A tugboat fitted with underwater listening devices joined Thursday the deep-sea hunt for the black box data recorders that could help explain why Air France Flight 447 perished.
The tug will join a French nuclear military submarine already in the zone, 1,100 kilometers (700 miles) off Brazil's coast, hunting for the vital recorders.
If they find a signal, a mini-sub on board a French scientific ship will be deployed to recover the boxes, which hold data that could be key to discovering why the jet did not complete its journey and 228 people lost their lives.
The tugboat has been contracted by France and has been specially kitted out with underwater listening gear on loan from the United States military.
As the hunt for the black box intensified Brazil, meanwhile, said it was determined to bring back to shore as many bodies and pieces of debris as possible from the crash zone.
A flotilla of five Brazilian navy ships and a French frigate have already recovered 41 bodies. They were to be identified on the Brazilian mainland by dental records and DNA tests.
The search and recovery part of the operation headed by Brazil was to continue until at least June 19, air force spokesman Brigadier Ramon Cardoso told reporters in the northeastern city of Recife.
He explained that currents could make the possibility of recovering bodies more difficult after that date but added the period could be extended if conditions permitted and said more bodies may yet be found.
The Air France plane came down June 1 as it was flying from Rio de Janeiro to Paris.
The cause of the disaster was not known, but speculation is focusing on the Airbus A330's airspeed sensors, which may have malfunctioned.
An Airbus spokeswoman in France said the company had written to clients to assure them that its A330 planes were safe, including those with older versions of the sensors, known as "pitot probes".
Airbus and Air France say older pitot probes have been problematic on other Airbus A330s and A340s, and the airline has stepped up a program to install newer devices after pilots' unions threatened to refuse to fly.
The European air safety agency said Tuesday that Airbus models were "safe to operate," but added that a bulletin had gone out to remind airlines of what to do "in the event of loss of, or unreliable, speed indication."
There has been speculation that the A330's speed probes could have iced up during a storm at high altitude and supplied false airspeed data to the cockpit.
This, in turn, could have caused the pilots to fly too slow and stall, or too fast and rip the airframe apart, aviation experts say.
Airbus on Thursday denied a press report that it was considering grounding all long hauls A330 and A340 jets to change the sensors.
French newspaper Le Figaro had reported that the aircraft manufacturer "does not rule out grounding its fleet of 1,000 A330s and A340s to change the (speed) sensors."
The European Aviation Safety Agency (EASA) "has issued a press release that all A330s and other aircraft are safe to operate," an Airbus spokesman said, adding: "We will take legal action against such irresponsible reporting."
The Air France plane was carrying 228 people, passengers and crew, when it crashed as it was flying from Rio de Janeiro to Paris.
The crash is the worst aviation accident since 2001, and unprecedented in Air France's 75-year history.