What was found
(CAN) EN ROUTE, THE FLIGHT CREW NOTICED THE PORT AND STARBOARD HYDRAULIC FLOW LIGHTS ON. THE MAIN HYDRAULIC SYSTEM PRESSURE WAS SEEN TO BE FALLING. AIRCRAFT LANDED OK. PORT HYDRAULIC PRESSURE LINE FROM THE PORT EDP HAD FRACTURED AT THE INLET TO THE HIGH PRESSURE FILTER ALLOWING THE LOSS OF FLUID. THE FRACTURE COULD NOT BE SEEN UNLESS THE LINE WAS REMOVED. FRACTURE WAS UNDER THE 'B' NUT. NEW LINE INSTALLED.