As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAKEOFF, ENGINE RPM DECREASED TO 2200 RPM. THE PILOT MADE A SUCCESSFUL LANDING. UPON REMOVING THE TOP COWLING THE PROPELLER CONTROL CABLE BALL JOINT RECEIVER WAS FOUND DISCONNECTED FROM THE RECEPTACLE. THE RETENTION CLIP WAS IN PLACE AND WAS NOT FOUND TO BE DEFORMED OR DISTORTED.