As mentioned yesterday, the FAC computers are being considered as a possible causative element in the QZ8501 accident. Leaked information from those who do not wish to be identified has indicated this area of interest by the investigators.
QZ8501: Probe team vets possible computer glitch, crew response | New Straits Times
"The aircraft remains fully controllable if you lose the two FACs,” an Airbus spokesman said by email.
This may be dissembling however. Suppose the FACs remained engaged in Normal Law and failed to detect a failure of that system. Could the FAC system then activate overspeed protection without an actual overspeed?
This need not be a design issue, it could also be a maintenance issue. In any case, if the DFDR data continues to point to the FACs, they should probably salvage the cockpit and recover those boxes for examination.