As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WING STRINGERS FOUND WITH ELONGATED HOLES AT THE PILOT HOLES LOCATIONS OF THE OUTER WING SKIN, TOP & BOTTOM. ROOT CAUSE INVESTIGATION REVEALED THAT THE CONDITION IS CAUSED DURING DRIVEMATIC HOLE DRILLING FOR FINAL RIVET INSTALLATION. AFFECTED RANGE OF A/C 4001-4447, 4448-4450, REWORKED IN-HOUSE.