What was found
DURING HEAVY MAINTENANCE CENTER WING UPPER PANEL CORRODED AT LH APPROX STA 1226, XCW 22.5 AT S-15. 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 1226, XCW 22.5 AT S- 15 IAW MD-11 BOEING MESSAGE: WGN-WGN-25-0035-04C. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.