With no progress in the search for the Air France plane, which disappeared over the Atlantic, a French nuclear submarine is being sent to help.
Investigators using radar are scouring the area where it is thought the plane plunged into the sea.
They need to recover the two flight recorders to discover just what happened to the Airbus.
But if the data boxes are not emitting identifying signals, trying to locate them in the sunken depths could prove impossible.
With more questions than answers , the French government has said all scenarios are being considered; from technical problems to stormy weather, and even a possible terrorist attack.
So far no wreckage or any of the 228 victims have been found although suspected debris keeps appearing.
In reality the only known fact is that the crash is Air France’s worst disaster in its 75 year history.