As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(PIREP) JUST AS THE GEAR FULLY RETRACTED, THE NR 1 ENGINE TORQUE DROPPED 10 PERCENT, ACCOMPANIED BY A LOW HUMMING NOISE. ALL OTHER INDICATIONS NORMAL, NOISE CEASED AFTER LANDING.MECHANIC PERFORMED ENGINE MAINTENANCE RUN IAW MM 72-00-00 PG. 201. NO DEFECTS NOTED.(TEST FLIGHT) POST MAINTENANCE CHECK FLIGHT SATISFACTORY.