The recovery of the flight data recorder has raised hopes the mystery of flight AF447 could be solved. [Reuters]

The remains of one of the 228 victims of an Air France flight that crashed into the ocean off Brazil in 2009 has been recovered from the bottom of the Atlantic Ocean.

The body - preserved by high pressure and low temperatures as it lay in crash wreckage, 3,900 metres deep on the seafloor - was still belted to an airline seat as investigators brought it aboard their search vessel off Brazil's northeast coast from a robot submarine, a spokesman for the operation said.

It was the first attempt by the French search party to bring up human remains from the seabed after they recovered the Airbus A330's black box flight data recorders earlier this week.

Investigators hope the recorders could provide clues as to why flight AF447 from Rio de Janeiro went down, killing everyone onboard, in June 2009.

The official cause of the disaster remains unclear, but the crash has been partly blamed on malfunctioning speed sensors used by Airbus.

The European aircraft manufacturer and the airline are currently being investigated for involuntary manslaughter.

The spokesman, based at the France's national police headquarters in Paris, said recovery workers had been working since Wednesday to bring the body to the surface.

"It's difficult because the bodies are well preserved on the seabed with the pressure and the temperature, but bringing them up through warmer water causes decomposition," he said.

The French Interior Ministry said in a statement that investigators on board the search vessel had taken DNA samples from the body. The remains of some of the passengers were found floating in the ocean after the crash.

Relatives for the victims have demanded that all the bodies be recovered from the wreck, but the police statement warned that the deep-water operation faces "highly complex and unprecedented conditions. The technical feasibility of raising the bodies remains highly uncertain".

Source: Agencies