PARIS: French Foreign Minister Laurent Fabius said Monday the pilots of an Air Algerie plane that crashed in Mali had asked to “turn back” before contact was lost, in a new development in the probe.

“What we know for sure is that the weather was bad that night, that the plane crew had asked to change route then to turn back before all contact was lost,” he told reporters, before France’s transport minister announced that analysis of the black boxes from the jet could take “weeks.”

The two black boxes from the Algerian passenger jet have arrived in France for analysis.

Martine Del Bono, spokeswoman for the French aviation investigation office, said the data and voice recorders of the Air Algerie plane arrived early Monday and are in the hands of experts.

She wasn’t able to say what condition the boxes are in.

The MD-83 went down early Thursday shortly after takeoff from Ougadougou, Burkina Faso, en route to Algiers, Algeria.

French flags were lowered to half-staff on Monday for three days in memory of the dead, 54 of whom were French.

France has taken a leading role in the investigation. French authorities say extreme bad weather was the likely cause, but rule out nothing.