As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA - AIRCRAFT RETURNED TO FIELD WHEN AFTER TAKEOFF, THE GEAR FAILED TO RETRACT. MAINTENANCE INSPECTED THE AIRCRAFT AND PERFORMED EXTENSION AND RETRACTION OPERATIONAL AND FUNCTIONAL CHECKS IAW DHC MM 32-30-00-720-801. NO PARTS WERE CHANGED AND NO DEFECTS WERE NOTED. COULD NOT DUPLICATE. AIRCRAFT WAS RETURNED TO SERVICE.