Definition
Load factor is the ratio of the total aerodynamic load supported by an aircraft's wings to the actual weight of the aircraft. It is expressed as a multiple of gravity, or 'G'. In straight-and-level unaccelerated flight, load factor is 1G, meaning the wings are supporting a load equal to the aircraft's weight. In a level 60-degree banked turn, load factor is 2G, meaning the wings are supporting twice the aircraft's weight.
Plain English
It is how many times its own weight the wings are currently being asked to lift. In level flight the wings lift exactly the aircraft's weight, so the number is 1. In a steep turn or sharp pull-up the wings have to lift much more than that, so the number goes up.
Context Anchor
Seen in stall awareness, steep turns, maneuvering speed, and discussions of how abrupt control inputs or bank angle affect the airplane.
Derivation
Load' refers to the force the wings must carry, and 'factor' means a multiplier. Together it describes how many times the normal load the wings are currently bearing.
Why Pilots Care
Higher load factor raises stall speed, so a pilot can stall at a higher airspeed than expected while maneuvering.
Analogy
An elevator can make you feel briefly heavier when it starts moving upward. The elevator has not changed your body weight, but the force on you has increased. Load factor is the airplane version of that added force.
Grounding Statement
In a steep turn, the wings must hold the airplane up while also turning it, so the airplane carries more force than it does in straight-and-level flight.
Intuition Check
Load factor does not mean how much cargo or passenger weight is on board. Here, it means how many times the airplane’s weight is being imposed by flight forces.
Example Sentence 1
During the steep turn, the pilot felt the increased load factor pressing them into the seat as the wings worked harder to maintain altitude.
Example Sentence 2
The pilot eased out of the dive slowly to avoid raising the load factor enough to cause a secondary stall.