As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON GEAR EXTENSION, THE LEFT HYDRAULIC SYSTEM QUANTITY DECREASED TO ZERO AND A "L HYD SYS PRESS" MESSAGE WAS DISPLAYED. FLIGHT LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE LEFT MAIN LANDING GEAR DOWNLOCK RETURN LINE. OPERATIONAL TESTS WERE SATISFACTORY.