Basically, autopilot failure modes can be summarized as these:
Turns right instead of turning left
Turns left instead of turning right
Goes up instead of going down
Goes down instead of going up
An airplane is ALWAYS turning and going up or down, it's never really
in steady state. These pertubations can be small or large. (like a
steep turn descending spiral or a gentle turn).

john smith wrote in message ...
I am interested in learning from everyone...
a. What autopilot your aircraft is equipped with?
b. What aircraft your autopilot is installed in?
c. What does your autopilot use for heading/altitude/attitude reference?
d. What does your autopilot use for loc/gs reference?
e. If your heading/altitude/attitude reference fails, what functions
does you autopilot still provide?
f. With failed heading/altitude/attitude reference, does the loc/gs
still function?