Originally Posted by
RR_NDB
Simultaneous "failure" of critical elements should be reported immediately. The masking (a normal characteristic of a System) of certain faults is not the best approach and can led to delays in implementing proper, precise and in extreme cases, decisive actions.
Absolutely. And the evidence released by the BEA says the time between autopilot disconnect and recognition by the crew ("lost the speeds/alternate law") was 9 seconds.
9 seconds is pretty quick, hard to see how that can be improved. This suggests that specific interface between man/machine was working and the PNF was on the ball.
IMHO the crew, specially PF must be capable to immediately understand what´s going on.
Indeed. One suspects 'probable cause' will be related to the capabilities of the PF. Contributing factors are not yet known but may include other man/machine interfaces. However even if the PNF had realised in 3 seconds (or 23 seconds even) that there were invalid speeds/alternate law it is hard to see from the evidence so far how that would have changed the end result.
( In fact it might be the case that if the aircraft had simply kept quiet, maintained pitch/power/heading, and waited for the (presumed) ice to melt the aircraft would have made it to CDG with maintanance waiting to see what the earlier messages were all about. Perhaps one day UAS will be managed this way)