As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INSPECTION, FOUND WING WALK DOUBLER RIBS CRACKED. THREE OF THE RIBS WERE CRACKED AT OUTBOARD EDGE. SUSPECT CAUSE WAS HIGH TOTAL TIME AND POSSIBLY STRESS INDUCED DURING FORMING OF STIFFENER RIBS. SUBMITTER STATED THIS SEEMS TO BE A COMMON OCCURRENCE ON PIPER PA28 SERIES WITH AT LEAST 4,000 HOURS.