within tolerance. Engine No.3 had 8200 hours operating time without repair. The aircraft was allowed to fly to New York with three engines and only the No.4 engine was fully serviceable. The engine shaft's disintegration The Kuznetsov NK-8 is a two-spool turbofan engine with two low pressure turbines driving the fan and low pressure compressor and one high pressure turbine driving the higher stages of the compressor. As the No. 2 engine's low-pressure shaft failed, the low-pressure turbine suddenly separated from the low-pressure compressor, freeing itself. Because the engine combustion chamber was still producing power, the suddenly freed turbine spun out of control with such enormous speed that within a fraction of a second, the centrifugal force caused the turbine to disintegrate. The enclosure of the turbine failed to contain the pieces of the turbine, which were ejected tangentially at high speed, causing severe damage to the tail section of the aircraft. Aftermath The Polish government's Special Disaster Commission sent its findings on the cause of the accident to Moscow. In response, Russian engineers and scientists stated that the reasons given were implausible and that the turbine disintegrated because of engine failure, contrary to what was stated in the Polish report. Many years later it was revealed that after Flight 7's crash, all Il-62s used by Soviet officials and VIPs had their engines discreetly replaced with newer ones. At one occasion, a Polish governmental Il-62M had had specially installed newer engines for a joint Polish-Soviet governmental trip to Beijing; after that, the engines were taken back to the Soviet Union. The Polish commission report also called for some modernizations in the Il-62 design, most notably doubling the flight controls, so that if one system failed the plane would still be controllable. At the time, redundant controls of this kind were in general use in American and European-made airliners. This issue was never addressed by the Soviets; none of their Ilyushins of any type had installed alternate controls. A small statue dedicated to the boxers who perished in the accident – a trigonal prism made of bronze, with a knocked-out boxer statue at the top—is located at the grounds of Warsaw sport club Skra Warszawa. An identical statue is located at the United States Olympic Training Center in Colorado Springs. The statues were funded by Thomas Kane of Printon Kane and Company and AIBA and designed by American sculptor Auldwin Thomas