The FDR is going to French investigators for 'decoding'. Whether that means they don't trust Americans (NTSB) is not clear but the article is mildly amusing as to that point:
France and Canada have been best known for the decoding of flight data and cockpit data recorders. The French are known to have pioneered the introduction of the flight data recorders in air accident investigations.In reality there will probably be NTSB experts in Paris when the boxes get there.
The French now have their hands full--they've yet to find the black boxes for their own Air France 447 crash over the Atlantic and the black boxes found from Yemenia 626 that crashed in the Indian Ocean off the Comoros Islands were 'damaged'. But there was a miracle survivor, a 14 year old girl. Surely they've asked her if she heard or saw anything before impact. If so, they aren't saying.
The voice recorder from Ethiopian 409, when found, will be helpful in putting to rest the allegations that the crew ignored ATC instructions. However, investigators may be able to uncover a cause with the FDR alone, especially if it's mechanical or weather-related. Interestingly, speculation is now including a mechanical possibility after the initial speculation about 'stormy weather' or lightning, etc. The only thing definitively ruled out at this point, from the very first minute the story broke, has been terrorism. That they could determine such a thing so early, without any forensic evidence, can only suggest they have a strong suspicion of the likely cause.