As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON LIFTOFF, THE CREW RECEIVED A LANDING GEAR AIR/GROUND FAIL MESSAGE AND THE LANDING GEAR LEVER WAS LOCKED DOWN. THE CREW RETURNED TO KSDF AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE LANDING GEAR ELECTRONIC UNIT, THE NOSE LANDING GEAR WOW PROXIMITY SWITCH, THE HARNESS CONNECTED TO THE NOSE LANDING GEAR WOW PROXIMITY SWITCH, AND THE RIGHT MAIN LANDING GEAR WOW PROXIMITY SWITCH. MAINTENANCE PERFORMED LANDING GEAR SWINGS AND OPERATIONAL CHECKS WERE GOOD WITH NO FURTHER DEFECTS NOTED.