I've had my Phantom 2 for a few days now, and I've already made good use of this forum.  :-)  

My current issue is that my Phantom seems to drift a lot when it's airborne and both sticks are idle.  If I go up and leave it, it never stays in the same place.  It always drifts slowly in one direction or another.  It doesn't rotate, only drift.  

Also, I've had it happen twice that when I get about 100 yards away, it start to gain altitude for no reason, slowly.  The last time it happend, I had trouble controlling it, then suddenly regained control, then crashed into a tree, lol.  

I'm trying to figure out how much drift is normal, or if there is something I can do to lessen this.  

Oh, I'm flying in zero wind.  

IN GPS MODE 18 in. maybe

Do a compass calibration and an advanced IMU calibration.
Then, before you fly at your flying site, do another compass calibration.
Assuming you lock onto >6 sats, see what happens in GPS with no wind.
If this does not help, get back to us...

T J Gilbert Posted at 2014-10-3 09:41
Do a compass calibration and an advanced IMU calibration.
Then, before you fly at your flying site,  ...

Ok, thanks.  I'm gonna do the advanced IMU calibration.  I thought that might be the next step; thanks for the confirmation.  I'll let you know how it goes. . .

This might help if you haven't done it before

Thanks, everybody!  Doing the advanced IMU calibration seems to have fixed my issue.  Took it out this morning, and it was MUCH better.  

It's nice when things work correctly.