The influence described regarding lift, AOA, tail forces, and stabilizer deflection is primarily attributed to which parameter?

• A. CG position
• B. Wing incidence
• C. Tailplane setting
• D. Air density

Answer: (A)

The position of the center of gravity sets the balance of pitching moments in flight. In steady flight, the weight acting at the CG creates a nose-down or nose-up moment that must be countered by the aerodynamic forces on the tail. If the CG moves forward, the aircraft tends to pitch down, so the tail must generate more downward force (stabilizer deflection increases) to restore balance. That change in tail force also shifts how much lift the wing must provide and alters the trimmed angle of attack the wing needs to maintain level flight. If the CG moves aft, the opposite occurs—the tail may need less downforce or even lift upward, changing the required wing AOA and overall lift. So the CG position primarily controls lift distribution, the angle of attack in trim, tail forces, and stabilizer deflection.

Air density would change the overall lift magnitude but not the trim balance related to CG. Wing incidence is a fixed design parameter and sets the baseline lift curve rather than the current trim situation. Tailplane setting is the result of trimming, not the primary cause of the described effects.