The Paris prosecutor has begun an investigation into whether lives were put in danger when an engine explosion forced an Air France Airbus A380 to make an emergency landing in Canada.
Airbus and Air France both said on Thursday they would cooperate with the inquiry that was requested by a group of 11 passengers on board the Paris to Los Angeles flight last September.
"Airbus will provide full technical assistance to the authorities," the European aircraft maker said in an emailed statement.
The complaint was filed against unknown persons, a judicial source said. Nobody was injured in the incident.
France's air accident investigations agency (BEA) has said the engine's main fan and inlet become detached when the engine came apart high over Greenland. Damage was limited to the right outer no. 4 engine and its immediate surroundings.
An Air France spokesman said the airline did not rule out filing its own complaint once the BEA investigation is completed.
The GP7200 engines used on Air France A380s are made by Engine Alliance, co-owned by General Electric and Pratt & Whitney.
Such engine accidents are rare. In 2010, a Qantas A380 made an emergency landing in Singapore after a Rolls-Royce engine exploded shortly after take-off. Investigators blamed a poorly manufactured part.