JD-EE
My question relative to rate of Roll, Rate of Pitch, and the autoflight wants a look. Within these limits is allowance for a large amount of "Upset". Not in the sense of Stall, more along the lines of rock and roll cockpit (Cabin).
Two things come to mind. One, is the air mass producing accelerations in the cockpit that would challenge normal ergonomics? Well belted (Tightly, as these two pilots must have adjusted to the turbulence), was the action preventive of normal arm, leg movements? If it was, perhaps there was another concern (bear with me). What is the FP's choice given such local "g" challenges. Obviously aware of the a/p's "drop zones", was he sufficiently confident in the automatics continuing the flying such that he made a decision not to deselect? This is important, and goes to a/p in turbulence or in a cell. Involuntary drop means Alternate Law, retained protections, etc.? Does he weigh this against the possibility of Direct Law? I think once in Direct Law, Normal Law is not available until ground re-indexing. Is the choice as simple as continued autoflight in turbulence v. the possibility of having to hand fly in crap?
Re: 121.5. A pilot would be less inclined to announce a current position perhaps, if he thought continued flight was possible, especially if he was loaded up to the gills with alerts, a busy screen, and maintaining control. Control is Black and White under the conditions, you keep it, or you Ditch, maybe, but someone (many) will be hurt or perish with loss of control. Did he choose continued a/p? Or was the upset sudden, and decided for him? Perhaps I can help ease your concern re: comms. Given the result, and the likely need for heroic measures, a pilot simply isn't thinking about talking, except to his mate. (Meaning F/O).