This paper is a report of an investigation into tracking and monitoring the integrity of bolted joints using piezoelectric active sensors. The target application of this study is a fitting lug assembly of unmanned aerial vehicles (UAVs), where a composite wing is mounted to a UAV fuselage. The structural health monitoring methods deployed in this study are time-series analysis and high-frequency response functions measured by piezoelectric active sensors. Different types of simulated damage are introduced into the structure, and the capability of each technique is examined. Practical implementation issues, including temperature changes, are also considered in this study. The results collected from the tests show that piezoelectric active sensors and associated signal processing tools can be efficiently used for identifying joint failure modes of a lug assembly.