As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRFRAME VIBRATION FELT DURING CLIMB CRUISE DESCENT. COMPLETED VIBRATION REPORTING CHECKLIST. CREW REPORTS VIBRATION WAS MORE NOTICEABLE DURING CLIMB WHEN A-P WAS OFF & DECREASED WHEN A-P WAS ON. CREW REPORT ALMOST NOT DETECTABLE DURING DESCENT. HAVE VERIFIED VIBRATION ISSUE TO BE ELEV SERVO OSCILLATION. SEE LOG006 FOR SERVO REPLACEMENT.