G'day Dublin,
I do carb-heat on/off as part of downwind checks. I
also then re-apply carb-heat when reducing power to commence descent (i.e. base leg)
as I would for any descent! Then, I have to remember (at 200~300') to take carb-heat off in case full power needed for go-around (as per another current thread!).
I am very surprised if people don't use carb-heat on final..! This is one of the most vulnerable phases of flight: you are LOW and you are SLOW... AND the throttle is close to closed, ideal for forming carb-ice in atmospheric conditions which - lets face it - are common in the British Isles and Eire at most times of the year!
Think of the consequences of losing power on short final - when not established for a glide approach: power was planned to be needed to reach the threshold... so you will almost certainly hit the hedge or worse: at Wycombe, where I trained, we have to cross the busy M40 motorway on short final, and dropping in across 6 lanes of traffic would hurt I reckon
!
But maybe others have a different view: I'd be very interested to learn the rationale behind not using carb-heat during descent through base and final.
Cheers!
Andy
(sunglasses on as I am in Florida at present...)