As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY MAINTENANCE CHECK CORROSION SIGNS UNDER ACOUSTIC LINER ENGINE #2 POSITION 3 AND 6 O'CLOCK (REPIAR). CORROSION IN ACOUSTIC INNER LINER ENGINE #2 POSITION 3 AND 6 O'CLOCK WAS CLEANED IAW B747-400F AMM 51-00-53. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.