As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT MAIN LANDING GEAR WOULD NOT RETRACT WITH HANDLE UP, RED GEAR LIGHTS, WITH A VIBRATION IN THE AIRFRAME. RETURN TO FIELD. ADJUSTED LEFT MAIN GEAR ACTUATOR IAW EMB MM 32-32-10. OPS CHECK GOOD. PERFORMED GEAR SWING WITH NO DEFECTS NOTED.