Investigating magistrates believe there were serious lapses in the training of the pilots, the source told AFP.
The leasing company faces a number of charges including manslaughter and negligence or failure to ensure safety.
On July 24th, 2014, the McDonnell Douglas that was leased by Swiftair to Air Algerie crashed in northern Mali with 110 passengers on board, including 54 French citizens, 23 Burkina Faso nationals, and six Spanish crew.
An expert opinion prepared for the investigation found the crash of Flight AH5017 was caused by the pilots' failure to activate a system to prevent icing of the engine probes.
That led the plane to lose speed and plummet downwards in a movement that could not be reversed.
The expert findings, seen by AFP, say the training of the two pilots was “insufficient and incomplete” and they “failed to detect, or realised very late” that the plane was losing speed.
The report also found that the two pilots only flew a few months a year with long gaps between flights, contributing to “a lowering of their level of performance when confronted with unusual situations”.