Performed to manufacturer’s instructions, balancing usually  consists of assuring that the center of gravity of a particular  device is at or forward of the hinge point. Failure to properly  balance a control surface could lead to catastrophic failure.  Figure 1-52  illustrates several aileron configurations with  their hinge points well aft of the leading edge. This is a  common design feature used to prevent flutter.  Ailerons are the primary flight control surfaces that move the  aircraft about the longitudinal axis. In other words, movement  of the ailerons in flight causes the aircraft to roll. Ailerons  are usually located on the outboard trailing edge of each of  the wings. They are built into the wing and are calculated as  part of the wing’s surface area.  Figure 1-53  shows aileron  locations on various wing tip designs. Ailerons are controlled by a side-to-side motion of the control  stick in the cockpit or a rotation of the control yoke. When  the aileron on one wing deflects down, the aileron on the  opposite wing deflects upward. This amplifies the movement  of the aircraft around the longitudinal axis. On the wing on  which the aileron trailing edge moves downward, camber is  increased, and lift is increased. Conversely, on the other wing,  the raised aileron decreases lift.  [Figure 1-54]  The result is  a sensitive response to the control input to roll the aircraft. The pilot’s request for aileron movement and roll are  transmitted from the cockpit to the actual control surface in a  variety of ways depending on the aircraft. A system of control  cables and pulleys, push-pull tubes, hydraulics, electric, or a  combination of these can be employed.  [Figure 1-55] Simple, light aircraft usually do not have hydraulic or electric  fly-by-wire aileron control. These are found on heavy and  high-performance aircraft. Large aircraft and some high- performance aircraft may also have a second set of ailerons  located inboard on the trailing edge of the wings. These  are part of a complex system of primary and secondary  control surfaces used to provide lateral control and stability  in flight. At low speeds, the ailerons may be augmented by  the use of flaps and spoilers. At high speeds, only inboard  aileron deflection is required to roll the aircraft while the  Figure 1-54.  Differential aileron control movement. When one aileron  is moved down, the aileron on the opposite wing is deflected upward.  Figure 1-52.  Aileron hinge locations are very close to but aft of the  center of gravity to prevent flutter. Ailerons Figure 1-55.  Transferring control surface inputs from the cockpit.  Figure 1-53.  Aileron location on various wings. Stop Stop To ailerons Elevator cables Tether stop Note pivots not on center of shaft 1-26 Down aileron Up aileron