As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING STRUCTUAL REPAIR OF ENGINE DECK. CORROSION WAS NOTICED ON THE RIGHT LONGERON RUNNING ALONG THE RIGHT SIDE OF THE ENGINE PAN. IT WAS NOTICED THAT RED DYE PENETRANT WAS COVERING THE AREA OF CORROSION . SOMEONE AT A PRIOR DATE HAD INSPECTED THE AREA AND DID NOT CLEAN THE PENETRANT OFF WELL. THIS WE THINK CAUSED THE CORROSION OF THE LONGERON. THE LONGERON WAS OUT AT LIMITS SO IT WAS REPLACED.