When climbing after go around, having N1 engaged & HDG armed (green lits), after 1000 AGL my AP(either one) never engage by one push. Needs repeatedly few times. Obviously not right. Any idea why, please?

Sounds like the exact same problem I had with autopilot not engaging any time during flight (although I know this is only on go-arounds) the thing that fixed it for me was trimming properly. Also remember your gear and flaps should be up or coming up when you click the button. You're also going to want to be within 5-10 degrees of your LNAV path theoretically.

 

Hope this helps.

 

Avery Hammerman

Thanks Avery. I think, this time was my joystick(Saitek) issue. After I recalibrate the neutral pos., all is back to normal, at least for now.