As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN GEAR HANDLE WAS SELECTED DOWN DURING APPROACH 3 RED LIGHTS ILLUMINATED WITH THE LANDING GEAR INOPERATIVE CAUTION LIGHT ALSO ILLUMINATED. THE QRH WAS PERFORMED AND THE LANDING GEAR EXTENDED. THE LANDING GEAR SELECTOR VALVE WAS REPLACED IAW Q400 AMM 32-31-06. ALL FUNCTIONAL CHECKS WERE SATIFACTORY AND AIRCRAFT WAS RETURNED TO SERVICE.