PARIS -- A French submarine with advanced sonar equipment is due to begin searching on Wednesday for the flight recorders of the Air France airliner which crashed into the Atlantic Ocean last week, the French military said.

The nuclear-powered submarine Emeraude was dispatched to the area last week to help recover the "black box" flight recorders, which may contain clues to explain the disaster and which are believed to lie deep on the Atlantic ocean floor.

"The Emeraude will begin its patrol during the morning in an initial search zone of 36 km by 36," Christophe Prazuck, a spokesman for the French military said. He said the search zone would be changed daily.

All 228 people aboard Air France flight AF 447 from Rio de Janeiro to Paris are believed to have died when the Airbus A330 aircraft crashed into the ocean after flying into stormy weather more than a week ago.

Brazilian military search teams have recovered 41 bodies from the sea and moved some of them to the archipelago of Fernando de Noronha off Brazil's northeastern coast, which is being used as a base for the search operations.

Several pieces of wreckage have also been found but a full understanding of the accident will depend on the black box recorders being recovered.

The doomed jet sent 24 automated messages in its final minutes on June 1, detailing a rapid series of systems failures.

Speed sensors that gauge how fast an aircraft is flying have become the focus of the investigation after some of the messages showed they provided inconsistent data to the pilots.?