French investigators are revealing their initial findings on the Algerian plane crash in Mali.
Experts in Paris have been examining the two black box flight recorders retrieved from the wreckage of the plane.
The team has been unable to extract information from one, Remi Jouty, head of France’s BEA air accident investigator, told reporters.
The voice recorder on the 18-year-old aircraft used analogue audio tape, a system replaced in more recent planes by digital technology.
The tape was broken or crumpled in places and had to be repaired, but the pilots’ conversations were still incomprehensible.
“There is sound on the tape but it is unintelligible,” said Jouty.
“The device seemed to be recording but we don’t yet know why it did not work, except that this was not the result of the crash itself, he told a news conference, adding that first indications were that it was a “simple technical problem.”
The strong concentration of debris in one spot on the ground leads experts to believe that the plane crashed upon impact rather than disintegrating in the air, Jouty said.