As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING A YEARLY INTERNAL WING CORROSION INSP AS REQUIRED BY CHAPTER 5 REQUIREMENTS, EXTENSIVE SPAR/STRINGER/SKIN CORROSION WAS DISCOVERED IN THE INBD SECTION OF THE MAIN TANKS AND THE COLLECTOR TANKS. X-RAY INSP REVEALED UNDISCOVERED SPOTS OF CORROSION BENEATH SECURE PRC WHICH DOES NOT NORMALY REQUIRE REMOVAL. THE ACFT HAS BEEN GROUNDED PENDING ACOMPLISHMENT OF REPAIRS AS DICTATED BY MFG.