What was found
(CAN) ACM LOUVERED EXHAUST PLENUM REMOVED TO CARRY OUT "F" CHECK PROCEDURE. NOTED AFTER REMOVAL OF LOUVERED PLENUM THAT THE PLENUM WAS CHAFING INTO THE LOWER MAIN SPAR CAP FORWARD FLANGE AT LWS 35-LWS 40. LWS 35 SPAR CAP FLANGE CHAFED TO 0.06 INCH AND DECREASED TO 0 INCHES AT APPROX LWS 40. CHAFE DAMAGE REPAIRED IAW RAYTHEON AIRCRAFT STANDARD REPAIR DRAWING #SR-CO-00018 REV. A. AREA OF LOUVERED PLENUM REMOVED SO NO FURTHER CONTACT WITH SPAR CAP CAN OCCUR. (TC# 20110131010)