I wonder if this tragedy might convince at least some of the many pilots who fly around in the cruise, sometimes at night or in IMC, in 'TERRAIN' mode that it's really not a good idea? (...and those trainers who teach this practice?)
Mods, I appreciate that you have had a gigantic task deleting posts on this thread that don't pertain to this subject, (as you did my earlier post on this subject), and I appreciate that over the sea, the AF crew would definitely not have been using this mode.
However, more than one person has suggested the possibility that the AF aircraft entered an area of severe turbulence where for whatever reason, the radar returns did not show them how serious the weather immediately ahead of them was.
Pilots who fly along in TERRAIN mode, relying on the other pilot's display for weather radar returns, in my opinion at least, are throwing away an important 'last slice of cheese' in Dr James Reason's model.
Every one of the professional pilots posting on this thread is doing so hoping we can come up with some plan to ensure something like this tragedy can be prevented in the future. My comment about the (I think ill-advised) prolonged use of TERRAIN mode is made with that in mind.