Garmin G3X Pilot's Manual page 374

AFCS
INTERCEPTING AND FLYING A DME ARC
The AFCS will intercept and track a DME arc that is part of the active flight plan
provided that GPS Navigation Mode is engaged, GPS is the active navigation source
on the CDI, and the DME arc segment is the active flight plan leg. It is important
to note that automatic navigation of DME arcs is based on GPS. Thus, even if the
APR key is pressed and LOC or VOR Approach Mode is armed prior to reaching the
Initial Approach Fix (IAF), Approach Mode will not activate until the arc segment is
completed.
If the pilot decides to intercept the arc at a location other than the published IAF (i.e.
ATC provides vectors to intercept the arc) and subsequently selects Heading Mode or
Roll Mode, the AFCS will not automatically intercept or track the arc unless the pilot
activates the arc leg of the flight plan and arms GPS Navigation Mode. The AFCS will
not intercept and fly a DME arc before reaching an IAF that defines the beginning of
the arc segment. Likewise, if at any point while established on the DME arc the pilot
deselects GPS Navigation Mode, the AFCS will no longer track the arc.
LEVEL MODE (GMC 305 ONLY)
Level Mode is coupled pitch and roll modes and is annunciated as both the vertical
and lateral modes when active. Pressing the LVL Key engages the autopilot in Level
vertical and lateral modes. Level Mode does not track altitude or heading. When the
LVL Key is pressed all armed and active modes are cancelled and the autopilot and
flight director revert to LVL mode for pitch and roll. While in level mode, all other
modes are available by pressing the corresponding button.
352
Garmin G3X Pilot's Guide 190-01115-00 Rev. K