As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 ENGINE N1 FAN VIB PEAKED AT 4.0 DURING CRUISE IN ICING CONDITIONS. ALL INDICATIONS IS NORMAL RANGE UPON LANDING. INSPECTED FAN INLET AND TURBINE, NO DAMAGE WAS NOTED. OPERATED LEFT ENGINE AT VARIOUS POWER SETTINGS FOR 25 MINUTES. LEFT ENGINE N1 VIBS WERE .6. SUBMITTER STATES: SUSPECT ICE ON SPINNER IN FLIGHT WAS THE CAUSE OF THE PROBLEM.