Use of carb heat
We're having a bit of an argument at my school on standardising the use of carb heat on the final approach.
The other 2 instructors are teaching to apply carb heat when starting the approach on base, then on short finals at about 2-300' to put it back to cold so you have full power in the event of a go around or touch and go.
Surely if you are using carb heat there is some risk of carb icing, or you would not be using it at all. How does this risk go away in the final 2-300' of an approach? I have always been taught to leave it on, then if doing a touch and go move it to cold before applying full power, or if not leave it until the after landing checks. Since the store bought check lists state carb heat cold as an after landing check, this would seem to back me up.
I should probably say we operate PA-28s with lycoming engines.