What was found
MCN - DURING C24 CHECK DISCOVERED 6 CRACKS, .189 INCHES LONG, ON THE BOTTOM OF THE NR 4 SLAT SKIN BELOW THE OUTBOARD AUXILIARY TRACK FROM SS 80R TO SS 100R. MAINTENANCE REMOVED DAMAGED AREA OF SKIN ON THE NR 4 SLAT IAW BOEING 737-300 SRM 57-43-01-2R6. FABRICATED FILLER AND DOUBLER IAW BOEING 737-300 SRM 57-43-01-2R6. INSTALLED FABRICATED REPAIR PARTS ON THE NR 4 SLAT SKIN BELOW THE OUTBOARD AUXILIARY TRACK FROM SS 80R TO SS 100R IAW BOEING 737-300 SRM 57-43-01-2R6.