What was found
AT D CK, NR 4 SLAT OUTBOARD HOOK CAVITY IN WING IS CRACKED AT AFT OUTBOARD CORNER. STOP DRILLED CRACK AT NR 4 SLAT OUTBOARD HOOK CAVITY PER B727 SRM 51-10-1, VISUALLY INSPECTED, NO FURTHER CRACK NOTED. INSTALLED REPAIR AT NR 4 SLAT OUTBOARD HOOK CAVITY PER B727 SRM 57-30-4 AND 51-30-2. REF: N/R 1653.