Garmin GFC 600 Pilot's Manual page 26

AFCS
ACTIVATING THE FLIGHT DIRECTOR
In an installation that does not support display of command bars,
NOTE:
pressing the FD Key will result in a DISABLD KEY message and all active and
armed mode annunciations will be removed upon autopilot disconnect.
An initial press of the FD key on the GMC 605 or the GA button activates the
Flight Director and adds the command bars to the PFD. If the autopilot is disengaged,
an additional press of the FD key will turn off the Flight Director and remove the
command bars from the PFD.
The FD Key is disabled when the autopilot is engaged.
NOTE:
COMMAND BARS ON GARMIN PFD
Upon activation of the Flight Director, Command Bars are displayed in magenta
on the PFD. If the aircraft is being flown by hand, the Command Bars are displayed
hollow. The Command Bars do not override the Aircraft Symbol. The Command Bars
move together vertically to indicate pitch commands and bank left or right to indicate
roll commands.
18
Hollow Command Bars (Pilot Hand Flying Aircraft, FD Only)
Solid Command Bars (Autopilot Engaged)
Garmin GFC 600 Pilot's Guide
Aircraft Symbol
Command Bars
190-01488-00 Rev. B