As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A TOUR FLIGHT, SMOKE WAS SEEN IN THE COCKPIT AND A BURNING SMELL WAS NOTED. THE AIRCRAFT RETURNED TO THE AIRPORT WITHOUT INCIDENT. AFTER SHUTDOWN, IT WAS DISCOVERED THAT THE AIR CONDITIONING COMPRESSOR BELT HAD SHREDDED. THE AIR CONDITIONING BELT AND A/C OOMPRESSOR WERE REPLACED AND NO FURTHER ISSUES FOUND