As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE A/C WAS IN FOR HEAVY CHECK FOUND LEVEL 2 CORROSION ON INTERNAL SIDE OF WASTE DRAIN BOX STRAP FWD LOWER SLIDE FLANGE. MX REPLACED WASTE DRAIN SERVICE BOX IAW EMB 170 SRM. A/C REMAINS IN HEAVY CHECK FOR COMPLETION P/N 170-65078-403.