 This paper reviews the use of unmanned aircraft systems, UAS, for bridge inspection, focusing on multi-rotor UAS. It discusses various levels of automation and autonomy, as well as the equipment needed to capture data and images. Additionally, it provides a summary of techniques used to create models from images, including 3D reconstruction, infrared thermography, structure from motion, SFM, convolutional neural networks, CNN, and more. Software requirements are also discussed, along with the generation of mathematical models to characterize the multi-rotor and optimize its flight path. Finally, the paper concludes by highlighting the limitations of UAS and potential future challenges. This article was authored by Didier Aldana Rodriguez, Diego Leonardo Avala Granados, and Jorge Armando Villalba Vidalas.