As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT CARGO L/H TRANSITION HAS AREAS OF CORROSION STA 727A TO 847. GROUNDED - YES. REMOVED CORROSION FOUND OUT LIMITS IAW B737-900ER SRM 53-00-53-1A-2 & FABRICATED TRANSITION IAW B737-900ER SRM 53-00-53-2R-5W=1" O=.040" R=.023" L=1" D=.017".