To switch between AVCS and NORMAL mode make sure the gyro and gain channel are in SR mode before doing anything.
Set the SR parameters under the receiver (CH1 + CH3) and in the gyro itself.
Bind GAIN to a switch and you will be able to travel between -100 (AVCS) 0 (NO GAIN and +100 (NORMAL) mode(s).
GYRO INDICATORS:-
Green = NORMAL
Red = AVCS