The article presents theoretical and practical aspects of aircraft reliability and safety of the performance of test flights in the operation process. The selected issues of operation of the means of transport in the aspect of the aircraft reliability, as well as the intensity of damage during the performance of test flights were presented. In short, the rules for operating the aircraft during test flights are described. A brief description of the causes of air crashes during test flights was

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... esented, and the main hazards and risk occurring at the same time were shown. Subsequently, the authors' methodology including a diagram for studying the aircraft features in terms of aerodynamic characteristics and performance and a model of the maintenance system of aircraft to perform the test flights, were demonstrated. The elements of the decision-making model, developed for this purpose, were briefly presented, showing the required and defined decision variables, constraints and an objective criterion function. The algorithm of the method was presented, and the examples of practical application and graphical data presentation in the DOSPIL application were indicated. The article was concluded with a short summary in which the main effects and directions of further work were presented.