What was found
PILOT REPORTED, DURING CLIMBOUT FROM SYR LEFT HYD SYSTEM QTY DECREASED TO NEAR ZERO AFTER GEAR AND FLAP RETRACTION. CONTINUED FLIGHT TO SDF. SDF RESCUE VEHICLES RESPONDED DUE TO THE DECLARED EMERGENCY. FLIGHT WAS UNEVENTFUL EXCEPT FOR LT HYD FAILURE. FOUND LT MLG DOWNLOCK ACTUATOR UP LINE RUPTURED. REPLACED HYD LINE ASSY, INSPECTED AND REPLACED CASE DRAIN FILTERS AND SERVICED LEFT HYD SYS.