As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CORROSION WAS FOUND ON RIGHT WEB AND STRINGER. REPLACED THESE PARTS LAST YEAR FOR SAME REASON. THE REPLACED HAD BEEN PAINTED WITH EXPOXY PRIMER PRIOR TO INSTALLATION. IT HAS BEEN NOTED THAT ALL PLACES THAT CORRODED BOTH TIME HAD BEEN IN DIRECT CONTACT WITH UPHOLSTERY THAT WAS INSTALLED 2.5 YEARS AGO. SUSPECT FABRIC WAS SPRAYED WITH SOME FORM OF FIRE RETARDENT THAT IS CORROSIVE.