Apparatus, systems, and methods for inspecting a structure are provided which use a sensor holder, which is configured to support one or more curved linear inspection sensors and may be constructed from rapid prototyping, such as stereolithography. Integrated curved linear ultrasonic transducer inspection apparatus, systems, and methods provide fast and efficient methods of constructing custom inspection devices and inspecting otherwise difficult-to-inspect curved radius features of structures, such as a corner of a hat stringer.