change over a very short linear length - a classic condition for stress concentration, which results in fatigue cracking at that location. Additionally, the metallurgical analysis found that the shaft was incorrectly heat-treated during manufacture and contained contaminant particles such as non-metallic inclusions, which further reduced the shaft's ability to carry the torsional loads as designed. The improper machining and impurities facilitated an accelerated fatigue fracture of this key engine component via unmitigated formation of micro-cracks through the shaft's core, ultimately leading to its failure. Over time, the defects in ''Mikołaj Koperniks shaft became large enough, and the shaft broke, resulting in the physical separation of the low-pressure turbine from the low-pressure compressor. As a result, the low-pressure turbine explosively disintegrated. Ejected with enormous force, pieces of the turbines damaged two further engines and cut through the hull. This caused the failure of the vertical and horizontal flight controls (rudder and elevator), and a catastrophic failure of numerous systems of the aircraft. The sudden loss of control of the flight control surfaces caused a steep, unrecoverable dive, and resulted in a crash, 26 seconds from the time of the original failure. A press article, released in Poland in 2010 and based on the review of archival documentation kept in IPN claimed that the People's Republic of Poland authorities contributed to the crash by demanding savings from LOT and excessive exploitation of engines. As a result of the economic policy of Edward Gierek in People's Republic of Poland in the second half of the 1970s it began raising prices, which started to drag the country into an economic crisis. In such circumstances, the Ministry of Transport required LOT to reduce costs. One of the first measures to reduce costs was to minimize refueling planes in foreign airports due to higher jet fuel prices. Aircraft were fueled in Poland to the maximum possible take-off weight. As a result, the crew used the full length of the runway. Conversely, they had a relatively small amount of fuel in reserve on the return flight, which sometimes forced them to land in bad weather. Flights with a maximal take off weight increased engine wear, since the engines were under greater load. NK-8-4 engines were not particularly reliable. Warranty service life was only 5,000 hours, and about half of LOT engines failed after 2000–3000 hours. Because of this, Polish pilots often called the Il-62 "flying coffins".