This work is a part of the Automated Rotor Blade Inspection (ARBI) project. ARBI aims to improve the rotorcraft RTB process with novel rotor blade measurement equipment. The objective of this research is to investigate how the variation in structural properties of the rotor blades composite structure affects the dynamical response during the RTB process. It is hypothesized that the variation in stiffness and shift in the center of gravity of the structure is caused by in-service defects and repairs. The results of the NDI inspections give a detailed overview of what type of non-uniformities are found in CH-47 rotor blades. A 2D analytical model is developed to quantify structural blade properties of blades that contain non-uniformities. This model provides the ability to determine the impact of these non-uniformities on the structural parameters based on NDI results and helps to improve the FEM model that is used for RTB simulation.