Bought the bird yesterday for my windows10, p3dv3.4 rig.  She hand flies beautifully, but , I am having an issue with the command autopilot  which continually disengages every4/5 seconds

after deployment at around 800/1,000ft. if I hand fly her for a while , then re-engage the command the issue is resolved, not an issue with the 737ngx or the 777 which I've had since they came 

on the scene,. I tried a solution offered by a recent contributor who also uses CH yoke and pedals, of changing the  USB ports, but without success. Can anyone have any suggestions?

Michael King

i also had this problem with the 747.  For me, I have to make sure the aircraft is trimmed so that the plane holds it course without any additional inputs from the yoke and rudder. Then the autopilot will stay on. Depending on your controls, make sure they are centered. 

It seems that your controls are not centered or there is interference from them. You can disable your controls when A/P is engaged through FMC options. Please check the introduction document page 97 about CTL Input with AP ON

Hi also check that the pitch and roll mode are valid. If either one is not (mode struck through in yellow on the FMA) the autopilot may disengage.

Thanks for your  comments guys. yes,   a trim issue, will read documents 97, obviously the big bird is more sensitive to trim prior to autopilot

deployment, than the 777.

Many thanks