As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN)DURING INSPECTION UPWARD PRESSURE WAS APPLIED TO THE WING AND A LOUD CRACKING NOISE WAS HEARD. THE SOURCE WAS TRACED TO THE UPPER WING STRUT ATTACH RIVETS WHICH HAD BECOME LOOSE. SUBMITTER REBUCKED TH E RIVETS AND RETURNED THE AIRCRAFT TO SERVICE.