As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TUNNEL ASSEMBLY PN 12412020-1 AFT OF STA 108.0 AFT UPPER CORNER. THE CORRODED AREA IS BELIEVED TO BE CAUSED BY THE ENGINE EXHAUST PIPE EMISSIONS. SUBMITTER SUGGESTED A LONGER TAILPIPE SO AS TO GET EXHAUST EMISSIONS AWAY FROM BELLY OF AIRCRAFT. INSPECTION OF LIKE MODEL AIRCRAFT REVEALED SIMILAR CORROSION. AIRCRAFT TT 5,052.5 HOURS.