What about a survivable ditching
I find that this incident was treated as a crash much too early. They may have ditched. There may be survivors in life rafts. If they had total electrical failure, they may have ditched hundred of miles from where the electrical failure occurred. The Atlantic Ocean is vast and when they are hundreds of miles from the coast, the rescue planes can only spend a very limited amount of time doing actual searching, having spent a good part of their fuel getting to the search area and needing to keep a large portion to get back to their base. There are very few long range SAR aircraft available. From what I read in the news, France dispatched two aircraft, one Atlantic 2 and one Falcon 50. Thats very few aircraft to be searching the South Atlantic.
What did Brazil send? Their Hercules has long range, but the SAR Embraers 120s and E-99 I saw on the news certainly don't have the range to even reach the mid Atlantic, let alone search it. What did Dakar dispatch, I have no idea.