We have an STEC 60-2 in our Bonanza 36 with a Trimble Approach 2000 GPS and
a King HSI. After we had the autopilot tweaked for tracking a GPS course,
it's been very good tracking in NAV mode.

"Julian Scarfe" wrote in message
news:OKwBc.8$AX2.5@newsfe6-win...

I do the same and I have an STEC 60-2.

The problem seems to be the tracking algorithm. If you're slightly off
track a/p turns the aircraft through, say, 20 degrees, and waits for a CDI
movement. Then it makes largish corrections and ends up snaking its way
along the centerline, albeit with decreasing amplitude oscillations. And
if
*all* you have is a CDI, that's probably the best you can do. But it's
hooked up to the GPS and so I would expect it to be able to turn directly
to
a waypoint without the major heading excursions that scare the hell out of
ATC in a busy environment.

Julian Scarfe