What was found
AIRCRAFT WAS IN LEVEL FLIGHT ON APPROACH TO DESTINATION AIRPORT WHEN CREW NOTICED FLAPS WOULD NOT RESPOND TO SELECTED INPUTS. IT WAS THEN THAT THEY NOTICED HYDRAULIC PRESSURE FLUCTUATING AND DROPPING OFF. THE CREW DIVERTED TO AN ALTERNATE AIRFIELD, USED EMERGENCY FLAPS, AND EMERGENCY GEAR (BLOW DOWN). A NORMAL LANDING WAS MADE. ON SITE INSPECTION REVEALED THE RT MAIN HYDRAULIC PRESSURE LINE HAD CHAFED ON THE FIREWALL STRUCTURE CAUSING A HOLE IN THE LINE. BETTER ISOLATION AND SECURING OF THE NEW LINE SHOULD PREVENT ANOTHER FAILURE. OPER CONTROL NR BTVR31695.