What was found
(CAN) DURING HOVER AFTER 18 MINUTES OF FLIGHT, THIS LOGGING HELICOPTER DEVELOPED A STIFFNESS OF CYCLIC AND THEN COLLECTIVE PITCH. SLINGING WAS ABORTED AND PRECAUTIONARY LANDING WAS CARRIED OUT. AFTER FURTHER INVESTIGATION, IT WAS DISCOVERED THAT THERE WAS METALLIC MATERIAL IN THE FIRST STAGE HYDRAULIC PUMP AND SUBSEQUENT DOWNLINE SYSTEM INCLUDING AFT SERVO BANK. CONSEQUENTLY, AFCS SERVO AND ALL COMPONENTS OF THE FIRST STAGE HYDRAULIC SYSTEM WERE REPLACED. THE AIRCRAFT WAS THEN GROUND AND FLIGHT TESTED.