In a series of carefully controlled flight tests conducted in World War II by Messerschmitt, it was established that the Me 262 went out of control in a dive at Mach 0.86, and that higher Mach numbers would lead to a nose-down trim that could not be counter-acted by the pilot by use of the control column. The resulting steepening of the dive would lead to even higher speeds and self-destruction of the airframe due to excessive negative G loads. Postwar testing by the British government corroborated Messerschmitt's results, though neither actually exceeded Mach 0.86.