French ships equipped with US listening devices are ending a hunt for the black boxes of an airliner lost over the Atlantic on 1 June.
The BBC reports they have been unable to pick up signals that the boxes were meant to emit for 30 days after the Air France jet crashed with the loss of all 228 lives.
Experts believe the cause of the crash may never be known unless the two flight recorders are recovered.
Flight AF447 was flying from Rio de Janeiro to Paris.
French investigators believe the plane, which disappeared in a storm, broke up on contact with water, not in the air.
The plane's speed sensors appear to have been a factor in the crash but not its cause.
French submarines are still searching for the boxes.