Define center of gravity and why is its position critical to flight safety?

• A. The point where thrust acts.
• B. The point where weight acts; its location affects stability, controllability, and stall characteristics, and must stay within limits.
• C. The location of the pilot's seat.
• D. The point where lift acts.

Answer: (B)

The center of gravity is the balance point of the airplane along the longitudinal axis—the point where weight can be considered to act. Its location matters because it governs how the aircraft responds to pitch, how easy it is to control, and how the wing behaves near stall.

If the CG is forward, the airplane is more stable in pitch and requires more elevator input to raise the nose. This can make rotation on takeoff and pitch changes slower, and it tends to increase the effort needed to maneuver. If the CG is aft, the airplane becomes less stable and more responsive to control inputs, which can make it easier to overstress or overshoot attitudes and can reduce the margin for recoveries at low speeds. The CG also affects stall characteristics by changing how weight is distributed and how effective the elevator is as the wing approaches its critical angle of attack.

Because these effects directly impact flight safety, the manufacturer specifies a CG range, and the airplane must be operated within those limits. Outside the limits, controllability and recoverability can be compromised.

Note: the center of gravity is about where weight acts, not where thrust acts, where lift acts, or where the seat happens to be.