Question

If an aircraft&#x27;s center of gravity moves aft of the allowable limit, what specific aerodynamic change occurs that makes stall recovery more difficult?

Accepted Answer

When an aircraft&#x27;s center of gravity, which is the point where the total weight of the aircraft acts, moves aft of the allowable limit, the longitudinal stability of the aircraft decreases significantly. Longitudinal stability is the ability of an aircraft to return to its trimmed state after being disturbed in pitch. As the center of gravity shifts rearward, it moves closer to the center of pressure, which is the point where the total lift of the wing acts. This reduction in the distance between these two points decreases the stabilizing moment created by the horizontal stabilizer, which is the small wing at the rear of the aircraft that keeps the nose level. During a stall, the angle of attack, or the angle between the wing chord line and the oncoming air, is dangerously high. To recover from a stall, a pilot must push the control yoke forward to decrease the angle of attack and allow the wing to regain lift. When the center of gravity is too far aft, the aircraft becomes overly sensitive to pitch inputs and lacks the natural nose-down tendency required to break the stall. Because the horizontal stabilizer now has less leverage to counter the pitching moment of the wing, the pilot may find it physically impossible to generate enough downward force at the tail to lower the nose, effectively trapping the aircraft in a stall condition from which it cannot recover.

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If an aircraft's center of gravity moves aft of the allowable limit, what specific aerodynamic change occurs that makes stall recovery more difficult?