What was found
DURING AN ANNUAL INSPECTION A RUBBING NOISE WAS HEARD DURING THE AILERON MOVEMENT. INSPECTION IN THE LEFT WING, WING STATION 70.85 (RIB OUTBOARD OF THE FLAP ACTUATOR ROD), THE AILERON CABLES TRAVEL THROUGH AN OPENING IN THE RIB. A PIECE OF PHENOLIC IS RIVETED IN THE OPENING FOR THE CABLES TO PASS OVER (OEM INSTALLED PHENOLIC). THE AILERON BALANCE CABLE WAS FRAYED IN THE AREA THAT PASSED OVER THE PHENOLIC BLOCK. CABLE TENSION WAS WITHIN THE MANUFACTURER'S LIMITS. THE CABLE WAS REPLACED.