Trapped fuel may cause CG shift aft by up to what percent MAC?

• A. 0.5%
• B. 2%
• C. 3%
• D. 1%

Answer: (D)

Understanding how fuel distribution affects where the airplane’s balance sits is key. The center of gravity (CG) can move aft if some fuel remains trapped in a section of the fuel system and cannot be redistributed during flight. This tailward shift is expressed as a percentage of the mean aerodynamic chord (MAC) to provide a consistent, geometry-based measure of how far the CG can move relative to the wing.

For this aircraft, the maximum aft CG shift due to trapped fuel is limited to 1% of MAC. That small allowance is chosen to preserve adequate longitudinal stability and elevator authority under all allowed loading and fuel conditions. So, even in the worst-case trapped-fuel scenario, the CG should not move aft more than that amount.

The other values imply larger shifts or smaller ones than the documented limit and don’t reflect the established operating limitation for trapped fuel on this airplane.