Unmanned aerial vehicles (UAV), like other complex mechatronics systems, use servomechanisms for the accurate positioning of construction elements. Servomechanisms are stable, reliable and easy to control. However, occasionally they fail and cause issues for the electrical system. In this paper, the authors present a full analysis of the system operations after a specific fault and the consequences of it. The authors propose a test bench and show the experimentation results that contain servo motor electrical parameters at loaded and idle states, the relations to the manufacturer technical specifications, and possible fault detection and elimination solutions. The obtained results could be implemented into existing popular UAV control systems to improve reliability and fault tolerance of commercial products.