APPROACH PLOT (continued)
By default, the localiser and glideslope beams are displayed with deviation lines at 1 and 2 dots either side of the beam centreline.
By default, the localiser and glideslope lines flash when the aircraft is within the proximity `box' (4Nm) of the active runway but outside of the glideslope beam.
The plots are erased under the following conditions:
The lateral and vertical deviation graphs display a vertical yellow bar across the plot as an 'incident' marker. This is displayed when any malfunction is activated while these plots are active. The position of the marker is determined by the aircraft position at the time of the incident.
The position of Approach Landing Markers are displayed graphically (as cones) on the vertical deviation graph. The localiser and glideslope beams and the approach marker cones are displayed in red if the associated radio navigation stations are failed.
The position of Microbursts and Windshears are displayed using representative symbols (a shear sign and a spiral with a down arrow) on the lateral and vertical deviation graphs. The symbols are displayed in magenta.
The speed graph plots two parameters: aircraft speed (red) and a reference speed (Vref) (green).