What was found
I/B FLAPS FAILED TO EXTEND BEYOND 10 UNIT. ALT EXTENSION FAILED. GRD CK FOUND RT I/B FORE & MID FLAP DAMAGE & NR 5 MAIN CARRIAGE SPINDLE BROKEN. REPLACED RT I/B FORE/MID FLAP. REPLACED NR 5 MAIN CARRIAGE. PERFORM I/B FLAP ADJ/TEST. REPLACED DFDR. NR 6 CARRIAGE REMOVED & FOUND CORROSION PITTING. CARRIAGES REPLACED. FRACTURED CARRIAGE SENT TO BOEING. FRACTURE INITIATED FROM CORROSION PITTING OD SURFACE & PROPAGATED. PRESENCE OF HIGH CONCENTRACTION OF CHLORINE ELEMENT FOUND ON FRACTURE SURFACE MIGHT HAVE CONTRIBUTED TO STRESS CORROSION CRACKING. ALL OVERHAUL PROCEDURES & SHOP WORKSHEETS REVIEWED & REVISED TO COMPLY W/OHM. T/E FLAP CARRIAGE MUST BE REPEAT OVERHAULED NOT TO EXCEED 30000 FH OR 8 YRS.