Data files from crashed EgyptAir flight MS804 were sent to Egypt on Tuesday after one of the plane’s black box flight recorders was repaired in France, bringing investigators closer to explaining the doomed jet’s fate.

The Airbus A320 plunged into the eastern Mediterranean Sea en route from Paris to Cairo on May 19 and all 66 people on board were killed. The cause of the crash remains unknown.

The plane’s Flight Data Recorder was repaired in laboratories belonging to France’s BEA aircraft accident investigation agency late on Monday and the data files transferred to Egypt on Tuesday, Egyptian investigators said.

“The data file was transferred to Cairo today for decoding, validating and studying of data at the laboratories of the central department for aircraft accidents at the Ministry of Civil Aviation,” Egypt’s Aircraft Accident Investigation committee said in a statement.

The process would take several days, the committee said, and repairs on the plane’s second black box, the Cockpit Voice Recorder, started on Tuesday.

Damaged memory chips from the black boxes were flown to France on Monday after Egyptian investigators had tried without success to repair them. The chips should allow investigators to begin transcribing and analysing the recordings and data which may hold key insights into what caused the crash.

The plane is believed to have crashed in the deepest part of the Mediterranean and the black boxes, recovered last week, were badly damaged.

Debris from the jet was brought to Cairo airport on Monday, where investigators will try to reassemble part of the aircraft’s frame in search of additional clues.

The Paris prosecutor’s office opened a manslaughter investigation on Monday but said it was not looking into terrorism as a possible cause of the crash at this stage. – Reuters