This re-alignment is accomplished using the rudder flight control surface. Each half of the altitude control surface is made of two sections. Trees and other plants help to control surface runoff. The missile then corrects its flight path via the control surface actuators. This can affect the operation of a conventional elevator control surface. There was no evidence of any control surface failure prior to the crash. The controllers measure the position of the flight control surface with sensors such as LVDTs. Control surface flutter is a more likely cause. This allowed the positioning of a rear control surface at the end of each fin. It deflects airflow, generating force on the whole control surface in the desired direction. Each wing has a trailing-edge control surface. The surface enclosing the control volume is referred to as the control surface. The Session 8 system included a control surface with eight faders. A repeated transfer-and-etch process was used to control surface resistivity. A type of aircraft control surface that combines the functions of both flaps and ailerons.