As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHIP 9538 -ATB/GEAR/DE- THE AIRCRAFT WAS RETURNED TO THE DEPARTURE AIRPORT AFTER THE LANDING GEAR WOULD NOT RETRACT AFTER TAKEOFF. THE FLIGHT CREW DECLARED AN EMERGENCY WITH ATC. THE LANDING WAS UNEVENTFUL. CORRECTIVE ACTION: MAINTENANCE DISCOVERED THE GROUND SENSING MECHANISM WAS OUT OF ADJUSTMENT. AFTER BEING RE-ADJUSTED THE GROUND SENSING SYSTEM CHECK GOOD AND ALL GEAR SWINGS WERE NORMAL. (LP #4294462)