Altitude, speed, and FPA constraints in the flight plan can be used by the Flight Director (FD) for vertical navigation. These constraints are, depending on the specific instance, manually entered or retrieved from the published altitudes in the navigation database. Manually entered/modified constraints shall be indicated by the cyan pencil icon. A constraint in the flight plan shall be colored amber when the vertical profile is unattainable due to current aircraft performance. If the system is unable to calculate a logical vertical profile due to a constraint conflict or condition, the invalid constraint shall be crossed out.

Advisory constraints in the flight plan (white text) are not factored into the vertical profile and are not used by the FD for vertical navigation.

Constraints shall be colored magenta when supplying guidance for the active FD mode, cyan when armed for upcoming guidance, or white when neither active or armed for navigation. Flight plan navigation and VNAV direct-to is discussed in more detail later in this section. Lateral and vertical FD modes are discussed in the AFCS Section. See the following figure for an example of how different constraints are displayed in the Active Flight Plan.