What was found
(CAN) AC WAS UNABLE TO LOWER THE RT MAIN LANDING GEAR. THE EMERGENCY EXTENSION PROCEDURE DID NOT INITIALLY RELEASE THE LANDING GEAR UPLOCK. SUBSEQUENT MANIPULATION OF THE SYSTEM RELEASED THE GEAR TO A DOWN AND LOCKED CONDITION AND THE AIRCRAFT MADE A SAFE LANDING. MAINTENANCE INVESTIGATION REVEALED (2) CONDITIONS WHICH CONTRIBUTED TO THIS SITUATION. IT WAS NOTED DURING INSPECTION OF THE SYSTEM THAT THE EMERGENCY EXTENSION CABLE WAS CONTACTING THE BRAKE ASSY IN SUCH A WAY THAT THE CABLE WAS BEING DEFLECTED APPROXIMATELY .2500 INCH AND COULD PREMATURELY PULL THE HOOK OFF THE ROLLER. THE CONCERN IS THAT THE CABLE MAY FRAY AND BREAK PREVENTING MANUAL EXTENSION OF THE GEAR. THIS WAS NOT A FACTOR IN THIS CASE. INV