Definition
The separation of bonded layers in a composite structure, where the resin or adhesive holding the layers together has failed, causing the layers to come apart internally even if the outer surface still looks intact.
Plain English
The layers inside a composite part have come unstuck from each other. From the outside it can look fine, but inside it's no longer one solid piece.
Context Anchor
Seen during preflight inspection of outer wing surfaces, tail surfaces, and other aircraft parts made from bonded layers.
Derivation
From Latin 'de-' (apart, away from) and 'lamina' (a thin layer or plate). Composite parts are built from many thin layers bonded together, so 'delamination' literally means the layers coming apart.
Why Pilots Care
Weakens the structural strength of composite parts and can lead to failure if the damage spreads in flight.
Analogy
It is like plywood starting to separate between its sheets. The outside may still look like one piece, but the strength is reduced because the layers are no longer firmly joined.
Intuition Check
Delamination is not just a scratch, dent, or paint problem. The key issue is separation between layers, sometimes partly hidden under the surface.
Example Sentence 1
During preflight, the pilot tapped along the composite wing surface and noted a dull sound in one area, suggesting possible delamination underneath.
Example Sentence 2
Mechanics repaired the tail surface after tap testing confirmed delamination from previous hail damage.