As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN FLIGHT THE INSTRUMENT VACUUM SYSTEM FAIL. THE AIRCRAFT RETURNED TO MAINTENANCE AND AN INSPECTION OF THE SYSTEM FOUNDED THAT THE ROTOR HAD FROZEN UP AND THE SHAFT HAD SHEARED. PUMP WAS REMOVED AND A NEW PUMP INSTALLED. OPERATIONAL CHECK OF THE SYSTEM CHECKED NORMAL.