What flight characteristics may occur if the CG is far aft of the limit?

What flight characteristics may occur if the CG is far aft of the limit?

• A. Reduced longitudinal stability, overly sensitive pitch control, difficulty maintaining nose-down attitudes, potential for stall/spin
• B. Increased stability, sluggish pitch response, easy nose-down recovery, no stall risk
• C. No change in stability, pitch response unchanged
• D. Improved stall margins with aft CG

Answer: (B)

Placing the center of gravity far toward the tail reduces longitudinal stability. With the CG aft of the aerodynamic center, the restoring moment that would normally pull the nose down after a disturbance is weakened or even reversed. That makes the airplane more responsive to pitch disturbances and harder to dampen, so pitch becomes overly sensitive. Because the aircraft doesn’t naturally settle into a nose-down attitude as readily, maintaining a nose-down flight path becomes more difficult. The reduced stability also affects stall behavior—aft CG can make the airplane more prone to entering an aggravated stall or spin because the handling becomes less forgiving and the aircraft is less effectively damped near high angles of attack.

Placing the center of gravity far toward the tail reduces longitudinal stability. With the CG aft of the aerodynamic center, the restoring moment that would normally pull the nose down after a disturbance is weakened or even reversed. That makes the airplane more responsive to pitch disturbances and harder to dampen, so pitch becomes overly sensitive. Because the aircraft doesn’t naturally settle into a nose-down attitude as readily, maintaining a nose-down flight path becomes more difficult. The reduced stability also affects stall behavior—aft CG can make the airplane more prone to entering an aggravated stall or spin because the handling becomes less forgiving and the aircraft is less effectively damped near high angles of attack.