Originally Posted by
RR_NDB
I think you're wrong there.
As an ancient (Concorde...) I'm not too familiar with the data the current AB 'FBW' systems passes on to the FDR, or the exact way this is done.
On Concorde, with an AFCS easily as complex as those of the various ABs we're talking about - even if it was analogue rather than digital - we 'had our fingers' on a lot of signals (both analogue and logic)
inside each of those 'black boxes'. All of those went to the flight test recorders (been there, done that, haven't got the T-shirt, but I still have the G-BSST tie), and
AFAIK all the essential ones went to the FDRs on the production aircraft.
I am entirely open to further clarify to you or (anyone) any point before going deeper into the "probable need for more data" to fully "understand" the behavior of the "complex crew member"
in an investigation of accidents involving "advanced planes"
BTW, Concorde was 'advanced', even if implemented with 1960s technology. And yes, the data we recorded allowed us to fully understand the behavior of the "complex crew member". Like why she 'twitched the rudder' whenever somebody talked on HF... (ancient anecdote).
A discussion about FDRs and FDR data might be interesting, but I think it's totally outside the scope of an internet forum, even one like PPRuNe.
I 'did' FDRs late in my engineering career, so at least I'm familiar with the concepts.