Originally Posted by CONFiture
BEA has been very quiet on those selections ...
Not really. All selections of ATT HDG and AIR DATA have been reported. As to why the selections where done is somewhat in the realm of speculation. I don't think the BEA should engage in PPRuNe style of speculation.
The first selection of AIR DATA and then shortly after ATT HDG to F/O ON 3 makes sense for the AIR DATA part as the PF reports he has no speed indication.
Later both selectors are placed in CAPT ON 3. This may suggest there was a belief that both selectors should be on same source when out of NORMAL.
The last selection is AIR DATA back to NORM.
There is no indication that any of the IR mode selectors where set to ATT at any time.
The various selections of ATT HDG means that all three IRs had been used for attitude display in various combinations. 1 and 2, 1 and 3 and finally 3 and 2. On top of that there was the ISIS.
There is no indication that there was any discrepancy between the four attitude sources.