As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THE PILOT REPORTED THAT DURING THE LAST STAGE OF CRUISE AND DURING DESCENT, THEY HAVE EXPERIENCED A REPETITIVE RAPID FLUCTUATION AND TORQUE DROP OF THE ENGINE INSTALLED ON THE LT POSITION WITH YAW MOVEMENT OF THE ACFT. UNEVENTFUL LANDING WAS MADE. TORQUE FLUCTUATION COULD NOT BE REPLICATED ON GROUND DURING ENGINE RUN. TROUBLESHOOTING IS IN PROGRESS.