As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOTS REPORTED THAT THE LANDING GEAR CIRCUIT BREAKER TRIPPED, THEY OBSERVED 3 GREEN DOWN LIGHTS. PILOTS THEN RETARDED THE LOWER LEVERS BACK WITH GEAR DOWN AND GOT A GEAR HORN, THE C/B THEN POPPED AGAIN. A MANUAL EXTENSION WAS THEN PERFORMED. MX R & R THE LANDING GEAR CONTROL HANDLE IAW MM 32-30-00. GEAR RETRACTION TEST WAS GOOD. NOTE: THIS ACTUALLY OCCURRED DURING A TRAINING FLIGHT.