As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CORROSION FOUND ON LOWER TEE STRINGER AT APU INLET TORQUE BOY RT SIDE. CORROSION ON LOWER TEE STRINGER WAS BLENDED OUT AND FOUND BEYOND ALLOWABLE IAW B737 400 SRM 53 80 13. REMOVED TEE STRINGER AND INSTALLED NEW PART IAW B737 400 SRM 51 40 02.