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
Airline codes the section below). IATA expanded the 2-letter-system with codes consisting of a letter and a digit (or vice versa) after ICAO had introduced its current 3-letter-system in 1982. Until then only combinations of letters were used. Airline designator codes follow the format xx(a), i.e., two alphanumeric characters (letters or digits) followed by an optional letter. Although the IATA standard provides for three-character airline designators, IATA has not used the optional third character in any assigned code. This is because some legacy computer systems, especially the "central reservations systems", have failed to comply with the standard, notwithstanding the fact that it