What is the term for the point about which an aircraft would balance if suspended from the nose and tail?

• A. Datum
• B. Center of Gravity
• C. Moment Arm
• D. Reference Axis

Answer: (B)

Center of gravity is the point at which the aircraft’s weight can be considered to act. If the airplane were suspended from a line, gravity would produce moments from every part of the airframe, and the aircraft would balance only when the total weight’s line of action passes through this single point—the center of gravity. The CG shifts with how weight is distributed (fuel, passengers, baggage) and determines balance and stability in flight. This is different from a datum, which is just a reference point for measurements; a moment arm is the distance from a weight’s line of action to a reference axis used to calculate moments; a reference axis is simply the line used as a basis for those calculations.