As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A NON-ROUTINE, UNSCHEDULED REMOVAL OF THE LEFT ENGINE THRUST STRUT, THE L.P. AIR DUCT MENTIONED WAS REMOVED. AFTER REMOVAL, A HOLE WAS DISCOVERED IN THE DUCT CHAFED BY THE AFT THRUST STRUT ATTACH BOLT HEAD (PN GAB511EB14D40). THIS DEFECT WAS IN SUCH A LOCATION THAT A STANDARD VISUAL INSPECTION WOULD NOT HAVE DISCOVERED THE DEFECT. (X)