© AP Photo/ECPAD
"The tape was a little bit damaged," Rémi Jouty, the head of France's BEA air safety agency, told journalists.
"The BEA laboratory was able to restore the tape. Unfortunately the recordings are so far unusable."
Flight AH5017, a McDonnell Douglas 83 jet that had taken off on July 24 from Ouagadougou in Burkina Faso bound for Algiers, crashed in the Mali desert after asking to turn back as bad weather struck.
France bore the brunt of the tragedy, with nearly half of the victims. Other passengers came from Burkina Faso, Lebanon, Algeria, Spain, Canada, Germany and Luxembourg.
'Deliberate act' not ruled out
Jouty said some of the plane's recording devices allowed investigators to trace its fast descent through stormy weather, but the probe had not yet excluded other possible causes, including error or deliberate action.
It seemed likely that the plane had broken up on impact instead of in the air, he said.
"When we look at the trajectory, this leads us to believe that the plane did not break up into several pieces while in flight. This does not exclude that damage was caused during the flight," he told the press conference in Le Bourget, near Paris.
"I don't think we can at this point exclude the possibility of a deliberate act but we cannot say more for the moment."
N'Faly Cisse, the head of Mali's civil aviation accident commission, told the press conference that the BEA would hand in a fresh progress report in mid-September.
"There will be no further updates until then," he said.
Comment: Maybe it really was vaporized, as first reported when they said it was struck by lightning?
But can lightning do that?
Well, last month lightning started striking people inside their homes, so apparently lightning these days is capable of previously unheard of things!