alf5071h actually I did not write that, however I will try to answer your question.
Under VFR conditions, good VFR such as ceiling greater than 5,000ft and five miles, many more aircraft can land and takeoff in any given time period because the ATC can use visual separation for traffic rather than the standard IFR/radar separation.
A good case in point is St. Louis (KSTL) airport. The runways are too close together to allow parallel approaches under IMC operations, therefore in IMC the landing operations are nearly cut in half when compared to VMC operations. The same problems exists for departures, the controllers can depend on the pilots to provide visual separation with the instructions of, “Cleared for takeoff, keep the aircraft in front of you in sight.” Or something like that. When the aircraft in question have similar operational profiles both aircraft came climb on the same vector, with slower aircraft one of the two are given a turn to assist in separation. An excellent airport to observe how effective VMC operations can be is Chicago O Hara (KORD). I truly believe that the best air traffic controllers in the world work at KORD; they are akin to poetry in motion.
I have always been under the impression from my experience in Europe that the same separation standards are used regardless of the weather conditions; I very well could be mistaken. I realize that overall the weather is generally better in the US and we have a lot more airspace. There is an advantage of always using standard IFR separation regardless of weather conditions, which is of course knowing the precise number of aircraft operations per hour one can have at any given airport. However this does little to promote traffic flow.
When weather conditions exists I will always request a visual approach, however, if there is a precision approach available for the runway I will have it on the flight director and monitor the approach while performing the visual approach. This is just good common sense. In the absence of a precision approach one must use situational awareness to help determine alignment on the proper runway, such as knowing which side of the runway the taxiways and buildings are on as in the case of Rapid City (KRAP).
I in no way believe that the fact that I have 21,000 hours will prevent me from having an accident or incident, however the fact that have never had an accident or incident in those 21,000 hours shows that I have been doing something right and I would be a liar not to also admit that sometimes good old fashion luck has played a role in my career. Any pilot near my experience level that claims lady luck has not helped them is a liar. At least in my humble opinion.
Any way I hope this helped clear up any questions you had on the subject of visual approaches here in the US.
PS everybody knows that Al Gore invented the internet, he said so!
