What term is used to define a plane that is perpendicular to the Deck Plane?

The correct term for a plane that is perpendicular to the Deck Plane is the "Normal Plane." This terminology is based on the concepts of geometry and physics used extensively in fields like navigation and aeronautics, where understanding spatial relationships is crucial.

A Normal Plane is defined as a planar surface that is at a right angle (90 degrees) to the Deck Plane, which serves as a reference point for analyzing the orientation of objects and movements in three-dimensional space. This relationship is foundational for many calculations and visualizations, particularly when dealing with the positioning and trajectory of aircraft or weapons systems.

In practical terms, when working on systems that involve elevation or altitude adjustments, it's essential to comprehend how a Normal Plane interacts with the Deck Plane, as this will influence maneuverability and stability. The other terms like Vertical Plane, Horizontal Plane, and Reference Plane serve distinct purposes and do not specifically denote the perpendicular relationship required by the question.