As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED THAT DURING THE CLIMB, THE LT PROPELLER RPM RATE BECAME UNCONTROLLABLE. THE PILOT ELECTED TO RETURN TO THE DEPARTURE AIRPORT AND LANDED SAFELY. UPON MX INSPECTION, THE C/A WAS TO RESECURE THE LT PROP CONTROL CABLE TO THE LT PROP GOVERNOR.