The G650 solution is a complex oval-shaped fuselage that actually has four distinct radii. The benefit is that the bottom of the fuselage is flattened so less "wetted" area is exposed to the slipstream to create drag, while the floor can be located lower, near the widest point of the fuselage. Such a shape is structurally complex, but the floor carries loads in tension so the weight penalty is minimized. The new fuselage is so strong, in fact, that the G650 will have the lowest maximum cabin altitude of any jet at 4,850 feet, while the airplane is at its certified ceiling of 51,000 feet. At the typical initial cruise altitude of 41,000 feet the cabin altitude will be only 2,765 feet. Gulfstream cabin altitude has always been below the allowable 8,000 feet, but the G650 sets a new standard that will help reduce passenger fatigue during the 12-hour-plus missions the airplane can fly. And, as with other Gulfstreams, 100 percent fresh air is pumped into the cabin with no recirculation.