As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING MX, EXTENSIVE CORROSION WAS FOUND COMMON TO THE INTERNAL DOUBLER AT THE AFT LAVATORY SERVICE PAN. CORROSION WAS REMOVED IAW SRM & AREA BEYOND ALLOWABLE LIMITS WERE CUT OUT. A TITANIUM REPAIR DOUBLER WAS INSTALLED TO RESTORE STRUCTURAL STRENGTH IAW EA 255445.