As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THE ROTOR SYS WAS FOUND TO BE INCREASING IN VIBRATION. CHECKED THROUGH THE SYSTEM AND FOUND THE BEARINGS WHEN PURGED OF GREASE WERE SHOWING FINE METAL PARTICLES. CARRIED OUT A WEIGHTED ROTATIONAL TEST ON PITCH HOUSINGS AND FOUND THE BEARINGS TO BE A BIT ROUGH. THIS LED ME TO REPLACE THE PITCH HOUSING BEARINGS ON ALL 3 PITCH HOUSINGS.