Aerospace Instrument-Making Annotation << Back Algorithm for Forming a Knowledge Base for Detecting an Aircraft's Pre-Accident Condition Doroshenko А.V., Kulik А.А. An algorithm for forming a knowledge base for identifying an aviation accident during the operation of an unmanned aerial vehicle has been proposed, which allows for obtaining production rules for the knowledge base for assessing the degree of threat of an emergency situation during the flight. The knowledge bases are formed based on the analysis of the influence of combinations of influencing factors on the fl ight safety of an unmanned aerial vehicle. The modeling of an emergency situation has been performed using knowledge bases for assessing the threat of an aviation accident when the technical condition of the aircraft changes. The resulting algorithm can be applied for the development of flight safety systems in terms of determining the degree of threat of an aviation accident and its neutralization during the operation of an aircraft. Keywords: knowledge base formation algorithm, unmanned aerial vehicle, threat assessment, two-factor event combination matrix, and three-factor event combination matrix. DOI: 10.25791/aviakosmos.5.2026.1560 Pp. 55-63.