I agree with BarracudaHockey, a properly set-up heli will have no problems with FM.

Now if you ever notice any problems with the radio land inmediately. Metal-to-metal contact can have an effect on the FM radio link and show up as a glitch. You will pull your hair out looking for a problem on the radio, when the problem could be a worn bearing, a loose linkage or any loose metal fastener. Just keep that in the back of your head.

Rafael