The Paris Correctional Court is hearing the case from March 9 to April 2. Swiftair faces charges of involuntary manslaughter over the crash that killed 116 people on July 24, 2014.

The plane was travelling from Ouagadougou, Burkina Faso, to Algiers, Algeria, when it went down in northern Mali. All passengers and crew on board died, including 54 French nationals and 23 people from Burkina Faso.

Investigators say ice likely formed on engine sensors during the flight, sending incorrect readings to the aircraft’s systems. The faulty data triggered a series of technical problems that the crew could not recover from.

French investigators also pointed to possible shortcomings in crew training and procedures at Swiftair, which they say may have contributed to the accident.

Swiftair, however, argues that weather conditions and other external factors played a major role in the crash.

The long-awaited trial follows years of legal delays and is expected to examine whether the airline’s actions contributed to one of the deadliest aviation disasters in the region.