Used to fly a 1968 Arrow about 20 years ago with an autopilot. Always used the heading hold feature with the bug on the DG. Coupling to the NAV usually caused some "hunting" or left/right roll.
Now have a 1979 Archer with Piper Autocontrol III B. Just replaced the "modern" LORAN with a sightly newer GX55 thingie. Decided to try coupling the new GPS to the the autopilot. Since I had never used the NAV coupling, I did not realize that the autopilot had to have the heading hold in the "ON" position for anything to couple to it. Wondered why the "new" GPS was letting the plane wander off to the south of the course. My daughter told me it was clearly a short between the headphones. I think she was correct. Hate it when she is right.
Now have a 1979 Archer with Piper Autocontrol III B. Just replaced the "modern" LORAN with a sightly newer GX55 thingie. Decided to try coupling the new GPS to the the autopilot. Since I had never used the NAV coupling, I did not realize that the autopilot had to have the heading hold in the "ON" position for anything to couple to it. Wondered why the "new" GPS was letting the plane wander off to the south of the course. My daughter told me it was clearly a short between the headphones. I think she was correct. Hate it when she is right.
