However, video recordings and data telemetry indicated that one of SpaceShipTwo's pilots pulled the unlock lever earlier in Friday's firing sequence, when the craft was traveling at just over the speed of sound, Hart said. The second lever, which activated the system, was not yet pulled — but the wing sections rotated anyway, Hart said.
Activating the system at that point in the flight dramatically increased the plane's drag at the wrong time: during the rocket-powered ascent rather than the free-fall descent. Within seconds, aerodynamic forces tore the plane apart. Co-pilot Michael Alsbury was killed, but pilot Pete Siebold parachuted down to the ground and survived, albeit with serious injuries.