As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) CLIMBING THROUGH FL300 A LOUD BANG OCCURRED FOLLOWED BY ELECTRICAL SMOKE ORIGINATING FROM THE CENTRE PEDESTAL. PRIMARY NAVIGATION FAILED IMMEDIATELY AS THE GNC-XL FMS FAILED. THE FMS WAS ISOLATED ELECTRICALLY AND THE CREW PERFORMED A RAPID DESCENT AND REQUESTED PRIORITY HANDLING. THE AIRCRAFT LANDED WITHOUT FURTHER INCIDENCE. INVESTIGATION ON THE GROUND REVEALED DAMAGE CONFINED TO THE FMS BOX AND THE UNIT WILL BE SENT TO HONEYWELL FOR FURTHER ANALYSIS.