Definition
A structural failure in which a member buckles, crushes, or collapses under a load that pushes its ends toward each other, rather than pulling them apart. In aircraft structures, it appears as crumpled metal, kinked tubing, crushed honeycomb, or a buckled spar cap on the loaded side of a bent component.
Plain English
The part broke because it was being squeezed or pushed in from both ends until it gave way.
Context Anchor
Seen in airframe maintenance inspections, especially when checking wings, fuselage structure, or landing gear areas after damage, overload, or a hard landing.
Derivation
From Latin 'comprimere', meaning 'to press together'. The word names exactly what causes the failure: the part is pressed together until it can no longer hold its shape.
Why Pilots Care
When a structure bends, one side stretches (tension) and the other side gets squeezed (compression). The compression side often fails first by buckling. Recognizing compression damage during inspection helps determine whether a part can be repaired or must be replaced.
Analogy
Push down on the ends of an empty soda can and it suddenly crumples in the middle. That sudden crumple is a compression failure.
Intuition Check
Compression failure does not mean low engine cylinder compression here. In an airframe context, it means a structural part has failed because it was being squeezed or pushed together.
Example Sentence 1
The technician found a compression failure on the lower spar cap where the wing had been bent upward during the hard landing.
Example Sentence 2
Wrinkling along the fuselage longeron indicated early compression failure in the composite structure.