I have no wish to prejudge the causes of this accident - only to make a simple comment:
We have, on PPRune, had a number of discussions about the efficacy of cockpit voice recorders. There is a misunderstanding - probably brought about by one State's regulations (which only requires them when more than one pilot is carried) - that the fitting of these devices is related only to the capture of voice and communication.
When watching and listening to the camera soundtrack, you can begin to understand why the cockpit environment noise is required to be captured on one of the available channels, and why it is seen as so important by accident investigators.
Jim