Go into programming mode and press MODE again so you are in the advanced screen.

Go to THR-CURVE
Cursor up to NORM and turn the wheel to Idle1, Idle2 and Idle3 and ensure they all say MIX>INH

Exit the throttle curve menu and go down to REVO. MIX and ensure thats INH in all modes if you are using a heading hold radio.

Scroll over to HOV-THR and HOV-PIT and make sure they are set to INH as well.

If you have a 9C Super REVO will already be inhibited but you will need to go into the High/Low pitch menu and set it to MAN and NULL in all modes.