The attention in the work is focused on the strength analysis of the vital elements of the aircraft structure. Special attention is focused on defining critical locations from the aspect of possible failures during exploitation. Then, initial damage in the form of initial cracking is assumed in the defined critical zone. The assumed crack sizes are in accordance with the recommendation on allowable damages. For the cracks defined in this way and the corresponding load spectrum, the propagation of the crack until the effective fracture is analyzed. Different crack propagation laws can be used for this purpose. In this paper, the various models were used. The finite element method (FEM) was used for the structural analysis, where special 6-node singular finite elements were used around the crack tip. Since there are always peaks within the real load spectrum, they are modeled using in-house software. This paper deals with research in the domain of estimating the failure of aircraft structures in critical locations under the effect of cyclic loads. The main goal is to provide an efficient computation method. The previous method is illustrated on the analysis of the failure of parts of vital connections of aircraft structures.