Definition
An ice protection system that prevents and removes ice on the leading edges of wings and tail surfaces by exuding a freezing-point-depressant fluid (typically glycol-based) through thousands of tiny laser-drilled holes in titanium panels. The fluid mixes with supercooled water on the surface, lowering its freezing point so it cannot adhere as ice, and the airflow carries the mixture away.
Plain English
A wing anti-icing system that pushes a special fluid out through tiny holes along the leading edge. The fluid stops ice from forming and helps any existing ice slide off.
Context Anchor
Seen in discussions of wing leading edges, ice protection equipment, preflight checks, and flight in cold, wet conditions.
Derivation
Called 'weeping' because the fluid seeps out through the porous panel surface in a way that resembles tears or sweat appearing on skin. The image describes exactly what you would see if you watched the wing during operation.
Why Pilots Care
Ice on the wing leading edge disrupts smooth airflow and reduces lift; the weeping-wing system provides continuous protection that can be used on the ground or in flight without the power demands of heated surfaces.
Analogy
It is like a garden soaker hose, but built into the wing: fluid comes out through many small openings instead of one large spray.
Intuition Check
Do not read “weeping” as a leak or damage. Here it means the wing is intentionally releasing fluid through tiny openings as part of an ice-protection system.
Example Sentence 1
Before entering the icing layer, the pilot armed the weeping wings system and confirmed adequate fluid quantity for the expected exposure time.
Example Sentence 2
Once airborne in light icing, the pilot activated the weeping wings and watched the fluid spread smoothly across the leading edges.