As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE FLIGHT, AT FL 250, NR 1 ENGINE HAD A VIBRATION STARTING AT 57 PERCENT TORQUE AND INCREASED AS TORQUE INCREASED. VIBRATION STOPPED BELOW 57 PERCENT TORQUE. ALL OTHER ENG INDICATIONS NORMAL. DIVERTED FLIGHT AND ACCOMPLISHED AN UNEVENTFUL LANDING. R & R NR 1 PROP ASSY IAW MX 6610003 AND 6610004. C/W ENG RUNS POST INSTALLATION OF PROP ASSY IAW MX 6710006. RAN NR 1 ENG FROM TORQUE OF 10 PERCENT TO 90 PERCENT NO ABNORMAL VIBRATIONS NOTED NO OTHER DEFECTS NOTED. RETURNED TO SERVICE.