Definition
A specially reinforced wing rib designed to withstand the inward compressive load exerted by the drag and anti-drag wires that run between the front and rear spars of a wing. Compression ribs are built more robustly than standard ribs because they carry structural loads in addition to defining the airfoil shape.
Plain English
A heavy-duty rib inside a wing that is strong enough to resist being squeezed inward by the tensioned wires running through the wing.
Context Anchor
Seen in aircraft structural descriptions, wing repair work, and inspections of older or fabric-covered wings.
Derivation
Compression comes from the Latin 'comprimere,' meaning to press together. The rib is named for the type of load it resists — being pressed inward from both ends by the bracing wires anchored to it.
Why Pilots Care
These ribs keep the wing from deforming under positive g-loads and help preserve the airfoil shape needed for safe flight.
Analogy
Think of a spacer block between two boards. If something tries to pull or push the boards out of position, the spacer helps keep the distance between them from collapsing.
Intuition Check
Do not think of a compression rib as a part that creates compression. It is a wing rib built to resist compression, meaning it helps stop parts of the wing from being pushed together.
Example Sentence 1
During the wing inspection, the mechanic paid close attention to the compression ribs where the drag wires attached.
Example Sentence 2
Fabric wings depend on properly spaced compression ribs to hold their shape in flight.