What was found
WHILE THE FLIGHT CREW WAS ATTEMPTING TO UPLOAD THE CURRENT VERSION OF THE NAV DATABASE, THE UPLOAD TERMINATED WITH POWER INTERRUPT DETECTED. MESSAGE ON CDU RED FMS1 MESSAGE ON BOTH HSI AND ADI. THE MAINTENANCE TEAM DETERMINED THE FLIGHT MANAGEMENT COMPUTER WAS AT FAULT. THE COMPLETER WAS REMOVED AND REPLACED WITH AN OVERHAULED UNIT. THE DATABASE WAS UPLOADED AS REQUIRED, OPS CHECKS WERE SATISFACTORY. THE AIRCRAFT WAS RETURNED TO SERVICE