What was found
TUBE ASSEMBLY WAS FOUND CHAFED DURING A SCHEDULED INSPECTION OF HYDRAULIC PLUMBING IN TAILCONE. THE TUBE ASSEMBLY WAS REPLACED WITH A NEW TUBE ASSEMBLY. AIRCRAFT HAS HAD AFFECTED TUBE ASSEMBLY PREVIOUSLY REPLACED BY COMPLIANCE WITH SB 25-336. TUBE ASSEMBLYS IN TAILCONE CAN BE DIFFICULT TO INSPECT UNLESS VIEWED PROPERLY. A THROUGH VISUAL INSPECTION AT SCHEDULED INSPECTIONS AND WHEN THREE-WAY VALVES ARE REMOVED IS RECOMMENDED.