What was found
WHILE EN ROUTE TO YIP FROM IND, THE FLIGHT ENGINEER FOUND THE NR 1 ENGINE FIRE DETECTION CIRCUIT BREAKER HAD TRIPPED. ATTEMPTED ONE RESET, BUT THE CIRCUIT BREAKER WOULD NOT RESET. THERE WAS A BUNRING RUBBER SMELL NOTED IN THE COCKPIT. DECLARED AN EMERGENCY INTO YIP. THE PLANE LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE TRACED THE BURNING SMELL BACK TO THE CIRCUIT BREAKER. THE CIRCUIT BREAKER WAS REPLACED AND A OPERATIONAL TEST OF THE SYSTEM WAS CARRIED OUT OK. THE AIRCRAFT WAS THEN RETURNED TO SERVICE. (M)