What was found
WHILE IN FOR D-CHECK, MAINTENANCE FOUND WEB CORRODED AT STA 860, WHERE CENTER WING BOX MEETS WITH W/W PRESSURE PANEL BETWEEN RBL 24, 2ND AND 3RD SEAT TRACK FROM RT SIDE OF FUSELAGE. MAINTENANCE REPAIRED WEB IAW SRM 53-2-0, FABRICATED AND INSTALLED VERTICAL STIFFENER AND END CLIP PER SRM 53-1-0.