Graham We can look at this suggestion once we get the program code itself analysed. And it is indeed used in the UK, e.g. GP can descend to 1.8A.
JamesEGNS Yes IRL strangely I had a vector from TIPOD descending to 5500ft a few weeks ago from GP. Although as mentioned, I have never in real life experience from either Scottish or London Control an altitude assignment in 100s feet.
jralston JamesEGNS hi James. This will be to do with the base of controlled airspace near TIPOD FL45. Usually you'll get 5000ft, sometimes FL50 (if QNH is really high) and sometimes 5500ft is an option.
Graham Hoggorm As of 2021, no temperature correction is applied by ATC when allocating altitude in any UK FIR.