Brazil's O Estado de S. Paulo newspaper, citing unnamed investigators, also said some victims of Air France AF 447 were found with little or no clothing, and had no signs of burns.

That lack of clothing could be significant, Jack Casey, an aviation safety consultant in Washington DC, told AP.

"In an in-air break up like we are supposing here, the clothes are just torn away.''

Casey also said multiple fractures were consistent with a midair breakup of the plane, which was cruising at about 10,500m when it went down.

"Getting ejected into that kind of windstream is like hitting a brick wall - even if they stay in their seats, it is a crushing effect,'' Casey said.

"Most of them were long dead before they hit the water would be my guess.''

'Less fuzzy'

With more than 400 bits of debris recovered from the ocean's surface, the top French investigator into the crash expressed optimism on Wednesday about discovering what brought down the Airbus A330-200 on June 1.

Search teams are considering ending their operations next week [AFP]
But Paul-Louis Arslanian, who runs the French air accident investigation agency BEA, told a news conference outside Paris that the conditions in which recovery efforts are continuing were "one of the worst situations ever known in an accident investigation".

He said French investigators were beginning to form "an image that is progressively less fuzzy".

"We can say there is a little less uncertainty, so there is a little more optimism."

But he cautioned that "it is premature for the time being to say what happened".

Brazil's military said the search was becoming increasingly difficult in bad weather and a tentative date of June 25 has been set for stopping recovery efforts.

Search teams have yet to find the aircraft's flight data and voice recorders, commonly known as black boxes.

The boxes are thought to be deep under water and will send out an electronic tapping sound for just two more weeks.