RU 7 AFTER BEARING REPLACEMENT.