I had the same thing happen with my Fut 9C. It's a PCM transmitter, but all my receivers are PPM. With an 18 plane memory, every time I add another plane, I have to remember to switch to PPM in the MOD menu. Several times I have scrathced my head while all the servos go wild. No expereince with Airtronics, but sounds like you guys above have the problem solved.