While on GPS navigation, my auto pilot will keep the needles centered all the way down to minimums.
However, on VOR/ILS navigation, I had a real bad issue with the needle being all over the place, and the autopilot was unable to fly a coupled approach. After troubleshooting, I found the center pin of the coax from the signal splitter to the NAV radio had broken off and was only making momentary contact with the center conductor. Man! That lead to some wild rides trying to follow that nav signal!!!
As soon as I replaced the BNC connector, the autopilot can follow the VOR/ILS with less than one dot of variation.
Scott "Grumpy" Stewart
RV-7 N957RV (First Flight on Dec 18, 2009)
RV-14 N144P (Empennage complete, wings almost complete, fuselage almost complete)
#866 on the Van's RV-7 hobbs
#6563 on Van's generic hobbs