Definition
The point along the airplane's longitudinal axis where its total weight is considered to act, and around which the airplane balances in pitch, roll, and yaw. The CG location shifts with how the airplane is loaded — passengers, fuel, and baggage all affect where it sits — and must remain within the forward and aft limits published for that aircraft.
Plain English
It's the balance point of the airplane. If you could hang the loaded airplane from a single string, the CG is the point where it would hang level. Where this point ends up depends on how you load people, fuel, and bags, and it has to stay within set limits.
Context Anchor
You encounter CG when checking weight and balance before flight, and when learning how loading affects control, stability, and angle of attack.
Derivation
From Latin gravitas, meaning 'weight.' The 'center of gravity' is literally the central point of an object's weight — the spot where all the weight effectively acts.
Why Pilots Care
An out-of-limit center of gravity changes the aircraft's stability and control response, which can make takeoff, flight, or landing unsafe.
Analogy
A ruler balanced on one finger has a balance point. Move weight to one end, and the balance point moves. An airplane’s CG works the same way when passengers, baggage, or fuel change the loading.
Grounding Statement
Moving the center of gravity forward makes the nose heavier; moving it aft makes the tail heavier and reduces stability.
Intuition Check
Do not assume the CG is the geometric center of the airplane. It is the balance point of the airplane’s weight, and it can move when the loading or fuel changes.
Example Sentence 1
Before takeoff, the pilot ran the weight and balance numbers and confirmed the center of gravity was within limits for the planned fuel and passenger load.
Example Sentence 2
An aft center of gravity made the aircraft more sensitive to pitch inputs during the approach.