747 autopilot problem

[ivi96 0]

Hi everyone,

I'm having some issues with my PMDG 747. I asked for help in other forums but I didn't get any answer. I hope someone can help me:

basically after 2/3 hours cruising at FL380  my autopilot gots crazy, the aircraft started to bank to the left of my course and descend of 500/600ft. I tried to disengage it, the CMD button light was out, but I wasn't able to take control of the aicraft anymore, It was like stuck. 

I tried to change heading with the heading selector, but nothing: the aicraft kept banking to the left constantly with 5* bank angle. I thought was something related to the magnetic compass, considering I was flying at high latitudes, but I don't think so....

any ideas? 

[berts 97]

Your reported symptoms have been caused by hardware issues in the past.  Check your hardware configuration settings, because something is probably sending spikes to the AP.

Alternatively, it might also be caused by a memory issue if you are using FSX/FSX-SE.