What type of actuator is typically used in an Automatic Pilot Servo?

The correct choice is a double-acting, balanced linear actuator, which is commonly used in an Automatic Pilot Servo. This type of actuator allows for precise control of the control surfaces through bidirectional movement, which is essential for maintaining stability and responding effectively to flight control commands.

In an automatic pilot system, the actuator must respond quickly and accurately to changes in flight conditions, adjusting the control surfaces as required. The double-acting design means that the actuator can extend and retract under pressure from either direction, providing a more balanced and responsive operation. This balances the forces acting on the aircraft and enables fine-tuning of the flight path.

Additionally, the balanced nature of this actuator helps minimize wear and tear, leading to more reliable long-term performance. Such characteristics are vital in an automatic pilot system, where precision and reliability are paramount for safe flight operations.

While pneumatic and electric actuators have their own specific applications, they do not provide the same level of control or responsiveness required for an automatic pilot system as the double-acting, balanced linear actuator does. Single-acting actuators also lack the ability to control movement in both directions effectively, making them less suitable for this application.