What was found
HEAVY CORROSION FOUND DURING PHASE INSPECTION ON WING MAIN SPAR LOWER CAP AREA WHERE IT PASSES THROUGH THE LT FUSELAGE PRESSURE VESSEL. CAUSE OF CORROSION WAS DUE TO MOISTURE BEING TRAPPED UNDERNEATH DETERIORATING SEALANT THAT SEALS THE PRESSURE VESSEL. A MAJOR REPAIR RESULTED BY REMOVING ALL CORROSION, BLENDING THE SPAR CAP AND RETREATING WITH PRIMER AND PAINT AS NECESSARY. THE ACFT MFG ASSISTED IN THE REPAIR PROCESS, AND DEVELOPED AND APPROVED THE REPAIR PROCEDURES.