What was found
AFTER REMOVAL OF CENTER COCKPIT WINDSHIELD, PN MY20261-10-4, WHICH WAS BEING REPLACED DUE TO EDGE DELAMINATION BY CUSTOMER REQUEST (NOTE: EDGE DELAMINATION WAS WITHIN LIMITS PER MANUFACTURER'S MM), LOWER WINDSHIELD SEAL AREA OF FRAME HAD SEVERE INTERGRANULAR CORROSION CAUSING EDGE OF FRAME TO FLAKE. WHILE BLENDING OUT CORROSION, TRAILS, BLENDING PROTRUDED THROUGH FRAME AT LOWER SEAL AREA RADIUS TO UNPRESSURIZED SIDE OF FRAME. (APPROXIMATELY 1 INCH LONG HOLE). ALSO, SEVERAL OTHER AREAS OF CORROSION BLENDED THROUGH APPROXIMATELY 50 PERCENT TO 65 PERCENT OF MATERIAL THICKNESS. CORROSION CANNOT BE VISUALLY SEEN WITHOUT REMOVAL OF WINDSHIELD.