The Kabaka,
It is not much use only to be able to do CDAs from 6000ft. What is needed is for all aircraft to be able to do them from TOD to around 1500ft to 1000ft without intermediate level outs and without overall loss of airport capacity. The systems I gave references for in my last post may be able to achieve that one day. In fact London Heathrow has nothing to boast about; according to the Eurocontrol Performance Review Report for 2008 (
www.eurocontrol.int/prc) on page 59 in Fig 72 it is shown to have the worst performance, in terms of additional time spent on the approach, of any major airport in Europe!