Prior to glideslope indications appearing for an approach, the vertical navigation will provide a glideslope preview of the approaching glideslope 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 gray preview diamond changes to a solid green diamond to indicate the Glideslope Indicator (ILS/LOC) is active.  If the approach type downgrades past the FAF, ‘NO GS’ is displayed in place of the diamond.

The Glideslope Vertical Deviation Indicator (VDI) appears to the left of the Altimeter whenever an ILS frequency is tuned in the active NAV, the frequency is within range, and the aircraft heading and selected course are within 107˚. Like a glideslope needle on a conventional indicator, a green diamond acts as the Glideslope VDI. The green diamond is displayed as the VDI for ground navigation approach frequencies (ILS and LOC), and replaces the conventional glideslope needle indicator. If a localizer frequency is tuned and there is no glideslope signal, “NO GS” is annunciated.