Un vol parabolique, c'est quoi ?

Le vol parabolique est donc un moyen de créer une situation de micropesanteur. Il s'agit de petits bonds entre à environ 10'000 m d'altitude, qui permettent de créer l'état d'apesanteur.
Source : Airzerog.comLes vols paraboliques sont effectués à bord d'un avion, en l'occurrence un Airbus A310 pour les vols Air Zero G, qui suit un profil de vol alternant des manœuvres de montées et de descentes espacées de paliers. Ces manœuvres, appelées paraboles, permettent chacune d'obtenir jusqu'à 22 secondes d'apesanteur. Pendant chacune d'elles, les objets et les personnes à bord ne ressentent plus la gravité, et peuvent flotter librement dans la cabine de l'avion".

What is a parabolic flight ?
Source : Airzerog.com. Parabolic flights are carried out on board an aircraft, in this case an Airbus A310 for the Air Zero G flights, which follows a flight profile which alternates between ascent and descent manoeuvres, divided into phases. These manoeuvres, called parabolas, each allow for up to 22 seconds of weightlessness. During each of these periods, the objects and persons on board do not experience gravity any longer, and can float freely in the aircraft cabin.
Before the parabolic manoeuvre, the aircraft flies horizontally, at an altitude of 20 000 ft. The crew prepare for the parabola by steadily increasing speed to about 810 km/h, the maximum authorized for this type of aircraft. 
The pilot then pulls back steadily on the stick, and the aircraft ascends nose-up until it attains an attitude of 47°, at an altitude of about 25 000 ft . During this phase, referred to as the “entry phase”, a powerful sensation of weight, or hypergravity, is incurred, with the passengers weighing 1.8 times their weight on Earth.