The Federal Aviation Administration (FAA) shares the Environmental Protection Agency's (EPA) concerns about lead emissions from small aircraft. Owners and operators of more than 200,000 piston-engine aircraft operating in the United States rely on aviation gasoline (avgas) to power their aircraft.
Symmetry (noun). a due proportion of the several parts of a body to each other; adaptation of the form or dimensions of the several parts of a thing to each other; the union and conformity of the members of a work to the whole. Symmetry (noun).
generally speaking, a balance or correspondence between various parts of an object; the term symmetry is used both in the arts and in the sciences. In art and design, it is often used in a somewhat loose sense, to mean a kind of balance in which the corresponding parts are not necessarily alike but only similar.1) A symmetry, in the narrow sense, is a reflection with respect to a plane Î± in space or with respect to a line a in the plane. Such a symmetry is a transformation of space or the plane that takes every point M into a point Mâ such that the line segment MMâ is perpendicular to Î± or a and is divided in half by Î± or a.