Geffen.
The full original Concept of Operations is in my view the only practical option. I know, I would say that wouldn't I. The fact is I studied the options for 2 years and the quick solution (TWASS) is not practicable on safety grounds.
TWASS is not an option because... The current final director works his but off doing 44 per hour and the slightest distraction can lead to difficulties. There is ample evidence to suggest that, in fact, we need to take work load off him because the incident rate through ATC error is unacceptable. Picture this then, that instead of taking workload away from him, we add 10-15% and introduce more complexity too. That is what TWASS means, and it also means traffic turning in towards each other without a vertical safeguard on a frequency that is saturated and with a high number of foreign aircrew.
I wouldn't like to say it is impossible - that would be tempting fate but I think the only way the full ConOps could be delivered in two years would be if the Government intervened in the normal process of airspace change etc. NATS has quoted 4 years because on average that is the time it takes to complete an Airspace change (involving SIDS etc,) on the scale necessary.
I am also sure that using departure radar would enable some enhancement of departure capacity, which would then enable TEAM (6 arrivals per hour on the departure runway) to be used on a permanent basis without getting the airport out of balance. It is possible that this could be introduced in a relatively short period but that is not full mixed-mode and wouldn't deliver anything like the capacity - maybe 90 an hour with the right mix. Well, we sometimes do more than that now. It would make us a little more robust in strong winds though.
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