What was found
IN VFR CRUSE FLIGHT WITH ATC, THE PILOT REPORTED HEARING A LOUD BANG AND A SLIGHT ENGINE VIBRATION. A PRECAUTIONARY LANDING WAS MADE, INSPECTION OF THE AIRCRAFT REVEALED THE PROPELLER SPINNER HAD FAILED AND HAD DEPARTED THE AIRCRAFT, AND PORTIONS OF THE FIBERGLASS SPINNER WERE IN PLACE UNDER ATTACHMENT SCREWS.