French officials investigating the Air Algerie flight that crashed in Mali killing all 116 passengers on board confirmed on Thursday that the cockpit voice recorder was not usable.
"The tape was a little bit damaged. We were able to extract it... The BEA laboratory was able to restore the tape," said Rémi Jouty, the head of France's Bureau of Investigations and Analyses (BEA) during a press conference. "Unfortunately the recordings are so far unusable."
However, Jouty said that its recording function appeared to be in tact as technicians were able to pick up a sound signal.
"We still don't know the causes of this dysfunction," he said. "It is too early to say if we will be able to obtain some information from this second black box."
Jouty added that the BEA was able to extract information from AH5017 flight's first black box, which provided details such as the plane's speed and altitude.
"We are still working in order to understand the plane's exact trajectory," he added.
He said that all the communications during the flight, which took off on July 24 from Ouagadougou, Burkina Faso bound for Algiers, between the pilots and ground patrol will be examined to understand what happened in the moments before the flight went down.
Jouty said that "deliberate action" could not be ruled out, but that bad weather was the most likely scenario.
An hour after the Mc Donnell MD83 jet left Ouagadougou the pilots asked to turn around as they encountered severe weather conditions.
N'Faly Cisse, the head of Mali's civil aviation accident commission, said that the BEA would submit a fresh progress report in mid-September.
"There will be no further updates until then," he said.
The majority of the victims hailed from France, while other passengers came from Burkina Faso, Lebanon, Algeria, Spain, Canada, Germany and Luxembourg.
French President François Hollande said that the remains of all passengers on the plane - not just the French - would be flown to France.