The Weeping Wing

The Weeping Wing!!

What it is.

        The least common method of de-icing a wing is the weeping wing method, in this method an antifreeze solution is released in addition to de-icing holes through the leading edge of the wing and spreads across the airfoil chemically breaking the bond between the ice and the airframe that has accumulated ice (PHAK Chapter 7). The ice is then sloughed off during aerodynamic flight using the force friction of the moving air.

How it works and how it can break.

The antifreeze solution being leaked out through the wing is due to small holes that are along the leading edge of the wing, though the initial design of the holes is to block ice formation along the edge to begin with by making the ice essentially bridge the gap across the whole and stops the ice from creating a full unified front on the leading edge (PHAK Chapter 7). Which brings us to the main fault in this design, which is the clogging of the holes along the leading edge of the wing that allows the antifreeze to pass out and along the leading edge. The clogging can occur easily in environments where dust and other FOD can blast up and onto the wing, whether that be from low flying in dusty areas where the dirt has settled closer to the surface such as during crop dusting or even just coming off of or onto the runway. As the wing clogging while on the runway isn't very mitigatable, the pilot should still make sure to do a thorough pre-flight check prior to flying with this system, especially in cold weather climates, and if at all possible, they should avoid areas where high dust backwash will block the system.

References:

Pilot's Handbook of Aeronautical Knowledge Chapter 7