Definition
The total weight carried by an aircraft divided by the length of its wingspan, expressed in pounds per foot. It indicates how much weight each foot of wing must support across the span.
Plain English
How many pounds of aircraft weight each foot of wingspan has to carry. A long wing spreads the load over more feet; a short wing concentrates it.
Context Anchor
Seen in aerodynamics, aircraft design, and wake turbulence discussions.
Derivation
Span refers to the wingtip-to-wingtip distance of the wing. Loading means the weight being carried. Together: the weight carried per unit of span.
Why Pilots Care
Span loading affects how a wing performs, especially in terms of induced drag and gust response. Aircraft with low span loading (long wings relative to weight) tend to be more efficient and glide better, which is why sailplanes have very long, slender wings.
Analogy
Think of two people carrying a heavy log. If the log is long, they can stand far apart and share the load comfortably. If the log is short, they're crammed together carrying the same weight in a smaller space. A long wingspan is like the long log -- the load is spread out.
Intuition Check
Span loading does not mean cargo placed across the wings. It means the aircraft’s supported weight compared with its wingspan.
Example Sentence 1
Sailplanes are designed with very low span loading to reduce induced drag and improve glide performance.
Example Sentence 2
The pilot reviewed the span loading diagram to understand where the wing experiences the highest bending stress.