<p>The article concludes a series of studies related to the application of the modal passport approach for the diagnostics of wind turbine blades subjected to risks of cumulative damage and fatigue failure. A system based on a modal passport and an integrated sensor network can provide continuous monitoring, enabling predictive maintenance of wind turbines. The technical and methodological aspects of an experimental study of composite blade models with integrated piezoelectric sensors were considered. The effect of blade temperature on modal parameters and presents the dependence of error estimates on the number of averages was examined. Using an finite element model of the composite blade, the ratio of the scales of hidden global and local damage, as well as the resulting changes in modal parameters, were determined. Based on the results of modeling and experimentation, the sensitivity of modal passport methods, applied with an integrated sensor system, to global and local defects was assessed. Conclusions were drawn regarding the high sensitivity of modal shape parameters to defects, and a vision for future research is presented.</p>