"During field performance testing before the accident, the G650 consistently exceeded target takeoff safety speeds (V2). V2 is the speed that an airplane attains at or before a height above the ground of 35 feet with one engine inoperative. Gulfstream needed to resolve these V2 exceedances because achieving the planned V2 speeds was necessary to maintain the airplane's 6,000-foot takeoff performance guarantee (at standard sea level conditions). If the G650 did not meet this takeoff performance guarantee, then the airplane could only operate on longer runways. However, a key assumption that Gulfstream used to develop takeoff speeds was flawed and resulted in V2 speeds that were too low and takeoff distances that were longer than anticipated.

Rather than determining the root cause for the V2 exceedance problem, Gulfstream attempted to reduce the V2 speeds and the takeoff distances by modifying the piloting technique used to rotate the airplane for takeoff. Further, Gulfstream did not validate the speeds using a simulation or physics-based dynamic analysis before or during field performance testing. If the company had done so, then it could have recognized that the target V2 speeds could not be achieved even with the modified piloting technique. In addition, the difficulties in achieving the target V2 speeds were exacerbated in late March 2011 when the company reduced the target pitch angle for some takeoff tests without an accompanying increase in the takeoff speeds."