Search for Air France 'black boxes' enters second phase

(CNN) - The search for the data and voice recorders from the Air France plane that crashed more than a month ago off Brazil's coast is entering a second phase, according to France's accident investigation agency.

All 228 people aboard the plane were killed in the June 1 crash.

The flight data recorder and the cockpit voice recorder - commonly known as "black boxes" - stop giving out acoustic broadcasts after 30 days. But investigators decided to continue listening for the "pings" for another 10 days after that.

Now, the two U.S. naval vessels and a French Navy submarine will halt their search for the recorders which investigators hope will shed light on exactly how the plane crashed.

The second phase of the search will involved France's oceanographic ship "Pourquoi Pas?" which carries specialized exploration and intervention vehicles, according to the French air accident investigation agency known as the BEA.

The French vessel will conduct new searches using diving equipment and towed sonar, BEA said.

Finding the recorders is of "capital importance" and "no effort must be spared in achieving this end," Air France has said.

"We want to stress that for the sake of the families, we hope that the search for the black boxes will be successful," an Air France representative told CNN.