Originally Posted by
vilas
What's DBUS and SMF?
SMF - Speed Monitoring Function ,its a function of FAC that enables FAC to analyze 4 different sources (3 ADRs and One DBUS(syntetic speed calculated by FAC using AOA,LOAD FACTOR,weight,GPS alt and current configuration). It compares all of these sources between each other and monitor individually each ADR in order to detect Icing Conditions. It also assigns one of 3 Validity status( RELIABLE , FAULT, UNCERTAIN) to each speed source and shows it on ECAM.