Originally Posted by
sharpend
Well, having my first solo in 1959 and left the RAF in 2003, my memory is fading so perhaps more learned pilots will correct me. But here goes: You change to 1013 at Transition Level which is normally 3000 feet QNH. In the USA, by the way, it is 18,000 feet. I think the London control zone use to be 4000 feet. I think quadrants are now gone and we operate semi-circulars.
You change to 1013 at the transition ALTITUDE, which varies throughout the UK but is 6,000ft under all TMAs and mostly 3,000ft elsewhere.
A common transition altitude is being considered for the whole of the UK to bring it in line with other Eurocontrol countries, possibly either 10,000ft or 18,000ft but no decision has yet been made.
Hopefully the RPS system will be dispensed with when it happens.