As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) LANDING GEAR FAILED TO RETRACT. THE GROUND SENSING RELAY AND GROUND SENSING MODULE WERE CHANGED BUT THE DEFECT REMAINED. DURING TROUBLESHOOTING THE DEFECT DISAPPEARED. A THOROUGH SERVICEABILITY CHECK WAS CARRIED OUT AND THE AIRCRAFT RETURNED TO SERVICE.