Echelon formation - Definition and Overview

An echelon formation is one in which each member of a group is positioned behind and to one side of the next, forming a staircase effect. The name of the formation is derived from the French word échelle, meaning ladder.

Militarily, echelon formations were most often used by infantry or cavalry when attempting to flank an enemy army. In modern warfare, the echelon formation is also commonly employed by armored cavalry because it offers both an excellent field of fire and visibility to each tank in the formation.

Echelon formations are also commonly used by civic, or riot police to move crowds either to the left or right.

The name is also applied to the familiar V-shaped formations of flights of geese, ducks and other migratory birds (though this more symmetric formation is properly called a vee formation). Flying in this way aids the birds in covering long distances very efficiently by delaying the shedding of drag-inducing vortices to the birds at each tip of the formation, rather than from each bird individually. Energy efficiency can be raised by as much as 100% in this manner. The formation also facilitates communication and allows the birds to maintain visual contact with each other, and the latter effect is why echelon and vee formations are also commonly adopted by flights of military aircraft engaged on a common mission.