Picture released on 03 June 2009 by the Brazilian Air Force showing an oil stain in the Atlantic Ocean where Air France flight 447 supposedly crashed on 01 June 2009

The search for flight recorders belonging to the Air France plane that crashed into the Atlantic Ocean last month is nearing an end.

The Brazil-based commander of American forces supporting the search effort, U.S. Air Force Officer Willie Bergs, said that one ship towing a  U.S. Navy listening device had already ended the search.  He said a second ship was expected to depart the area as well.

However, he said a French nuclear submarine will continue to look for the so-called black boxes, containing cockpit voice and flight data recordings.

Ships have been searching since June 15 for the black boxes, which are designed to emit signals for about 30 days.

Without the cockpit voice and flight data records it will be hard, if not impossible, for investigators to piece together the final minutes of the doomed plane and the exact cause of the crash.  

Investigators speculated that problems with the external speed sensors caused incorrect airspeed readings in the cockpit and led to the crash.  

The head of the French investigation, Alain Bouillard, has said the speed sensors were a factor, but not the main cause.

Air France flight 447, traveling from Rio de Janeiro to Paris on June 1, hit a storm and crashed into the ocean, killing all 228 people on board. 

Some information for this report was provided by AFP and AP.