What was found
AIRCRAFT WAS BROUGHT IN FROM OFFSHORE. DURING A DAILY INSPECTION SOME WORKING AND MISSING RIVETS WERE FOUND ON THE TAIL BOOM. A THROUGH INSPECTION WAS PERFORMED ON THE TAIL BOOM ATTACHMENT FITTING. TAIL ROTOR DRIVE TRAIN, TAIL ROTOR GEAR BOX CASTING, TAIL ROTOR GEAR BOX HOUSING, INCLUDING A COMPLETE TAIL BOOM STRUCTURE INSPECTION AND TAIL ROTOR BALANCE CHECK. FOUND A CHAFE ON THE TAIL BOOM SKIN THAT MEASURED .275 IN LENGH AND A DEPTH OF .020. THE TAIL ROTOR BALANCE VIBRATION WAS ALSO FOUND TO BE HIGH 5.31 IPS, AND THE TAIL ROTOR WAS CHANGED.