Improved methods, systems, and apparatus for inspecting a structure using angle beam shear wave through-transmission ultrasonic signals involves positioning transducers at offset positions on opposing sides of the structure and permits inspection of the inside of the structure beneath surface defects and features. Magnetic coupling can be used for supporting a pair of leader-follower probes and defining offset positions between angle beam shear wave transducers carried by the probes. Inspection data can be collected for supporting real-time generation of three-dimensional image representations of the structure and of internal defects and features of the structure. Image generation and resolution using inspection data from angle beam shear wave ultrasonic signals can be supplemented using pulse-echo ultrasonic inspection data.