As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT NOTICED THAT THE LT TORQUE INDICATION SLOWLY AND CONTINUALLY DECREASED. WHEN POWER ADJUSTMENTS PRODUCED NO EFFECT AND ADVERSE YAW CONFIRMED POWER LOSS THE PILOT FEATHERED THE PROP AND SHUTDOWN THE ENGINE. SUBSEQUENT INVESTIGATION DETERMINED THAT THE FCU HAD FAILED.