True but it is not something that can be selected and tested during powerchecks etc
Not necessarily. IF you have an alternate air lever/knob, it can be selected and tested during power checks. You should note a slight drop in RPM. In the piston engined aircraft I fly it is only noticeable because it's a twin and you can hear the props go out of sync. If you're in a single then the drop may not be noticeable enough to test.
I used to fly an aeroplane with only two wheels, no mixture control, no brakes, automatic slats and automatic carb heat. I never did see a check list for it.