I have trex 450 HDE. I have hitech 65 servos all the way around, with a align RCE-500x gyro with the DX6. I don't use the gain channel as this is for retract later. The other day I was hover, stop to change batery. With new battery in I started to hover and for unknown reason my tail started to kick to the left or right, (almost like someone esle was making it briefly want to turn right or left). I replaced the battery to make sure it wasn't a bad battery and it continue to do the same thing.