As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INSPECTION FOUND CORROSION ON INTERNAL DOUBLER BTW STGR 28RH TO STGR 28LH AT STA 500C TO 500D (C1). TRIPPLER (INTERNAL TOP DOUBLER) BTW STGR 28RH TO STGR 28LH AT STA 500C TO 500D WAS REPLACED PER GOGO DWG P20196 REV. C NOTE 3 AND B737-900ER SRM 51-40-02-0G.