Gun Effects

Last I checked there is no default key or button binding in FlightGear for a trigger, so you have to define your own. I use the trigger on my joystick, which is the most obvious choice. Just modify your joystick configuration to bind the trigger to the property "/controls/armament/trigger". While you're there I recommend binding the "hat" fore/aft axis to "/controls/flight/elevator-trim", which is how a real aircraft stick works anyway.