Heading and ground track
Read the heading
Heading is the direction the nose points. Track is the aircraft’s direction over the ground.
Find the selected heading
The selected heading and its bug represent a target. FSS says pressing the heading selector can synchronise the bug to the present heading.
Wind drift
Wind can make ground track different from heading. Compare the displayed heading and track. Check whether a separate drift bug appears in your aircraft.
HSI format
FSS lists Full Compass, ARC and MAP, with Full Compass shown at startup. MAP cannot be used for preview.
Match the mode
HDG guides toward the selected heading; LNAV follows FMS lateral guidance when active; TRACK holds a track reference in its documented context.
The DME readout has its own source. FSS says that when FMS is the primary navigation source, the DME display uses the last selected VOR or localizer source. Check its source and station identifier before using the distance. [130]