What was found
DURING C22 MAINTENANCE CHECK AT HAECO AMERICAS, MAINTENANCE REPORTED SEVERE CORROSION DAMAGES ON THE FWD. CARGO LOWER SILL OUTER CHORD (143T8205-3). MAINTENANCE AND CUSTOMER OPTED TO REPLACE THE SUBJECT CHORD AND REQUIRED A SUBSTANTIAL WORK (FASTENERS AND PARTS REMOVAL) FROM BS 412 TO BS 654+44. DUE TO AMOUNT AND SIZE OF STRUCTURES TO BE REMOVED, THE AIRCRAFT REQUIRED TO BE JACK AND SHORED. HAECO AND BOEING ENGINEERING WERE CONSULTED ON REPAIR PROCEDURE. REPAIRED PER ABX-REA-5330-64885-00. VENDOR DID NOT REPORT REPAIR TO ABX AIR. THIS WAS DICOVERED BY AN FAA AUDIT OF THE VENDOR.