Definition
Thin sheets of woven or expanded metal wire (typically aluminum or copper) embedded in or bonded to the outer surface of composite aircraft structures to provide a conductive path for lightning current, allowing the strike to flow across the skin and exit without burning through the non-conductive composite material.
Plain English
A thin metal screen built into the outer skin of a composite aircraft so that if lightning hits, the electricity can travel across the surface and leave the aircraft instead of punching a hole through it.
Context Anchor
Seen in discussions of lightning strike protection for aircraft parts made from carbon fiber or other nonmetal materials.
Derivation
A 'mesh' originally meant the open space in a net (Old English 'masc', a net). Here it refers to the woven metal screen pattern. 'Fine' means the wires are thin and the weave is tight, which gives a smooth, even conductive layer without adding much weight.
Why Pilots Care
Ensures composite aircraft withstand lightning strikes without structural damage or fire.
Analogy
Think of a window screen: it is not a solid sheet, but it still forms a continuous net across the opening. Fine metal meshes work in a similar net-like way, but they are used to carry electrical current over an aircraft surface.
Grounding Statement
If lightning hits a protected nonmetal surface, the fine metal mesh helps spread the current over the outside surface rather than allowing one concentrated hot spot to form.
Intuition Check
Do not read “fine” as delicate or unimportant here. It means the metal strands and openings are small and closely spaced, which helps the mesh act like a continuous electrical path.
Example Sentence 1
The composite wing skin contains fine metal meshes that carry lightning current safely around the structure.
Example Sentence 2
Technicians inspected the fine metal meshes for burn marks after the aircraft reported a lightning strike.