Slight thread creep here - sorry.
Originally Posted by Roffa
All the major London airports will use 2.5nm as a minimum separation on final approach when the wx is suitable and there are no wake vortex considerations.
That's obviously fairly close and it requires quite fine tuning from the ATC perspective and it doesn't take much non-compliance from the cockpit for it to reduce below 2.5nm. If it reduces to less than 2nm as happens occasionaly (not always our own fault!) we get suspended and go through the no tea and biscuits routine
I've always though that a separation minima was just that, a minima. If you only get the tea and biscuits if the spacing gets to less than 2NM then what about all of the losses of separation where spacing was between 2 and 2.5NM?
If I end up with two aeroplanes with less than the standard space between them (not half a mile - or 20% less) I'm going to be asked to explain...and pretty promptly! I guess separation means different things to different units.