As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LANDING GEAR FAILED TO EXTEND AFTER PLACING THE LANDING GEAR CONTROL DOWN. LANDING GEAR CIRCUIT RELAY CIRCUIT BREAKER TRIPPED AND GEAR HANDLE UNSAFE LIGHT REMAINED ILLUMINATED. THE PILOT PERFORMED MANUAL EXTENSION PROCEDURES AND THE AIRCRAFT LANDED WITHOUT FURTHER INCIDENT. DURING GROUND TROUBLESHOOTING, THE DISCREPANCY COULD NOT BE DUPLICATED. THE HYDRAULIC POWER PACK WAS REPLACED AND THE FLIGHT CREW PERFORMED AN OPERATIONAL CHECK FLIGHT. THE SYSTEM WAS OPERATED IN FLIGHT 3 TIMES, FUNCTIONED NORMAL. NO FURTHER ISSUES.