As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A SCHEDULED MAINTENANCE, LEVEL 2 CORROSION WAS DISCOVERED ON NR 2 ENGINE INBOARD COWLING. CORROSION WAS LOCATED UNDERNEATH THE FIRE SEAL AREA THROUGHOUT THE FORWARD AND AFT SECTION. REMOVED FIRE SEAL FOR ACCESS TO THE CORRODED SECTION OF SKIN. REMOVED THE CORRODED SECTION OF SKIN, FABRICATED AND INSTALLED NEW SECTION OF SKIN IAW SRM. FIRE SEAL WAS THEN REATTACHED TO ENGINE COWLING.