g. Parallel Course Offsets.
Offsets may be defined to the left or right
of the original course. Once applied they
remain in effect for the remainder of the
flight plan unless canceled.
(1) Parallel Course Offset Geometry. A
parallel course offset may be applied to the flight
plan for weather or traffic avoidance or when
assigned by ATC. When an offset is applied, all
displays keyed to the active waypoint (e.g., time and
distance to go, TO / FROM flag) become referenced
to the pseudo-waypoint at the intersection of the
course change bisector and the offset course. The
leg switch point and the associated 10-second alert
are computed relative to the pseudo-waypoint.
Crosstrack deviation is computed relative to the
offset course. Figure 3C-51 shows the geometry
associated with waypoint switching when a parallel
offset is applied.
Executing Direct-To a waypoint will cancel a
parallel course offset if one has been
(2) Parallel Offset Initiation, Termination, Or
Change. Parallel course offsets may be applied,
changed, or deleted any time the active waypoint is not
identified as a pattern or an approach waypoint. Refer to
Figure 3C-52 and Table 3C-42 for an illustration of
application and deletion of parallel course offset. If the
waypoint identified as a pattern or an approach waypoint
sequencing is selected while an offset is defined, the
offset is automatically canceled and the aircraft will
capture the original flight plan course. If a pattern or
approach is applied to an active waypoint with an offset
applied, the offset is automatically canceled. Initiation of
the Direct-To function automatically cancels the parallel
offset. Refer to Figure 3C-53.
Figure 3C-51. Parallel Course Offset Geometry