Description: In the article were presented research results of aircraft flight and navigation complex efficiency under disturbed impact by functional stability parameters. Research contains: analysis of the graph structure of flight and navigation complex by the following criteria: the type of topology, the number and location of the nodes, the communication lines, the probability of connectivity, the structural parameters of the graph: the redundancy coefficient of the links, the graph diameter, the coefficient of centralization, aircraft flight and navigation complex functional stability parameters: degree of vertex connectivity (G), degree of edge connectivity (G), the reserve of functional stability. The given research results confirm the low level of functional stability of some elements of aircraft flight and navigation complex, including data transmission system. It was identified that in aircraft flight and navigation complex structure some elements are on the verge of functional stability reserve and have a low degree of vertex connectivity of the structure and a low level of edge connectivity. According to the research results the recommendations for solving the problem of provision of aircraft flight and navigation complex functional stability are suggested. One of the suggestions to eliminate the problem of low aircraft flight and navigation complex functional stability may be further implementation of the structure synthesis by applying methods of the structure optimization by the maximum criterion of the functional stability parameter with a limitation of the system construction cost.
Keywords: flight and navigation complex, destabilizing factors, functional stability