What Is an Aircraft Actuator?

Every phase of flight relies on carefully controlled motion, whether it is a wing flap adjusting for lift or landing gear lowering for touchdown. Behind these movements in most modern aircraft are actuators, which are devices that translate available power into force and movement. In this blog, we will take a look at how actuators are used in aircraft, covering their different forms and the roles they play to emphasize how imperative they are for carrying out various flight tasks.

How Actuators Are Integrated into Aircraft Systems

An aircraft actuator is a device that converts electrical, hydraulic, or pneumatic power into motion, executing commands from a pilot or onboard computers. As simply a means for delivering force, actuators cannot function as isolated components. Instead, they are part of a broader control system that includes sensors, electronics, feedback mechanisms, and a power source. For example, position and load sensors are particularly important for confirming that the output motion of an actuator matches input instructions.

Because actuators serve many roles across an aircraft that are imperative for safe and controlled flight, they are usually implemented with redundancy to prevent any failure from interrupting their operation. Depending on the design, this may come in the form of dual-motor drives, backup hydraulic feeds, or self-contained electrohydrostatic units.

Types of Actuators Used on Aircraft

Actuators are mostly categorized by how they generate and transmit motion, influencing the systems where they are most effective.

Hydraulic Actuators

Hydraulic actuators harness the force of pressurized fluid to run piston assemblies. With exceptional power density and the ability to handle heavy loads, these actuator variants are the preferred choice for landing gear extension and retraction, wheel braking systems, thrust reversers, and primary flight control surfaces. Additionally, they may also be employed for system-specific functions like controlling hydraulic line shutoff valves. However, the weight from the reservoirs, pumps, and plumbing they depend on necessitates careful planning and introduces maintenance challenges like fluid leaks and susceptibility to pressure loss.

Pneumatic Actuators

Pneumatic actuators rely on compressed air to generate mechanical movement, resulting in a system design that is a bit more mechanically simple and lightweight than hydraulic alternatives. Although they cannot provide the same level of force or precision as other actuator types, pneumatic actuators are still well-suited for non-critical auxiliary operations, examples of use including door actuation, latch release mechanisms, and environmental control valves that regulate cabin airflow.

Electromechanical Actuators (EMAs)

EMAs convert electrical energy into mechanical motion through motors, gearing systems, and rotary-to-linear conversion mechanisms like ball or roller screws. Their input is electrical current that is typically supplied from an aircraft’s main power system, contributing to an overall more compact actuation method.

Known for their precision, EMAs are widely applied in trim systems, secondary flight controls, and increasingly in fly-by-wire primary controls. Their maintenance requirements are also less than hydraulic or pneumatic actuator systems, but they must be carefully designed for heat dissipation and redundancy to accommodate electrical overloads or failures.

Electrohydrostatic Actuators (EHAs) and Electrical Backup Hydraulic Actuators (EBHAs)

EHAs and EBHAs represent technologies that merge the strengths of hydraulic and electric actuation. In an EHA, an electric motor drives a self-contained hydraulic pump which, in turn, moves a piston. Because the hydraulic circuit is contained within the actuator assembly, EHAs do not require centralized hydraulic plumbing, reservoirs, or distribution systems, simplifying system architecture.

EBHAs, while similar, are generally used as secondary systems. They function as conventional hydraulic actuators during normal operation but can switch to localized electrical power if the central hydraulic supply fails.

Solenoid Actuators

Solenoid actuators are electromagnetic devices that convert electrical current into mechanical motion. When current flows through a coil in the actuator, it generates a magnetic field that pulls or pushes a movable plunger or armature, producing short-stroke linear displacement. Commonly used for quick on/off control functions, rather than continuous motion, they are applied to operate bleed-air valves, control fuel or hydraulic flow, actuate latches, and engage switches in auxiliary or engine-related systems.

Roller-Screw Linear Actuators

Roller-screw actuators use a roller screw mechanism driven by a motor, a method that distributes loads across multiple contact points for exceptional accuracy and load-handling capacity. Outperforming ball screws in terms of service life and resistance to wear, these actuators are used in high-precision utility applications where long life, high speed, and strong load-bearing capabilities are demanded. They are especially valuable in more-electric aircraft (MEA) architectures, where they take on roles traditionally handled by hydraulic systems in a lighter and more efficient form.

Browse a Vast Selection of Actuators on NSN Supplies

In closing, aircraft actuators translate power into motion across many flight-critical and auxiliary systems alike, driven by different mediums to accommodate specific demands. Regardless of their type or use, guiding seamless actuator performance in aircraft starts with securing quality components. For professionals seeking a trustworthy procurement source, NSN Supplies delivers a wide selection of aviation-grade actuators and other parts from reliable manufacturers.

Our goal is to provide the most convenient purchasing experience, where our customers can always find what they need through our streamlined database and quickly secure highly competitive, timely procurement options. More than that, we aim to provide solutions that are curated to even the most unique requirements. To see how we can serve your operations, feel free to get in touch with our experts by filling out an online RFQ form, giving us a call, or sending us an email.