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In order to promote the application and development of civil aviation safety (CAS) in the field of safety and enrich the theoretical system of CAS research, the methodology of CAS was studied. The definition of CAS was reconstructed, its connotation was explained from four aspects, and its research object was clarified. This paper discussed the mechanism of CAS, that is, to maintain system security through the establishment of safety prevention and control system (SPCS), and explained the research content of CAS from theory and technology application. Five principles and applicable methods for CAS research were summarized. In addition, it put forward the general procedure of CAS research, explained the specific content and implementation method or basis of each step. The research results show that the methodology of CAS is a systematic theoretical system with certain guiding significance, combined with the mechanism, research content, research principles and methods, and research procedures of CAS. [ABSTRACT FROM AUTHOR]

Aiming at the operation processes of air traffic control, which analyses unsafe segments existing in the operation of ATC (air traffic control) from more than 60 civil aviation accidents and errors related to controllers, and expresses these unsafe segments from ATC in the form of the event tree, according to the accident case library evaluates severity of various events, and sums up the ATC factors that impact the unsafe segments; then transforms these human factors into Bayesian networks and counts the probability value of human factors through the field survey and statistics, which uses probabilistic safety assessment methods to determine the likelihood of various events; finally, assessment software simple and quickly applied in ATC operation, verified by practical applications, this method improves the efficiency and accuracy of safety assessment, can reach the targeted prevention ATC error, so as to make the right decisions for the operational risk control. [ABSTRACT FROM AUTHOR]

In this paper, a new kind of method is developed to analyse the bit-error rate for a free-space optical communication system, which is based on the three most important parameters of scintillation statistics, i.e. fraction of time of fade and surge, mean frequency of level crossings, and mean duration of fade and surge. By using this method, the relationship between the bit-error rate and scintillation is clearly identified. The tip-tilt error deteriorates the performance of a free-space optical communication system. Fine tracking ability of adaptive optics (through tip-tilt compensation) can overcome this difficulty. The fade and surge statistical parameters with tip-tilt compensation are evaluated for the plane wave model. The bit-error rate as a function of the scintillation statistical parameters (with tip-tilt compensation) is developed. The results show that the bit-error rate is reduced notably through tip-tilt compensation for free-space optical communication. [ABSTRACT FROM AUTHOR]