As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TROUBLESHOOT VIBRATION WHEN FLAPS FULL EXTEND. FOUND WING TO FUSELAGE PANEL 193AT SEAL INSTALLED BACKWARDS AND NOT CONTACTING WING SURFACE PER MM. ALSO SEAL RETAINER INSTALLED INCORRECTLY. REPOSITIONED SEAL AND INSTALLED RETAINER CORRECTLY FOUND PANEL 194AT SEAL WORN AND INCORRECTLY INSTALLED. REPLACED SEAL.