What was found
(CAN) DURING LAST 2 MINUTES OF APPROACH THE RT HYDRAULIC PRESSURE DROPPED OFF. AIRCRAFT LANDED UNEVENTFULLY AND WAS TOWED TO HANGAR. RT HYDRAULIC PUMP WAS REPLACED AND AIRCRAFT GROUND RUN. PRESSURE DID NOT RETURN. FURTHER INVESTIGATION REVEALED AN INTERNAL ACCESSORY DRIVE GEAR FAILURE. VIEWED THROGH THE OIL FILLER NECK SEVERAL GEARS COULD BE SEEN WITH CHIPPED TEETH AND ONE GEAR COULD BE SEEN LAYING HORIZONTALLY.