Search teams retrieved the cockpit voice recorder from EgyptAir flight MS 804 on Thursday in a breakthrough for investigators seeking to explain what caused the plane to plunge into the eastern Mediterranean last month.
Egypt's investigation committee said in a statement that a specialist vessel owned by Mauritius-based Deep Ocean Search was forced to salvage the device in stages because it was extensively damaged, but was able to retrieve the memory unit.
"The vessel's equipment was able to salvage the part that contains the memory unit, which is considered the most important part of the recording device," the statement said.
Egypt's public prosecutor ordered that the recovered device be handed over to Egyptian air accident investigators for analysis.
Two specialist vessels, John Lethbridge and Laplace, are continuing to search for the second black box, which contains the flight data recorder. They have yet to detect signals from that device but have identified the location of the main parts of the wreckage.
Investigators say the flight recordings held on the black boxes will help to explain why EgyptAir Flight MS804 crashed on May 19, killing all 66 people on board.
The black boxes were estimated to be sitting 10,000 feet below the sea surface, investigators will need to pinpoint the signals from each black box within a few meters and establish whether the pingers are still connected to the recorders.
The investigation committee said Monday the black boxes were expected to stop emitting signals around June 24. That would make the second device harder to find because the plane crashed in some of the deepest waters of the Mediterranean