If an aircraft CG is found to be at 24 percent of MAC, that 24 percent is an expression of the distance from which reference?

• A. Distance from the LEMAC
• B. Distance from the datum
• C. Distance from the leading edge
• D. Distance from the wingtip

Answer: (A)

Expressing CG as a percent of MAC uses the Leading Edge of the Mean Aerodynamic Chord (LEMAC) as the reference point. The percent MAC tells you how far aft the CG is along the mean aerodynamic chord, relative to its length. So a CG at 24 percent of MAC means the distance from the LEMAC to the CG is 0.24 times the MAC length, measured along the MAC toward the trailing edge. This standard reference keeps CG positions consistent across different aircraft configurations. Distances from the wing leading edge or wingtip aren’t used for percent MAC in this context, and the datum is used for moment calculations but isn’t the reference for percent MAC.