What was found
IMPROPER DEFLECTION OF RUDDER TRIM CABLE AT FS 163 CAUSING, SAWING, AT LIGHTNING PASSTHRU HOLE. THE MAINTENANCE AND PARTS MANUALS DO NOT SHOW THE BRACKET AND PULLEY ASSY IN THIS AREA. WHEN THE PULLEYS ARE REMOVED, THE CABLES REMAIN IN A POSITION FOR ADDITIONAL "SAWING" DAMAGE SUGGESTING IMPROPER DESIGN FOR CABLE DEFLECTION. APPEARS TO HAVE BEEN THAT WAY SINCE THE AIRCRAFT BIRTHDAY. AREA IS DIFFICULT TO ACCESS AND DAMAGE IS NOT EASY TO DETECT DURING VISUAL INSPECTION, DESIGN AND HUMAN FACTOR ISSUES.