Definition
A fine, woven layer of copper wire embedded in or bonded to the outer skin of a composite aircraft to provide an electrically conductive path that disperses the energy of a lightning strike across the airframe and safely away from internal structure, fuel, and avionics.
Plain English
A thin sheet of woven copper wire built into the surface of a composite airplane so that if lightning hits, the electricity flows around the outside of the aircraft instead of through the inside.
Context Anchor
Seen in discussions of lightning protection on aircraft made with composite materials, especially on wings, fuselage sections, and other outer surfaces.
Derivation
Copper has long been used in electrical work because it conducts electricity exceptionally well. 'Mesh' comes from Old English 'masc,' meaning a net or interwoven pattern. Together the term describes exactly what it is: a conductive net laid over the aircraft skin.
Why Pilots Care
It prevents structural damage, fire, and system failures when a composite airplane is struck by lightning.
Analogy
Think of copper mesh like a screen door made of conductive metal. If electricity hits one spot, the screen gives it many paths to spread out instead of forcing it through one small point.
Intuition Check
Copper mesh is not mainly there to make the aircraft stronger. Its job in this context is to help carry lightning current safely across the surface.
Example Sentence 1
The composite wing skin includes a copper mesh layer to channel lightning current safely around the fuel tank.
Example Sentence 2
The composite fuselage relies on copper mesh to conduct a lightning strike to the static dischargers.