It's just under ten months since an Air France flight en route from Rio de Janeiro to Paris plunged into the Atlantic, killing all 228 people on board.             

Investigators have so far been unable to establish the cause of the crash, with an initial search recovering wreckage and bodies, but not the plane's black boxes.       

[Alain Bouillard, Head of Investigations]:             
"This accident in my understanding is a unique accident because of the lack of evidence that allows us to understand it."             

Two ships from the United States and Norway will search for the black boxes off Brazil's northeastern coast at the weekend. 
           
They'll sweep the seabed of a 2,000 square kilometer search zone for at least a month with three underwater drones and two robots. 
           
The head of France's air accident investigation authority, Jean-Paul Troadec, says he hopes the search will bring answers.             

[Jean-Paul Troadec, Director, French Air Accident Investigation Agency]:             
"I would say that in terms of what interests the families and the investigations, if we find the black boxes we believe we will be able to determine the circumstances of this accident and thus be able draw conclusions in terms of security." 

            
The operation, expected to cost around $10 million dollars, is the third effort to find the remains of the aircraft that vanished in one of the world's worst aviation disasters in recent years.