Way back in the late 1960s when I was instructing on the Varsity, one exercise practiced by instructors was to make an approach to land without an ASI (simulating pitot icing or some other failure). You would be under the “hood” while the safety pilot had full visual and full instruments. You flew by attitude, power, etc, and if all was in the grove by around 200 feet, you were allowed to look up and land.
Frankly, it wasn’t difficult given adequate practice, but a very useful exercise nonetheless. The Varsity was a primitive design (direct development from the WW2 Wellington) so failures were not unknown. However, only once did I have to carry out a “no ASI” landing for real.
I guess such training exercises are totally alien to the modern generation of pilots.
Jack