has some MASSIVE ATC problems, be it for fog reasons or whatever, but their air traffic problems due to their intersecting runways are terrible
>>>as the runways are obviously far enough apart that under normal conditions, both can be used
It was 3 years ago today that SWA operated its last flight at SFO
(after 19 years there) so SFO
delays are a subject I know well.
The use of intersecting runways is -NOT- what drives the delay situation there at SFO
. The real "whatever" reason is in your second statement, i.e. the runway centerlines are fine for normal conditions (VMC), but for anything less than VMC, the delays come.
's ability to handle traffic (airport acceptance rate, AAR
) is usally about 60 per hour, and that's based on an optimum runway configuration of visual approaches to 28L and 28R, and departing on 01L and 01R. The ATC folks there do a masterful job of synching departures with arrivals, and it's pretty damn impressive. They'll have 2 aircraft position-and-hold on 01L/R (cocked) and just as soon as the two landing on 28L/R clear the intersection, ATC will launch the two departures off 01L/R with diverging turns once airborne. It's almost like watching cat shots on a carrier--it's so well orchestrated.
The problems start when aircraft approaching 28L/R lose the ability to shoot visual approaches, and the trigger for this is anything lower than about a 2,500 foot ceiling and/or 5 miles of visibility. Once they lose visuals (VAPs), you'd think the alternative is to simply go to ILS approaches to 28L and 28R, since they both have them installed. Problem is, to shoot parallel ILS approaches, you need a minimum of 2,500 feet between the runway centerlines, and 4,300 feet if shooting simultaneous ILS approaches. At SFO
, you can't do either, since the 28L/R centerlines are only 600-700 feet apart.
When you lose the ability to do VAPs, SFO
essentially becomes a single runway airport for landing, and the 60 AAR
drops (rather suddenly) to 28-30. If they lose VAPs with 60 aircraft in the air, half of them are going to have to hold (or maybe divert) and anything that hasn't left it's departure point will get held on the ground (at LAX
, wherever) until revised slot times are determined.
The old DEN
Stapleton had the same sort of problem with 17R/35L and 17L/35R in IMC conditions, and they solved the problem by building the new airport on about 80 gazillion acres where runway separation is no longer a problem. There's been some discussion about moving SFO
's 10L/28R further north, out onto new land they'd have to reclaim from the Bay, but that's years away, if ever.
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.