Secondary flight controls consist of various tabs; which combination of tabs forms the common types?

• A. Leading edge devices such as flaps and slats.
• B. High-lift devices and primary controls.
• C. Trim tabs used to reduce control forces.
• D. Balance tabs, anti-servo tabs, servo tabs, and spring tabs.

Answer: (D)

Secondary flight controls use small surfaces called tabs attached to the primary control surfaces to adjust how those surfaces move and how much effort the pilot must exert. The common types of tabs you’ll encounter are balance tabs, anti-servo tabs, servo tabs, and trim tabs (with spring tabs also seen on some airplanes). Each plays a distinct role: balance tabs help lighten the control forces by creating a hinge-moment opposing the pilot’s input; servo tabs move in response to the pilot’s command to deflect the main surface, so the control feels lighter; anti-servo tabs move opposite the pilot input to increase stability and center the control feel; and trim tabs set the resting position of a surface so the pilot doesn’t have to hold the controls. Spring tabs function similarly to assist with centering or trimming and return to neutral. Because the question asks for the set of common tab types, this combination captures the primary variations used to alter feel, control authority, and stability. The other options describe devices that are not tabs (like leading-edge high-lift devices) or only one type of tab, not the full commonly used set.