LOT Polish Airlines Flight 5055 accident's cause was similar to that of LOT Polish Airlines Flight 007's crash seven years earlier. After the disaster of Flight 007, the Polish investigatory commission established that its engine shaft disintegration was the result of metal fatigue; improper alloy preparation resulting in a defective mechanism which was less resistant to fatigue; and a faulty design of the engine shaft. Detection of these faults was possible only after complete disassembly of the engine and detailed analysis of all its elements, and as such was beyond the capabilities of aircraft maintenance personnel. These concerns were addressed by the Polish Government's Special
Polish Operation of the NKVD of the Polish diversionist and espionage groups and POW units"," was approved on August 9, 1937 by the Party's Central Committee Politburo, and was signed by Nikolai Yezhov on August 11, 1937. It was distributed to the local subdivisions of the NKVD simultaneously with Yezhov's thirty-page "secret letter," explaining what the "Polish operation" was all about. The letter from Yezhov was titled, ""On fascist-resurrectionist, spying, diversional, defeationist, and terrorist activity of Polish intelligence in the USSR"". Stalin demanded the NKVD to "keep on digging out and cleaning out this Polish filth." The "Order" adopted the simplified so-called "album procedure" (as