As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FOUND MAIN SPAR LOWER CAP SEVERELY CORRODED. THIS CORROSION WAS FOUND WHERE MAIN SPAR PASSES THROUGH FUSELAGE BENEATH AIR CONDITIONER LOCATION. SUSPECT MOISTURE FROM AIR CONDITIONER COLLECTED ON SPAR CAUSING CORROSION. LOCATION FURTHER IDENTIFIED AS FS 288.0, FROM WS 0.0 TO RT WS 27.0.