Are you in GPS or NAV mode?
GPS - the CDI would be reading the GPS course
NAV - it would be reading what you had your OBS set to and your NAV receiver set to
the freq of the navaid
what GPS/ NAV do you have, the garmin 430 and the NAV that you can get with it?

I know that when I am having my auto pilot track a VOR it may be off by a dot
sometimes, this is basically because the VOR is not that sensitive when your a ways
from it. But when I shoot a localizer, the AP tracks it perfect. Have you tried
tracking a localizer with your AP ?

Jeff


PaulaJay1 wrote:

I have the original Autocontrol IIIB in my 79 Archer. Lately it has been
flying one dot to the right of course when in GPS/NAV mode. I've set the CDI
scale to 1.0nm full scale on the GPS so the error is only about 0.2 nm. If I
set the heading but to the right a little, we fly right down the line. This
says to me that the autopilot is putting out a small bias to the left that the
GPS/NAV has to constantly correct. Is there a simple adjustment in the
autopilot to correct this? Maybe I should just vent to the newsgroup and leave
good enough alone!

Chuck