As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE FLIGHT, PILOT AND FLIGHT CREW SMELLED BURNING ODOR AND SAW SMOKE IN THE CABIN OF THE AIRCRAFT. FLIGHT CREW MADE AN UNSCHEDULED LANDING. UPON LANDING, IT WAS DISCOVERED THAT THE COMPRESSOR BELT, PN: 451500003 HAD BURNED OFF OF THE COMPRESSOR PULLEY.