Investigators questioned the former head of the Concorde program for nearly 12 hours in connection with the deadly 2000 crash of the supersonic jet.
Lawyers for Henri Perrier did not indicate whether French authorities had begun legal action against him after questioning that began Monday and stretched into early Tuesday.
Perrier served as chief engineer on the aircraft's first test flight in 1969 and directed the Concorde program in the 1980s and early 1990s.
He is the first of four former executives of Aerospatiale - a French plane maker now part of European Aeronautic Defence & Space Co. - called by investigating judge Christophe Regnard in the case.
The others have been summoned for questioning later this week and on Oct. 18. Three other officials from France's civil aviation agency, DGAC, have also been called as part of his investigation.
An Air France Concorde burst into flames just after takeoff from Charles de Gaulle airport on July 25, 2000, killing 109 people on board - mostly German tourists - and four people on the ground.
Two investigations - one by France's accident office, the other ordered by the prosecutors' office - concluded that a titanium "wear strip" that fell from a Continental Airlines DC-10 onto the runway had caused a Concorde tire to burst, propelling rubber debris that perforated the supersonic plane's fuel tanks.
Continental was placed under investigation - a step short of formal charges - in March for alleged manslaughter and involuntary injury. French prosecutors contended that the carrier violated U.S. Federal Aviation Administration rules by using titanium in a part of the plane that normally called for use of aluminum, which is softer.
However, the judicial inquiry, made public last year, also determined that the jet's fuel tanks lacked sufficient protection from shock. The planes flown commercially by Air France and British Airways - were finally retired in 2003, the AP reports.