Definition
The distance between the most forward and the most rearward locations along an aircraft's longitudinal axis where the center of gravity is allowed to fall, as established by the manufacturer. As long as the loaded aircraft's center of gravity sits within this range, the aircraft will remain controllable and stable in flight.
Plain English
It is the front-to-back zone where the aircraft's balance point must sit. Load the aircraft so the balance point falls inside this zone and the aircraft will fly properly. Outside it, the aircraft becomes unsafe to fly.
Context Anchor
Seen in aircraft weight-and-balance data, loading charts, and preflight planning before deciding whether the aircraft is loaded safely.
Derivation
"Range" comes from Old French rang, meaning a row or line, and came to mean the span between two limits. Here it describes the span of allowable balance-point positions from the forward limit to the aft limit.
Why Pilots Care
Keeping the center of gravity inside this range maintains aircraft stability, control response, and prevents dangerous handling characteristics.
Analogy
Think of balancing a ruler on your finger. The ruler is easiest to balance when your finger is under the right zone. An airplane also has a balance zone, but that zone is set by the manufacturer and must be followed.
Intuition Check
Do not think of center of gravity range as the amount of baggage space available. It means the approved forward-to-aft zone where the aircraft’s balance point must fall.
Example Sentence 1
After adding the passengers and baggage, the pilot recalculated the weight and balance to confirm the center of gravity was inside the center of gravity range.
Example Sentence 2
An aft center of gravity outside the published range made pitch control more sensitive than expected.