Cardiff is demanding over 120 million euros from the French Ligue 1 club in connection with Sala's death, following a series of previous legal setbacks.
Decisions by FIFA, the Court of Arbitration for Sport (CAS), and the Swiss Federal Supreme Court have all gone against the Welsh club in the legal dispute with Nantes since the player's death in January 2019.
The 28-year-old Sala signed with Cardiff after a club-record 17 million euro transfer from Nantes, as the team fought to avoid relegation from the English Premier League. However, the single-engine Piper Malibu aircraft, carrying the Argentine player from France to Wales, crashed into the sea near Guernsey.
Pilot David Ibbotson also perished in the accident. Following the crash, Cardiff questioned whether the transfer from Nantes had been definitively concluded. However, FIFA ruled that the necessary international registration documents had been submitted.
The businessman who organized the flight was found guilty in 2021 of endangering the safety of an aircraft. Aircraft operator David Henderson had tasked Ibbotson with the flight while he was on holiday. Ibbotson, who regularly flew for Henderson, did not hold a commercial pilot's license, was not authorized to fly at night, and his qualification to pilot the Piper Malibu had expired.
Ahead of a hearing at the Nantes commercial court last year, Cardiff stated its intention to hold Nantes responsible for alleged misconduct by football agent Willie McKay, who helped arrange the flight. Cardiff claims McKay acted on behalf of Nantes, a claim the French club denies.
Cardiff was relegated from the Premier League at the end of the 2018/2019 season and currently competes in England's third tier.