As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLT 3865 - ON APPROACH TO IAH, LANDING GEAR WOULD NOT EXTEND. CREW FOLLOWED EMERGENCY EXTENSION PROCEDURES AND THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE LANDING GEAR SELECTOR VALVE AND PERFORMED OPERATIONAL CHECKS PER ATR-42 MM PROCEDURES, ALL SYSTEM CHECKS NORMAL. AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE. (X)