What was found
DURING HEAVY MAINTENANCE: CORROSION FLOOR STRUCTURE LOC. BTW FR 41 TO FR 42 AND BTW -Y1292 TO -Y1732 EXTERNAL SKIN UPPER SURFACE CENTER WING BOX IN PASSENGER CABIN; (RESOLVED ON W/O: 1200126 TASKCARD: NR-00039 ) REF AEM NR# 2023-68843 FOR ALL WORK ACCOMPLISHED REPAIR OF CORROSION DAMAGE ON CTR WING BOX UPPER SKIN PANEL UPPER SURFACE AT -Y1292 AND BETWEEN STIFFENER 16-17 IAW AEM EA# 57-0040-23 REV 0 ( COVER AND PART #1-5) AND AIRBUS RDAF REF 81174227/003/2023#A AND EC # A23-220-01.