Synopsis On a flight from Launceston, Tasmania, to Melbourne, the B717 aircraft experienced a dual failure of its Flight Management System. The captain reverted to (traditional) VOR navigation. The failure was "consistent with that experienced as a result of primary and secondary flight data conflict. ". A newly installed SW upgrade allowed a reset of the FMSs, but with loss of flight plan information, which required reloading. The aircraft then continued with no further anomalies.
The Occurrence Brief of the incident is available on the ATSB WWW site.