As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA - UPON SELECTION OF GEAR UP, AFTER TAKEOFF, GEAR 3 GREEN LIGHTS REMAINED ILLUMINATED, 3 RED INDICATORS ILLUMINATED AND GEAR HANDLE ILLUMINATED. RAN 'GEAR WOULD NOT RETRACT' AND 'ALT GEAR EXTENSION' CHECKLIST. RETURNED TO THE FIELD AND ACCOMPLISHED A UNEVENTFUL LANDING. REMOVED AND REPLACED NLG WOW HARNESS. ALL CHECKS GOOD. RETURNED TO SERVICE.