The characterization of a Degraded Visual Environment (DVE) System is often focused on the sensors and system architecture. This paper puts forth the case for developing a standard set of rotary-wing DVE system classes based on what the DVE System can do, rather than how it is implemented. This approach supports development of a standard set of safety criteria, and allowable intended uses for each particular class of DVE System. It also controls the relative cost of the DVE System, as the class drives safety criteria, system architecture, and certification costs. Industry can then develop or envision technical solutions to meet those standards, and users can better understand the performance versus cost tradeoffs of the various classes. The DVE industry currently has little or no definition of such classes and is largely left with an ad hoc approach. This concept borrows from the Instrument Landing System (ILS) categories, where the capability is defined by five categories (CAT I, CAT II, CAT IIIa, CAT IIIb, and CAT IIIc). Operators and pilots are not necessarily aware of the technical solution, such as number of antennas, receivers, or amount of redundancy, instead the categories clearly identify the capabilities of each category of system. This paper develops a set of DVE system classes to provide a context for future development of safety criteria and technical solutions.