The Swedish Accident Investigation Board (SHK) could not fully determine the cause of the crash until the black box was found some 15 months later. The preliminary report is available in English. SHK's final report – not available in English – concluded that an interaction between the aerodynamic transient from the wake vortex and the design of the control laws of the flight control software had caused the airplane to stall, which made it uncontrollable for a short period of time. When the plane entered the vortex the pilot's pitch command was fully "up", which is interpreted as a request for the maximum angle of attack, so the angle of attack of the plane was at the maximum limit of 20°. As the plane passed through the vortex the new direction of the airstream reduced the effective angle of attack to 5°, but since the stick remained in the same position the software moved the control surfaces (canards and elevons) into a pitch-up position. After the plane exited the vortex, some time was required to move the surfaces back towards the neutral position, and meanwhile the plane rapidly pitched up to an angle of attack of 45° and stalled.