AF447 ACARS report shows the connexion between ACARS and flight systems. AF ground knew in real time what was happening. Should the right person have been before the screen, they had three minutes to call the crew : "Hey, Guys, you have an UAS, Do Nothing, Oh you are already stalled ! : PUSH ! "
Using both binary and human procedures is the key to better safety (IBM always taught that, Hugo lecture is a confirmation).
