I am a bit confused about the basic rules for altimeter settings. I do all my flying in the UK at the moment:
1. Why does ATC say 'altimeter 2992' and what is the significance of this?
2. My altimeter when flying from Stansted to Heathrow said 700 feet lower than my 'actual' height (checked by using Shift-Z)
3. How do you set the altimeter to read 0 feet at aeordrome level? Why do this, is it even a good idea, is it best to do something else?