Definition
A threaded rod within an electric landing gear actuator that converts the rotary motion of an electric motor into the linear (push-pull) motion needed to extend or retract the landing gear. As the motor turns the screw, a nut riding on the threads travels along its length, moving the gear linkage with it.
Plain English
A long screw inside the landing gear mechanism that turns when the motor runs. As it spins, it pushes or pulls the gear up or down — like a screw jack lifting or lowering the wheels.
Context Anchor
Seen in discussions of retractable landing gear systems, especially electric gear systems and gear extension or retraction problems.
Derivation
Actuator comes from the Latin actus, meaning 'a doing' or 'a driving' — it's the part that does the moving. Paired with screw, it describes a screw that drives motion, rather than one that simply fastens two things together.
Why Pilots Care
If the actuator screw or its motor fails, the gear may not extend or retract normally. Pilots flying aircraft with electric gear should know the emergency extension procedure, which often bypasses the actuator screw entirely using a hand crank or free-fall mechanism.
Analogy
Think of a car jack with a long threaded shaft: turning the handle spins the shaft, and the jack rises or lowers. The actuator screw works the same way, but with an electric motor doing the turning.
Intuition Check
Do not picture an actuator screw as just a small screw that holds parts together. In this context, it is a moving threaded shaft that helps drive the landing gear.
Example Sentence 1
When the pilot selected gear up, the electric motor turned the actuator screw, retracting the main wheels into the wheel wells.
Example Sentence 2
During the gear swing test the mechanic watched the actuator screw extend and retract the nose gear without binding.