What was found
DURING HEAVY MAINTENANCE CHECK CENTER WING UPPER PANEL CORRODED AT LH APPROX STA 1173, XCW 112 AT S-22. AFTER FURTHER EVALUATION BOEING CERTIFIED THE BLENDED OUT AREA AS A PERMANENT REPAIR AND BEEN COMPLETED WITH ALL THE REQUESTED PROVISIONS AT LH CENTER WING UPPER PANEL APPROX. STA 1173, XCW 112 AT S-22 IAW MD-11, BOEING MESSAGE: WGN-WGN-25-0035-04C. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.