What was found
FAIRLEADS IN RUDDERVATOR TRIM TAB CNTRL CABLE SYS ARE CRACKING UPON INSTALLATION, POSSIBLY DURING FLIGHT. BUTTON-HEAD RIVETS ARE INTERFERING WITH INSTALLATION, CAUSING CRACKS TO FORM IN (TANG) OF FAIRLEADS. CABLE TENSION USED IN RUDDERVATOR TRIM TAB CABLES IS A FACTOR IN CRACKING. A LOOSENING OF RUDDERVATOR TRIM TAB CNTRL CABLES IS NECESSARY DURING INSTALL, FOLLOWED BY RIGGING TO VERIFY PROPER CABLE TENSION. A SMALL AMOUNT OF FILING ON BACK OF (TANG) OF FAIRLEAD FOR CLOSE TOLERANCE OF RIVETS THAT HOLD NUTPLATE FOR MOUNTING OF FAIRLEAD. EITHER A NEW MATERIAL NEEDS TO BE EXPLORED FOR MAKING FAIRLEADS MORE DURABLE, OR A MAINT NOTE NEEDS TO BE MADE ON PROPER INSTALLATION OF FAIRLEADS TO PREVENT CRACKING. (K)