A French court had earlier this month cleared the two companies of the charge relating to the crash, when a plane from Rio de Janeiro to Paris vanished during an Atlantic storm.

The ruling followed a historic public trial over the crash in pitch darkness of flight AF447 on June 1, 2009.

Families of those who died had sought to establish criminal liability for France’s worst air disaster and the trial focused on whether Airbus had reacted too slowly and whether Air France had done enough to ensure its pilots were sufficiently trained.

Both companies had pleaded not guilty to the charges, for which the maximum corporate fine is €225,000 (US$246,000).

Air France-KLM declined to comment on the prosecutor’s appeal. Airbus was not immediately available for comment.