Plain English Meaning

A system where a small input is boosted by a helper mechanism to produce a larger output. Inside the VSI, this means a tiny pressure difference is used to move the needle through an internal mechanical assist.

Full Definition

Flight control systems in which the pilot's input is amplified or boosted by a mechanical, hydraulic, or electrical device, so that a small force on the controls produces a larger movement of the control surface. In the context of the Vertical Speed Indicator, the term refers to the internal mechanism inside the instrument that uses a calibrated leak and diaphragm to mechanically drive the needle, rather than to cockpit flight controls.

Context Anchor

Seen in instrument and - discussions, especially where use sensed information, such as or , to help control movement.