What was found
IN FLIGHT EICAS "L HYD QTY" ON WITH ACCOMPANYING DROP IN L HYD QTY ON STATUS PAGE. INSPECTED MIDDLE RUDDER PCU, ELEVATOR DEEL UNIT, RATIO CHANGER, RT YAW DAMP SERVO NO LEAKS NOTED INSPECTED INSIDE VERTICAL FIN FOUND B-NUT FOR LT HYD SYSTEM LINE LOOSE TIGHTENED B-NUT AND PERFORMED LEAK CHECK NO LEAK NOTED CONTD ON 4M. SERVICED LT HYD SYSTEM PER MM 12-12-01 DUE LT HYD SYSTEM LOSS REMOVED AND REPLACED CASE DRAIN, PRESSURE AND RETURN FILTER REMOVED AND REPLACED CASE DRAIN PRESSURE AND RETURN AND ENG PRESSURE FILTER PER MM 29-11-17 LK CK OK. LEFT ENGINE EDP REQUIRES REPLACEMENT DUE LOST QTY OF HYD FLUID REMOVED AND REPLACED NR 1 EDP PER MM 29-11-05 RAN ENGINE. OPS AND LEAK CK OK.