Aviation buttock line

Buttock-line definition: (aviation, ship-building) A curve indicating the shape of an airfoil or nautical equivalent in a vertical plane parallel to the longitudinal axis of the craft or vessel

The body buttock line is a vertical line is drawn through the center of the fuselage

This line is called 0 (zero) body buttock line

As illustrated in Figure 1-45, it divides the fuselage station in half

A series of body buttock lines is then drawn parallel to the 0 line

They are numbered in the same way as fuselage stations

The wing buttlines are parallel to the airplane buttlines, which run down the length of the aircraft

Wing buttline zero is typically where the wing meets the fuselage

This means that, unlike with other sections like the fuselage, the wing stations and buttlines are not perpendicular if the wing has sweep