The Stability Control Augmentation Systems (SCAS) are devices frequently used in rotary-wing aircraft to improve the stability and reliability of flight and hovering under critical operating conditions; such as rescue missions, maneuvering in cramped areas or close to nearly vertical walls, low visibility or in the presence of heavy turbulence. The SCAS system acts via a limited authority actuator on the aircraft's main control linkage, imitating the pilot-induced command into the movement of the helicopter's main flight actuator. The definition of a Prognostic and Health Management (PHM) framework is crucial for these devices, as it would improve safety and reduce the possibility of sudden failures.