AF447 accident the FO's control yoke input as well as all available flight conditions were obtainable from existing recording devices.
Cosmo: Did you actually read the report and previous comments....?
... the FO's display screen was
NOT recorded by the FDR. Investigators don't know what was displayed and seen by the F/O which may have spooked him to aggressively pull on his stick and climb 3000 feet into a stall.
A video cam focused on the F/O's instrument panel would have given investigators a clue.