A method for performing a maintenance function of a system under diagnosis includes a step for hierarchical decomposition of the system under diagnosis into sub-systems based on the model of the system and, for each sub-system, steps for determination of a model of the sub-system starting from the model of the system, and allocation of a diagnostic method depending on the processing and memory resources of said sub-system. The method allocated is a first diagnostic method based on the model of the system or a second diagnostic method based on predefined logical relationships. The method further includes calculation of the logical relationships for the sub-systems implementing the second diagnostic method, and the transfer of the logical relationships to the sub-systems implementing the second method and the transfer of the model to the sub-systems implementing the first method.