What was found
WING CTR SECTION, UPPER SKIN PANEL, U-17C AND LBL 92 UPPER WING SKIN AND SPLICE: SKIN CORRODED BEYOND SRM LIMITS. DURING FINAL CLOSE UP OF AIR RETURN GRILLS IN THE OVER WING AREA, A FOD INSP WAS CARRIED OUT WITH MIRROR, PRIOR TO INSTALLING THE PANEL. HEAVY CORROSION WAS EASILY NOTED 6" INBD OF THE OPENING, ON THE CTR WING TOP SKIN AND HAD LIFTED THE FUEL BARRIER COATING. ENGINEERING AND OEM CONSULTED FOR REPAIR DESIGN. TI 190140859 REFERS.