Function and Performance Specification (FPS)

6.2.3.4 3.3 – Required States and Modes

6.2.3.4.1 This paragraph shall identify and define each state and mode of the Materiel System (or relevant subsets of the Materiel System) where each state or mode has requirements distinct from other states or modes. Examples of states and modes include idle, ready, active, post-use analysis, training, degraded, battle-short, emergency, backup, deployed, contingency, and peacetime. The distinction between states and modes is arbitrary. A system may be described in terms of states only, modes only, states within modes, modes within states, or any other scheme that is useful.

6.2.3.4.2 Each state or mode definition shall support the assignment and definition of functions in the FPS. These definitions should be used to identify the states and modes to be supported by the Materiel System or its relevant subsets. A table or other method may be used to show the correlation of states and/or modes to requirements or groups of requirements either directly in this paragraph or in an annex referenced from this paragraph. Alternatively, each requirement may be directly annotated with the applicable state / mode information.

6.2.3.4.3 Only states and modes that support the definition of requirements in the FPS shall be defined. Where no useful states or modes can be defined, this paragraph shall so state, without the need to create artificial distinctions.
6.2.3.4.4 This paragraph shall define the possible transitions between states and modes in terms of the conditions causing the change in state or mode and any actions required to move the Materiel System or relevant subset into the next state. Applicable notation, such as state transition diagrams or similar, should be used to show the relationships between associated states and modes, transitions, and actions.
6.2.3.4.5 This paragraph shall state which states and modes may be concurrent and which are mutually exclusive.
6.2.3.4.6 Requirements relating to different system roles shall also be addressed in this paragraph, where these roles are considered to represent different states or modes.