One black box recorder from EgyptAir flight MS804, which crashed last month, has finally been found by search teams in a breakthrough for investigators seeking to explain what caused the plane to plunge into the sea, killing all 66 people on board.
The Airbus A320 crashed into the Mediterranean early in the morning on May 19 2016, en route from Paris to Cairo.
Since then, search teams have worked against the clock to locate the wreckage and recover the two black box recorders - crucial for explaining what went wrong - before they stop emitting location signals in approximately one week's time.
The disaster is pushing the aviation industry to develop an alternative solution for black box data retrieval without the need for expensive underwater searches.
Egypt's investigation committee said that a specialist vessel owned by Mauritius-based Deep Ocean Search was forced to salvage the device in stages because it was extensively damaged, although it 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 the recovered device be handed over to Egyptian air accident investigators for analysis.
Two specialist vessels 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.
The black boxes are usually located in the tail, so finding the wreckage and one of the devices narrows the search area considerably.
The investigation committee expects the black boxes to stop emitting signals around June 24 2016, which would make the second device harder to find because the plane crashed in some of the deepest waters of the Mediterranean, about 3,000 metres below the surface.
Radar imagery obtained from the Egyptian military had confirmed previous reports based on Greek and British radar data indicating that the plane swerved sharply to the left, then spun 360 degrees to the right, before disappearing from radar.
That conclusion is important, one aviation source has said, because it goes some way to excluding the possibility that the plane was brought down by a mid-air explosion.
No group has claimed responsibility for bringing down the plane, but investigation sources have said that it was too early to rule out any explanations, including terrorism.
Having found the wreckage, salvage teams will begin a process known as ‘mowing the lawn’ - covering the area in parallel tracks using a deep-sea robot fitted with a camera and grabbing arm.
If intact, the cockpit recorder should reveal pilot conversations and any cockpit alarms, as well as other clues such as engine noise. Crash experts say it may provide only limited insight into what caused the crash, especially if the crew was confused or unable to diagnose any faults.
For that, investigators probably need access to the second black box containing data from the aircraft systems. Finding that will be the main priority, experts said.
Besides the black boxes, key components to be sought include the aircraft's flight computers, which sent out error messages alongside others indicating smoke alarms before the plane crashed.