Incontrol6 and A33ZAB - thanks for confirming/clarifying that point
Although I don't to speculate in AF447's case specifically - wouldn't failure of a FADEC sensed value, from an AD source for example, causing 'reversion' to an alternate/backup mode generate an ECAM and/or ACARS message. (Such as 744 ÉICAS message ENG 1 EEC MODE, for example).