Method for predicting the wear of a mechanical part, and method for determining the operational risk associated with an aircraft or with a fleet of aircraft

A method for performing a preventive maintenance operation on an mechanical part of an aircraft based on predicted wear of the mechanical part and associated uncertainty for a given usage profile, the usage profile taking account of a plurality of environmental conditions associated with environmental data as well as a usage time of the mechanical part in each of said plurality of environmental conditions, the method comprising:

• a step of determining operational data associated with a plurality of mechanical parts of a same type as the mechanical part under consideration;
• from the operational data determined in the preceding step, a step of determining a plurality of wear prediction models for the part, the mechanical part being divisible into a plurality of elements, each element being modeled using at least one model from the plurality of models;
• for each model of the plurality of models, a step of determining a weighting coefficient as a function of the proximity between the element of the mechanical part and/or the usage profile associated with the operational data used to determine the model under consideration and the element of the mechanical part under consideration and/or the usage profile of the element of the mechanical part under consideration;
• a step of determining wear prediction of the mechanical part under consideration, said prediction being obtained by a weighted average of the predictions made by each of the models of the plurality of models, the prediction performed by each model being weighted by the weighting coefficient associated with said model;
• a step of determining a statistical quantity representative of dispersion of the predictions of the plurality of models, the uncertainty of the prediction being established as a function of this statistical quantity, and
• a step of performing the preventive maintenance operation on the mechanical part using the wear prediction and the uncertainty associated therewith before a failure event related to the mechanical part occurs.