I have a bone to pick on the Carb heat usage issue, my friend recently totaled his plane and was incredibly lucky to walk away from the wreckage. Also, I recently read a CAA accident bulletin about a fatal crash in North Wales both incidents happened on final and both were attributed to carb ice.
I understand that instructors and flight manuals alike call for a “check” for the need for carb heat upon approach. Here is my question why not put the carb heat on just prior to entering the pattern and power reduction AND LEAVE IT ON right up to short final and the runway is assured and where if you need full power for a go-around you have it and you will not be getting unfiltered air if landing on a dirt strip.
What’s the downside of leaving it on throughout the entire pattern till short final compared to the risk of picking up icing late on finals after you have "checked" for it back on the downwind and returned it to cold?