As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING APPROACH AND UPON SELECTING "GEAR DOWN", THE NLG SHOWED ONLY "RED" (UNSAFE) LIGHT. EMERGENCY WAS DECLARED. ALTERNATE EXTENSION METHOD WAS ACCOMPLISHED SATISFACTORY. GROUND MX CREW R & R THE NLG SEQUENCE VALVE. LANDING GEAR EXTENSION AND RETRACTION SYS CHECKED SATISFACTORY, ACFT RETURNED TO FLIGHT STATUS.