Altitude Hold Mode (Alt) - Garmin G3X Touch Pilot's Manual

AFCS
At 50 feet from the Selected Altitude, the flight director automatically transitions
from Selected Altitude Capture to Altitude Hold Mode and holds the reference altitude.
As Altitude Hold Mode becomes active, the white 'ALTS' annunciation moves to the
active vertical mode field and flashes green for 10 seconds to indicate the automatic
transition.
Setting the selected altitude (Integrated Autopilot Interface):
1) Touch the autopilot, and touch ALT.
2) Touch the Selected Altitude on the PFD, and use the keypad to enter the
desired Selected Altitude.
Setting the selected altitude (GMC 305):
1) Touch the autopilot, and touch ALT.
2) Touch the Selected Altitude on the PFD, and use the keypad to enter the
desired Selected Altitude.
Changing the Selected Altitude while Selected Altitude Capture Mode is
active causes the autopilot to revert to Pitch Hold Mode with Selected Altitude
Capture Mode armed for the new Selected Altitude.

ALTITUDE HOLD MODE (ALT)

Altitude Hold Mode can be activated by touching ALT or ALT Key (GMC
305); the AFCS maintains the current aircraft altitude (to the nearest 10
feet) as the Altitude Reference. The Altitude Reference, shown in the G3X
Touch Autopilot Status Box, is independent of the Selected Altitude, displayed
above the Altimeter. Altitude Hold Mode active is indicated by a green 'ALT'
annunciation in the G3X Touch Autopilot Status Box.
Altitude Hold Mode is automatically armed when in Selected Altitude
Capture Mode. Selected Altitude Capture Mode automatically transitions to
Altitude Hold Mode when within 50 feet of the Selected Altitude. In this case,
the Selected Altitude becomes the Altitude Reference.
264
Automatic transition to ALTS
Mode with ALT Mode armed
Garmin G3X Touch Pilot's Guide 190-01754-00 Rev. E