Air France and Airbus must stand trial on involuntary manslaughter charges over the 2009 crash of a Rio de Janeiro to Paris flight that killed all 228 people on board, a Paris court ruled on Wednesday.

Flight AF447 plunged into the Atlantic Ocean during a storm on June 1, 2009, the deadliest crash in Air France's history.

The court followed the general prosecutor's recommendation, overturning an earlier court decision to drop the case against the French flagship carrier and Europe's top aircraft maker.

Lawyers for Airbus immediately said that they would lodge an appeal.

It took two years to find the wreckage of the Airbus A330 jet, which was eventually located by remote-controlled submarines at a depth of 3,900 metres (13,000 feet).

Investigators determined the crash was caused by errors by pilots, who were disorientated by faulty speed monitoring equipment.

The general prosecutor's office call for a manslaughter trial against both Air France and Airbus went beyond the Paris prosecutor's initial demand that only Air France face manslaughter charges.

Both prosecuting teams contested a 2019 decision to drop the charges by the two investigating magistrates assigned to the case, who said they could not ascribe fault to the companies in what appeared to be a case of pilot error.

But prosecutors accuse Air France of indirectly causing the tragedy by providing insufficient training on how to react in case of malfunction of the so-called Pitot tubes, which enable pilots to monitor their speed.

The pilots reacted incorrectly when the plane stalled after the speed sensors froze over.

The Paris appeals court decision was much awaited by victims' families.

"It's a huge satisfaction to feel that we have finally been heard by the courts," Daniele Lamy, president of an association of victims' families, said after Wednesday's ruling.

Since the disaster, pilot training on dealing with unforeseen circumstances has been stepped up in France and several other countries.