Originally Posted by
misd-agin
Yeah, it works when there's hardly any traffic - "oh this works great! Why don't they do that in XYZ airport in the U.S.?" Add U.S. level of airport movement and it falls apart.
The difference in workload in the U.S. ATC system vs. the 'busy' European cities is almost night and day. A 'busy' period overseas is an easy day at work for U.S. based pilots.
From the tower controller point of view, it is far more difficult to operate a VFR system than an IFR system. The same vectoring often has to be done but on one frequency and using different methods.
As for 'hardly any traffic'. Heathrow has only two mainly single mode runways. If it were to operate 5 runways as Atlanta at the same runway acceptance rate it currently achieves on two with mandatory IFR then it would significantly surpass Atlanta's traffic. The local frequency would be just as unhurried as it is today.
Gatwick has one multi-mode runway if it were to operate 5 runways each with the same acceptance rate that it achieves on one mandatory IFR, then it would also far surpass Atlanta's acceptance rates.
The problem would be in the marshaling of all those aircraft and their ground handling. However, the frenetic verbal activity that can be heard at some airports working VFR would not be present.
With the new trajectory based precision navigation systems being developed the event driven VFR concepts may cease to be required.