What was found
(CAN) ON APPROACH TO WHEN FLAP 2 SELECTED THE CREW OBSERVED RAPID DECREASE IN A HYDRAULIC SYSTEM. HYDRAULIC LEAK/LOSS OK. LIST CARRIED OUT. MANUAL GEAR EXTENSION PERFORMED, AIRCRAFT LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS TOWED FROM THE RUNWAY TO THE HANGAR WHERE INVESTIGATION FOUND NR 4 SLAT ACTUATOR FAILED. THE CYLINDER WAS FRACTURED AT THE END CAP THREAD. THE ACTUATOR WAS REPLACED, BOTH A PUMPS REPLACED, AIRCRAFT RETURNED TO SERVICE.