As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN DECENDING FROM 14K FEET TO 12K FEET, CREW ACTIVATED SPD MODE TO ALLOW CONTROL RATE VIA ENGINE POWER. ONCE ENGINE TORQUE WENT BELOW 10PSI CREW HEARD LOUD BANG FROM FRONT OF AIRCRAFT AND A THUD WAS FELT. NO ENGINE INSTRUMENTS INDICATING ANYTHING WAS WRONG AND NO CASS MESSAGE.