Last night I put my FC40 on the computer to check the battery voltage. I seen a video showing how to correct the voltage reading on the phantom. Come to find out it was reading low so I adjusted it. I decided to take her for a spin this evening to see if I got better flight time after the adjustment. Got everything set, ok let's take off....not so fast. When I gave it power it got a few inches off the ground and started oscillating badly then tipped to the ground. I tried it again same thing. Something is fubar here so I'll check the forum for answers. Nothing there so off to YouTube. Got my answer. What I didn't mention that while I was on the computer with her I checked th engines. Not realizing I had switched the motor configure off quad rotor X to quad rotor I. Once I switched it back she flies beautifully. Heart attack averted.