As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN GEAR WAS RETRACTED AFTER TAKEOFF, ALL GEAR RED LIGHTS REMAINED ILLUMINATED. THE AIRCRAFT WAS RETURNED TO GIG WHERE IT LANDED WITHOUT INCIDENT. THE LANDING GEAR WAS SWUNG SEVERAL TIMES AND THE FAILURE COULD NOT BE DUPLICATED. THE AIRCRAFT HAD A BRIEF HISTORY WITH THIS ANOMALY. THE PROXIMITY CONTROL SWITCH UNIT WAS REMOVED AND REPLACED AS A PRECAUTIONARY MEASURE.