As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SIGNIFICANT AIRFRAME VIBRATION IN LEVEL FLIGHT AND ACCELERATING AT 12000'. VIBRATION CAME ON AT BETWEEN 270-290 KNOTS. FELT A LIGHT RUMBLE IN THE YOLK AT 210 KNOTS. REMOVED RT AILERON PANEL. INSTALLED A SERVICEABLE RT AILERON PANEL ASSEMBLY. WORK PERFORMED IAW AMM 57-60-05, POST-MAINTENANCE CHECKS COMPLETE AND CHECKED GOOD.