As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING THE WINGLET MOD, A CRACK WAS FOUND ON THE FWD SECTION OF STRINGER 12 AT APPROXIMATELY WSTA 620. THE CRACK IS LOCATED IN THE VERTICAL LEG OF THE STRINGER BELOW THE START OF THE RADIUS AND RUNS IB/OB. CRACK REPAIRED PER ERA 483437-14.