What was found
(CAN) DURING CRUISE FLIGHT, A TOTAL HYDRAULIC FAILURE WAS ENCOUNTERED, AN EMERGENCY GEAR EXTENSION WAS PERFORMED AND THE AIRCRAFT LANDED WITHOUT INCIDENT. A SUBSEQUENT INSPECTION REVEALED THAT THE HYDRAULIC SYSTEM FLUID LEVEL WAS AT ZERO, CAUSED BY A LEAK AT THE OUTPUT FITTING PIN AN815-65 OF THE LT HYDRAULIC PUMP, FURTHER INSPECTION REVEALED THAT THE O-RING FOR THIS FITTING HAD BEEN PINCHED ON INSTALLATION OF THE HYDRAULIC PUMP THE PREVIOUS DAY. THE O-RING WAS REPLACED, THE HYDRAULIC SYSTEM SERVICED AND THE AIRCRAFT RETURNED TO SERVICE.