The following is an excerpt from Baidu:

Due to the elasticity of the wing, the moment generated by the **Aileron** acting on the wing also causes the wing to twist and deform in the direction opposite to the **Aileron** deflection. This changes the wing's Angle of Attack (AOA), thereby generating a moment under the action of aerodynamic forces that opposes the rolling moment produced by the **Aileron**. When the flight speed reaches a certain value, the rolling moment generated by manipulating the **Aileron** and the moment generated by the elastic deformation caused by the aerodynamic forces on the wing cancel each other out, causing the **Aileron** to fail (i.e., the **Aileron** effect is zero), and the aircraft becomes uncontrollable. This flight speed is called the reversal speed. When the flight speed continues to increase and exceeds the reversal speed, the rolling moment generated by manipulating the **Aileron** will be less than the opposing moment generated by the wing deformation under aerodynamic forces. At this time, the **Aileron** effect is negative and plays an opposite role. ---- This situation is referred to as "**Aileron** Reversal".

Methods to solve the **Aileron** reversal problem include first, increasing the torsional stiffness of the wing box. Another method is to move the **Aileron** closer to the wing root, where the wing stiffness is higher. However, during low-speed flight, due to low aerodynamic efficiency, one must still rely on the outer **Aileron**, where the moment arm is long. Therefore, some aircraft are equipped with inner **Aileron**s and outer **Aileron**s. However, because inner **Aileron**s interrupt the **Flaps**, affecting takeoff and landing performance, aircraft with inner **Aileron**s are not common. Modern transport aircraft, in addition to increasing wing torsional stiffness, more frequently use **Spoiler**s to assist **Aileron**s in roll control at high speeds, sharing part of the load of the outer **Aileron**s.

The following is an attempt to summarize the Aileron configurations of common passenger aircraft models.

A310/A300-600 Series: Only inner Ailerons A320/A330/A340/B737/B757: Only outer Ailerons Early A300/B747/B767/B777/B787/A350: Inner Ailerons and outer Ailerons. During high-speed flight, the outer Ailerons are in the locked position and are only used during low speeds. A380: Composed of three sections: inner, middle, and outer Ailerons.