What was found
(CAN) DURING PHASE 6 DETAILED INSPECTION MAINTENANCE FOUND LOOSE FASTENERS, JO-BOLTS AT CENTER HINGE "A" FRAME OF THE RUDDER LOOSE. DURING RUDDER REMOVAL IT WAS FOUND THAT UPPER AND CENTER RUDDER ATTACHING 8 BOLTS WERE SHANKED OUT. IT IS SUSPECTED THAT THE VIBRATION CAUSED THE CENTER "A" FRAME FASTENERS TO WEAR LOOSE, CENTER "A" FRAME TO SPAR ATTACH BOLTS TO LOOSEN UP & THE LOWER TORQUE TUBE ATTACH BOLTS TO WEAR BEYOND LIMITS. ALL HARDWARE REPLACED WITH NEW, RUDDER WAS RE-INSTALLED IAW MM AND THE ACFT WAS RETURNED TO SERVICE.