Search teams have retrieved the cockpit voice and flight data recorders from the EgyptAir plane which crashed into the Mediterranean in May, killing all 66 on board.
It is hoped analysis of the black boxes will shed light on why the plane crashed en route from Paris to Alexandria.
At present no militant group has claimed responsibility for bringing down the aircraft.
The voice and data recorders from the EgyptAir plane that crashed into the Mediterranean are "extensively damaged" and will need repairing before they can be analysed, an Egyptian official has said.
The cockpit voice and flight data recorders are vital for piecing together the last moments of the flight which plunged into the sea, killing all 66 on board.
The black boxes can provide key data, including the last conversations inside the cockpit, information about auto-pilot mode or even smoke alarms. They might also give answers as to why the pilot made no distress call before the crash.
The cause of the crash of the Airbus A320 has not been determined and no militant group has claimed responsibility for bringing down the aircraft between Crete and Alexandria on May 19.
Leaked flight data indicated a sensor had detected smoke in a lavatory and a fault in two of the plane's cockpit windows in the final moments of the flight from Paris to Alexandria.
Egypt's civil aviation minister, Sherif Fathi, has said terrorism is a more probable cause than equipment failure or some other catastrophic event.
Work has begun on analysing data from the two black boxes from the fated EgyptAir flight that crashed into the sea in May.
French air accident investigators confirm the signal detected earlier is from a flight recorder.
The head of Egypt's forensics authority said it is 'too early' to know what caused the EgyptAir plane to crash into the Mediterranean sea.