Prior to glidepath indications appearing for an approach, the vertical navigation will provide a glidepath preview of the approaching glidepath with a gray diamond. This is displayed while flying the initial or intermediate segment of an approach, before the active waypoint is the FAF waypoint.  The preview is also displayed when the AFCS is coupled to the Vertical Navigation mode (VNAV) while inbound to the FAF waypoint, until the AFCS captures the glidepath (refer to the AFCS Section for more information about Vertical Navigation mode).  The gray preview diamond changes to a solid magenta diamond to indicate the Glidepath Indicator is active.  If the approach type downgrades past the FAF, ‘NO GP’ is displayed in place of the diamond.

The Glidepath Indicator is a vertical deviation scale for GPS approach service levels supporting SBAS vertical guidance or advisory vertical guidance. Full-scale deflection (two dots), is angular with upper and lower limits. The upper limit is ±492 feet (150 meters) and the lower limit depends on the approach service level.