As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) PILOT NOTICED UNUSUAL VERTICAL VIBRATION IN HOVER AND LANDED IMMEDIATELY. MAINTENANCE DICOVERED BLUEMAIN ROTOR ROTATING CONTROL ROD LOWER ROD END BEARING HAD EXCESSIVE PLAY. THIS WASDUE TO 1/3TH OF THE SPHERICAL BEARING OUTER RACE WORN AWAY. SPHERICAL BALL BEARING HAD BEEN NEARLY CONTACTING THE ROD END. ROD END REPLACED, A/C TRACKED AND RETURNED TO SERVICE.