The prior knowledge of incipient failures of primary flight command electromechanical actuators (EMAs) with prognostic algorithms can be very beneficial. Indeed, an early and proper detection and interpretation of the deterioration pattern can warn for the replacement of the servomechanism before the actual manifestation of the abnormal behavior. Such algorithms often exploit a model-based approach established on the direct comparison between the real (High Fidelity) system and the monitor (Low Fidelity) system to identify fault parameters through optimization processes, with the monitor model allowing to acquire accurate and precise results with a contained computational effort. To this purpose, the thesis aims at presenting a prognostic technique consisting of a simplified monitor model capable of faithfully reproducing the dynamic response of the reference model in terms of position, speed and equivalent current, taking into account the presence of several mechanical and electrical faults: friction, backlash, coil short circuit, static rotor eccentricity, and proportional gain.