1. A method for predicting maintenance operations on a current aircraft engine, comprising: determining, using a processor and a simulation on a set of failure models associated with the current aircraft engine, a failure age corresponding to an age of the current engine at a time of failure, for each failure model of the set of failure models, each said failure model corresponding to a given failure and being represented by a law for the cumulated probability of failure as a function of time expressed in terms of flight cycles; selecting, using the processor, a relevant failure model by selecting one of said failure models of said set of failure models, the relevant failure model having a minimum failure age; determining, using the processor, a relevant first rules module corresponding to the relevant failure model, the relevant first rules module defining a plurality of workscopes as a function of the age of the current aircraft engine expressed in terms of flight cycles; from the plurality of workscopes of the relevant first rules module, selecting, using the processor, a relevant minimum workscope associated with the minimum failure age; and determining, using the processor, a required final maintenance workscope to be done on the current aircraft engine from the relevant minimum workscope and from a required number of flight cycles before a next maintenance operation.