A new operation will begin next year to find the debris of Air France Flight 447, which mysteriously crashed into the southern Atlantic Ocean last year, French officials said.

The search will begin in February and will be the fourth search for debris from the Airbus A330-200, which crashed while flying from Rio de Janeiro to Paris on June 1, 2009. All 228 people on board were killed.

Investigators have not yet established what caused the crash, and large parts of the plane — including both flight recorders — have never been found, despite an extensive search operation that included a French navy submarine.

France’s air accident investigation agency, the BEA, will give details of the searches that will take place in the coming weeks in a meeting with families of the victims, the French Transport Ministry said.

The Air France plane went down in stormy weather, and most of the bodies were never recovered. The plane’s flight data recorder remains missing in the ocean, according to Air France.

Studies of the debris and bodies that were found led the BEA to conclude the plane hit the water belly first, essentially intact. Oxygen masks were not deployed, indicating that the cabin did not depressurize, the BEA revealed in a report last year.

Automated messages sent from the plane in the minutes before the crash showed there were problems measuring air speed, the investigators said, though they said that alone was not enough to cause the disaster.

The area where the plane went down is far out in the Atlantic — two to four days for ships to reach from the nearest ports in Brazil or Senegal in west Africa. The underwater terrain is rough with underwater mountains and valleys, the BEA said.

(Source: CNN)