Editing Flight control surfaces (section)

===Longitudinal axis===
The longitudinal axis passes through the aircraft from nose to tail. Rotation about this axis is called ''roll''.<ref name=MISB/>  The angular displacement about this axis is called bank.<ref>Clancy, ''L.J. Aerodynamics'', Section 16.6</ref> The pilot changes bank angle by increasing the lift on one wing and decreasing it on the other.  This differential lift causes rotation around the longitudinal axis.  The [[ailerons]] are the primary control of bank, especially on smaller aircraft: larger aircraft often use roll spoilers or [[Spoileron|spoilerons]] on the upper wing surface to reduce lift on one wing to aid rolling. The [[rudder]] also has a secondary effect on bank through moving one wing forward and the other backwards, affecting the lift they produce.