As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 3661, CREW REPORTED THE LANDING GEAR DID NOT RETRACT AFTER TAKE OFF. ELECTED TO RETURN TO DEPARTURE AND LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. PERFORMED GENERAL VISUAL INSPECTION OF LANDING GEAR AUXILARY ASST VALVE AND BYPASS VALVES AND BYPASS VALVES. NO VISUAL DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.