What was found
CAN)PILOTS REPORTED FIRE WARNING ACTIVATED & LASTED ABOUT 20 SECONDS THEN DEACT IVATED. NORMAL LANDING WAS CARRIED OUT BUT SYSTEM ACTIVATED AGAIN ON TAXIING & REMAINED ON. MAINTENANCE TROUBLE SHOT THE FAULT TO THE FIREWALL CONNECTION BEHIND THE INERTIAL SEPARATOR & THE UPPER STANBY SIDE OF THE FIREWALL. CONNECTIONS WERE CLEANED & DRIED & REINSTALLED. APPROXIMATELY 2.5 HOURS INTO SERVICE THE FAULT REAPPEARED. AIRCRAFT GROUNDED FOR FURTHER INVESTIGATION. INVESTIGATION REVEALED THAT BOTH ENDS OF THE FIRE WIRE, ON THE INERTIAL SEPARATOR & ONE UPPER STANDBY SIDE FIREWALL WERE LOOSE CAUSING AN INTERMITTENT CIRCUIT. THE FIRE WIRE WAS REPLACED & NO FURTHER FAULTS WERE OCCURRED.