As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NOTED SEVERE VERTICAL VIBRATION SHORTLY AFTER TAKEOFF THAT INCREASED IN MAGNITUDE. RETURNED AND LANDED. RT AFT M/R SERVO FRICTION FOUND LOW, ADJUSTED PER MM. RT FWD M/R SERVO CAP NUT FOUND SLIGHTLY LOOSE, SECURED. ADJUSTED CYCLIC MIN FRICTION PER MM.