Weightless Flight (also known as Parabolic Flight) is achieved aboard ZERO-G’s Boeing 727 aircraft named G-FORCE ONE. Weightlessness is achieved by flying G-FORCE ONE through a parabolic flight maneuver. Specially trained pilots fly these maneuvers between approximately 24,000 and 34,000 feet altitude. Each parabola takes 10 miles of airspace to perform and lasts approximately one minute from start to finish.
The maneuver is somewhat like a roller coaster in that the plane is initially pulled up to approximately 45 degrees ‘nose high’. Next the plane is ‘pushed over’ the top to reach the zero-gravity segment of the parabolas. For the next 25 – 30 seconds everything in the plane is weightless. At approximately 30 degrees ‘nose low’ a gentle pull-out is started which allows the Flyers to stabilize on the aircraft floor. Finally, the g-force is increased smoothly to about 1.8 g’s until the aircraft reaches a flight altitude of 24,000 feet. The maneuver is then repeated.
The weightlessness experienced by everyone inside the airplane is actually equivalent to the type of “free fall” you experience when sky diving. In this case however, the body of the aircraft surrounds you and protects you from the on-rushing wind. At the end of the free fall period, the aircraft also scoops you up and carries you back up to the top of the arc to begin the free fall process again.
In addition to achieving zero-g or weightlessness, G-FORCE ONE can also fly a parabola designed to offer Lunar (1/6th) or Martian (1/3rd) gravity. These reduced gravity environments are also created with a modified parabola that is not quite as steep as zero gravity parabola. (via gozerog.com)