As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLT - FLT 1604 - AFTER TAKEOFF, CREW GOT WARNING CHIME THAT AIRCRAFT WAS STILL ON THE GROUND. GND/FLT MESSAGE APPEARED ON MFDU. CREW ALSO WAS UNABLE TO GET ANY OF THE GEAR TO RETRACT. FLIGHT RETURNED TO CLT WHERE LANDING WAS WITHOUT FURTHER INCIDENT. MAINTENANCE ADJUSTED THE RIGHT MAIN GEAR GND/FLT SWITCH. (M)