Editing Flight control surfaces (section)

===Rudder and aileron trim===

Most fixed-wing aircraft have a trimming control surface on the [[elevator (aircraft)|elevator]], but larger aircraft also have a trim control for the rudder, and another for the ailerons. The rudder trim is to counter any asymmetric thrust from the engines. Aileron trim is to counter the effects of the [[centre of gravity]] being displaced from the aircraft centerline. This can be caused by fuel or an item of payload being loaded more on one side of the aircraft compared to the other, such as when one fuel tank has more fuel than the other.