1. A centralized maintenance system for aircraft, the aircraft including line replacement units (LRUs), the LRUs including items of equipment and/or electronic modules of the aircraft and/or physical links, the system comprising: at least one first digital database including data which is information relating to the LRUs; means for updating the data of the database allowing an interface between a centralized maintenance system and means specific to the operator, wherein lifetime information for the LRUs is known and included in the centralized maintenance system, wherein said digital database comprises a mean time between failure (MTBF) data of each LRU, the MTBF data being able to be modified in the database by the updating means, in the course of the life of each LRU, according to at least one event modifying the failure probabilities for at least one LRU.