Which CG location would you expect to see less stability?

Which CG location would you expect to see less stability?

• A. Aft CG
• B. Forward CG
• C. Neutral CG
• D. Mid-range CG

Answer: (A)

Longitudinal stability is about how the airplane tends to return to its trimmed pitch after a disturbance. The stabilizing effect comes from having the center of gravity ahead of the neutral point; the further forward the CG is (relative to that point), the stronger the restoring moment and the more stable the aircraft. As you move the CG toward the aft end, the restoring moment shrinks. At the aft limit, near the neutral point, the aircraft becomes only marginally stable or unstable and will be more prone to pitching away from its trim after a disturbance. So an aft CG location would have the least stability. A forward CG is more stable, and a mid-range CG is somewhere in between.

Longitudinal stability is about how the airplane tends to return to its trimmed pitch after a disturbance. The stabilizing effect comes from having the center of gravity ahead of the neutral point; the further forward the CG is (relative to that point), the stronger the restoring moment and the more stable the aircraft. As you move the CG toward the aft end, the restoring moment shrinks. At the aft limit, near the neutral point, the aircraft becomes only marginally stable or unstable and will be more prone to pitching away from its trim after a disturbance. So an aft CG location would have the least stability. A forward CG is more stable, and a mid-range CG is somewhere in between.