In a scarebus, if in doubt of airspeed, call up the FPV. 2.5-4 deg is cruise, 7-8 is green dot, S, or F speed. Above 8 your AOA is too high. Unfortunately use of the FPV as an AOA is not taught by airbus.
It is used everyday by fighter guys with HUDs.
AF447 would never have happened with better trained pilots. Period.
AF447 crew flew into a thunderstorm, which iced up the Pitot static system, then inputed controls that stalled the aircraft. They failed to recognize the stall and crashed 4 minutes later.
There are some bright engineer types on here. The brightest engineer in the world cannot make up for a poorly trained pilot. The poorly trained pilot will eventually figure out how to screw it up. AKA AF447.