"Dan Luke" wrote:


Anybody have any ideas?


John Jones, a fellow Cessna Pilots Ass'n member, has put me on the right
track, I believe. The autopilot receives its altitude information via Gray
code from the Garmin transponder. If a particular line is grounded, it would
hold the autopilot at 13,000 ft.

Tomorrow I'll take this information to the avionics shop and see what they
say.

--
Dan
T-182T at BFM