As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAIN LANDING GEAR WOULD NOT LOCK IN THE DOWN POSITION. AFTER AN UNEVENTFUL LANDING, AIRCRAFT WAS PLACED ON JACKS AND THE DOWNLOCKS WERE FOUND WITHOUT LUBRICATION AND STUCK IN THE UNLOCKED POSITION. IT WAS FOUND THE OPERATOR REQUIRES THE LANDING GEAR TO BE CLEANED WEEKLY; THUS, REMOVING ALL LUBRICANT. IT IS RECOMMENDED THAT ALL LANDING GEAR PIVOT POINTS BE PROPERLY LUBED AFTER EACH CLEANING.