27 TH INTERNATIONAL CONGRESS OF THE AERONAUTICAL SCIENCES Abstract Human error is often cited as a major contributing factor or case of incidents and accidents. Reason proposes a view that many accidents are catalyzed by persons not present at the time of the event. In fact, it is this source of latent conditions that pose a most significant threat to the safety of complex system. Another dimension to human error in aviation are the active errors that can precipitate the alignment or trigger the latent conditions. The risk associated with aviation is a dynamic element that is affected by both latent conditions and significant factors. In our opinion this dynamics nature of risk in aviation can be described in terms of Theory of Catastrophe. Using Reason's latent failure model, we try to describe this dynamics nature using the cusp catastrophe model. In our opinion the descriptive and predictive nature of cusp catastrophe model works as a map to illustrate the nature of aviation accidents in terms of "instability" resulting from the alignment of latent conditions and influence of active errors. 1. Introduction Problems connected with reconstruction of aircraft crashes were the subjects of many works. One can mention here works by Calkins [15], Ditenberger, Haines and Luers [23], Luers and Ditenberger [54], Maryniak [57, 58, 59]. The works mentioned above contained analyses and simulations of specific occurrences. A very interesting work is treatise [15] containing reconstruction of a crash of Boeing 737-300 airliner no. N513AU belonging to USAir airlines (flight 427). The crash took place near Pittsburgh (the aeroplane fell near the town of Aliquippa, Pennsylvania) on September 8 th 1994 [79]. Official statement of the commission of investigating aircraft crashes said that the direct cause of the crash was uncontrolled descents which lead to hitting the ground 1 . Calkins showed that the loss of control over the aircraft could have been caused by a vortex flowing off the wings of a Boeing 747 airliner flying in front of N513AU aeroplane. The effect of this independent expert’s report by Calkins was a range of theoretical works and in-flight investigations (undertaken, among others, by NASA) documenting the existence of threat to the safety of landing approach by such vortex (e.g. work by Nelson and Jumper “Aircraft wake vortices and their affect on following aircraft” [67]). Published data shows that during the ten year period 1997-2006, 59% of fatal aircraft accidents were associated with Loss-of-Control (LOC) [77, 83, 103]. The notion of loss-of- control is not well-defined in terms suitable for 1 Report NTSB [79]. Report stated, that a probable cause of the crash was the loss of control of the aeroplane (claimed in the original) „The National Transportation Safety Board determines that the probable cause of the USAir flight 427 accident was a loss of control of the airplane resulting from the movement of the rudder surface to its blowdown limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide.” AVIATION ACCIDENTS AETIOLOGY FROM CATASTROPHE THEORY POINT OF VIEW Maciej Lasek * , Krzysztof Sibilski **,! , Józef Żurek ** * The State Commission of Aircraft Accidents Investigation, Warsaw, Poland, ** Air Force Institute of Technology, Warsaw, Poland ! Faculty of Power and Mechanical Engineering, Wroclaw University of Technology, Wroclaw Poland Keywords: Theory of Catastrophe, Aircraft Accidents Reconstruction, Aviation Safety, Flight Dynamics Modeling and Simulation