Due to the nature of Mutke's combat flight, it is impossible to determine the exact speed of his plane, and it is also difficult to estimate the exact speed of sound at that temperature and altitude. Therefore, it is not possible to either prove or disprove his claims, and there is much discussion among experts as to whether the Me 262 was able to reach the speed of sound. It is believed that the damaging effects experienced by Mutke were a side effect of supersonic airstream and shock waves over different parts of the airframe, called buffeting. This effect occurs at speeds approaching Mach 1 but ceases above Mach 1. A number of other Me 262 experienced similar strange accidents, or breaking apart in the sky because of buffeting and the different aerodynamics at the sound barrier. Transonic buffeting effects had also been widely reported by pilots of propeller-driven Allied fighters including the Supermarine Spitfire, P-38 Lightning, P-47 Thunderbolt and P-51 Mustang, aircraft that were known to have top diving speeds of less than 0.85 Mach (although one Spitfire was measured at 0.92 Mach). Allied fighter pilots reported seeing supersonic shock waves and popped rivets during dives as the high-speed air rushing over the wing exceeded Mach 1 even though the forward airspeed of the overall aircraft was well below that speed.