Been experimenting with Panther AAMG.
1) When all the way over to the "right" on the rail using 5 control (maximum right), if you shift to 3 control to shoot, when you go back to 5 control the MG has jumped to the other end of the 5 control range (maximum left). (Sounds incoherent, but try it).
2) We may have too may different controls here. You track the sky with your GV view keys and ID a plane (which may be one of many as in a horde over your head). You switch to the controls for the rail and attempt to traverse (which causes you to lose sight of the AC). You then switch to the controls for the 60-degree-arc MG to shoot, until the AC moves out of the arc. In addition to al this, I seem to notice offline that when I switch from the rail control (5) to the MG control (3) my system doesn't initially show the AC; after about half a second it pops back into view. So, SA-wise, this whole procedure is kind of challenging. Too bad we can't just go back to the original method (3 key only) and allow 360 traverse as in the other tanks. I will keep experimenting...