As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING A SIMULATED EMERGENCY DESCENT THE PILOT DETECTED AN OVERSPEED OF THE NR 1 ENGINE. EMERGENCY PROCEDURES WERE CARRIED OUT AND THE ENGINE WAS SHUTDOWN AND THE PROPELLER FEATHERED. THE TRAINING MISSION WAS ABORTED AND THE AIRCRAFT LANDED. THE OVERSPEED WAS ATTRIBUTED TO A PINCHED O-RING ON ONE OF THE PROPELLER REGULATING VALVES.