As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE IN-FLIGHT, NR 1 TURBOCHARGER FAILED. THE AIRCRAFT LANDED WITHOUT DAMAGE. UPON INSPECTION BY MAINTENANCE, DISCOVERED TURBO MAIN SHAFT HAD BROKEN AND WHEEL ON THE EXHAUST SIDE WAS MISSING. IT APPEARS TO HAVE GONE OUT THE OVERBOARD STACK. THE OTHER WHEEL WAS STILL IN THE TURBO. CAUSE: UNKNOWN.