How does a servo trim tab function?

A servo trim tab is designed to assist in moving a primary control surface on an aircraft, such as an aileron, elevator, or rudder. When positioned on a control surface, the trim tab deflects in the opposite direction to the surface, creating a force that reduces the pilot's workload. This allows for fine-tuning of the aircraft's attitude without the need for constant physical input from the control stick or yoke.

For instance, when a pilot wants the aircraft to maintain a particular pitch or yaw without having to hold the control surface in that position continuously, the trim tab adjusts the control surface's effective angle. As a result, it achieves the desired flight attitude with reduced effort. This is particularly useful during long flights where fatigue can become a factor. The additional forces created by the servo trim tab align with the movement of the primary control, thus enhancing control and stability.

The other options do not pertain to the function of a servo trim tab. Adjusting fuel flow is related to engine management, monitoring engine temperature involves instrumentation and sensors, and stabilizing in-flight speed pertains to airflow and pitch management rather than directly involving a trim tab feature.