An aircraft is an amazing machine, capable of flying in any direction by rotating about in three dimensions. These are called axes of movement.

The average location of an aircraft's mass is a point that is called the center of gravity. So if you suspend an aircraft from the center of gravity by a line like this, The aircraft remains perfectly balanced. Each of the three axes moves about the center of gravity. The aircraft's principal axes are normal axis, drawn from top to bottom, lateral axis, drawn parallel to the wings, and longitudinal axis, drawn from tail to nose.

Each axis is perpendicular to the other two axes. Let's look at each individually. The rotation about lateral axis is called pitch. This movement changes the vertical direction of the aircraft's nose. The rotation about normal axis is called your, this is the movement of the nose of the aircraft from side to side.

The rotation about the longitudinal axis is called roll. This is the movement of the aircraft's wings. One wing goes up, the opposite wing goes down. So in summary, these are the three principal axes of movement.