1. A method for prognostics of a structure subject to loads, particularly an aircraft structure, comprising performing on a processor the steps of: providing a first database linking possible loads acting on the structure in operating conditions with a modified state of the structure, including values of a quantity indicative of the state of the structure as modified in the presence of said loads in a predetermined number of relevant points; providing a second database linking changes of the state of the structure induced by pre-established defects in a predetermined number of relevant points of the structure, with possible classes of defects; and, iteratively: detecting the values of said quantity indicative of the state of the structure in a first plurality of primary detection points and in a second plurality of additional detection points; determining from the first database the loads acting on the structure starting from the detected values of the state quantity; estimating, based on the determined loads, the values of the state quantity in the additional detection points; wherein comparing between the estimated values and detected values of the state quantity in the additional detection points; wherein a condition of integrity of the structure is determined if the difference between the detected values and the estimated values of the state quantity in the additional detection points are within a predetermined tolerance, and a condition of defectiveness of the structure is determined if the differences between the detected values and the estimated values of the state quantity are outside a predetermined tolerance.