As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, CREW FELT A VIBRATION. CREW RETURNED FOR INSPECTION AND EVALUATION. AC LANDED UNEVENTFULLY. AIRCRAFT WAS INSPECTED. FOUND T/R LOCK ACCESS PANEL MISSING FROM LT IB ENGINE. AC WAS INSPECTED FOR DAMAGE OR DEFECT- NONE NOTED. NEW PANEL INSTALLED. AC WAS RETURNED TO SERVICE. (K)