As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING C-18 CHECK, 4 EACH 3/8 INCH CRACKS WERE FOUND IN NR 4 SLAT LOWER SKIN BETWEEN SLAT STA 42 - 78. MAINTENANCE CUTOUT DAMAGE IN NR 4 SLAT LOWER SKIN; FABRICATED A FILLER AND SPLICE PLATE; INSTALLED REPAIR PARTS IAW B737-300 SRM 57-43-01, FIG 206.