As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON APPROACH, THE LANDING GEAR FAILED TO EXTEND WHEN SELECTED. EMERGENCY EXTENSION CARRIED OUT. LANDED SAFELY. INVESTIGATION FOUND THE CANISTER OF THE HYDRAULIC FILTER ON THE LT ENGINE FIREWALL HAD CRACKED IN THE THREADS ALLOWING FLUID TO BE PUMPED OVERBOARD. CANISTER REPLACED, FLUID REPLENISHED, GEAR SWINGS AND GROUND RUN CARRIED OUT. OPERATION NORMAL.