Definition
In aircraft loading, balance is the location of the center of gravity (CG) along the aircraft's longitudinal axis, expressed relative to the forward and aft limits set by the manufacturer. An aircraft is 'in balance' when the CG falls within those approved limits for the aircraft's weight and configuration.
Plain English
Balance is about where the weight sits in the aircraft — front to back. If the combined weight of fuel, passengers, and cargo puts the aircraft's balance point inside the approved range, it will fly and handle as designed.
Context Anchor
Seen during preflight planning when checking passengers, fuel, baggage, and cargo against the aircraft’s weight-and-balance limits.
Derivation
From Latin bilanx, meaning 'having two scale pans' (bi- 'two' + lanx 'plate'). The image is of two pans on a beam that must even out. In aircraft, the pans are replaced by everything ahead of and behind the center of gravity — they must offset each other within limits.
Why Pilots Care
Correct balance keeps the aircraft stable and controllable; incorrect balance can cause excessive control forces, reduced performance, or loss of control.
Analogy
Think of loading a small boat: the total weight matters, but where people sit also matters. If everyone sits too far forward or too far back, the boat may not handle normally.
Intuition Check
Balance does not mean the aircraft simply feels steady in flight. In this context, it means the aircraft is loaded so the center of its weight is within approved limits.
Example Sentence 1
Before departure, the pilot recalculated balance after a passenger moved to the rear seat to confirm the CG was still within limits.
Example Sentence 2
An aft center of gravity reduces longitudinal stability and makes balance harder to maintain in turbulence.