**6. Conclusions**

The CleanSky 2/Astib research program was launched with the objective of building an iron bird for a new regional transport platform acting as a demonstrator for new technologies such as fully electrical flight-control systems and the definition of a PHM system. This paper detailed the activities performed to support the definition of such a PHM system, starting from a high-fidelity representation of the involved subsystems, then transitioning to a real-time representation to support both the implementation of such models within the iron bird and the rapid generation of a simulated dataset to study the behavior of the case study in both nominal and degraded health conditions. A PHM framework is proposed based on a simple data-driven routine to perform fault detection, an SVM for fault classification, and a particle-filtering routine with auto-tuning, and timevariant degradation models. Such a system was then stressed with several simulated degradation patterns to test the algorithm's readiness to be deployed on the iron bird and its expected performances. Results are encouraging, as the algorithm is suitable for installation on board the technological demonstrator and its expected performances are coherent with the target of the research project. Future work will include the verification of the algorithm behavior in response to flight cycles simulated on the iron bird, which will allow stressing the PHM framework with a widely varying set of maneuvers and include in the analysis the effect of pilot-induced compensations on the fault evolution in time. Outside the scope of the research project, but of significant interest for further research, is the study of the effect of different concurring degradations and their effect on the PHM routines.

**Author Contributions:** Conceptualization, A.C.B., A.D.M., G.J. and M.S.; methodology, A.C.B., A.D.M., G.J. and M.S.; software, A.C.B. and A.D.M.; validation, A.C.B. and A.D.M.; formal analysis, A.C.B. and A.D.M.; investigation, A.C.B. and A.D.M.; resources, A.C.B. and A.D.M.; data curation, A.C.B. and A.D.M.; writing—original draft preparation, A.C.B. and A.D.M.; writing—review and editing, A.C.B., A.D.M., G.J. and M.S.; visualization, A.C.B. and A.D.M.; supervision, G.J. and M.S.; project administration, G.J. and M.S.; funding acquisition, G.J. and M.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** The research work presented in this paper was performed within the ASTIB research project, which has received funding from the Clean Sky 2 Joint Undertaking under the European Union's Horizon 2020 research and innovation program under grant agreement CSJU—GAM REG 2014–2015.

**Data Availability Statement:** Data sharing is not applicable to this article.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
