Originally Posted by
PukinDog
San Francisco's runway 28L and 28R centerlines are 750' apart, so aircraft affirming they can maintain visual separation is the only way they can conduct simultaneous, parallel approaches, and it's not as haphazard as "doing Sight and Follow" either day or night: The aircraft in both streams are assigned altitudes, speeds for in-trail separation, and vectored up until final approach intercept in the same manner as one would be for an ILS. ATC usually feed them onto the final approach so they come down in slightly staggered pairs within easy sight of each other. In visual conditions and /w TCAS, it's an easy task to see who you're following and who you're forming-up with on the parallel runway. Also, in FAA-land even while on an instrument flight plan including the instrument approach, in Visual Meteorological Conditions the crew is still responsible for maintaining a visual watch to see and avoid other aircraft.
Which is where the "maintain visual separation" part comes in. In VMC, given the altitude, speed control for in-trail, and vectors to intercept final approach you'll receive from ATC, the only thing you're being asked to ensure is something you should, by regulation, be doing anyway; not overshooting your final turn and maintaining visual separation from the guy who's going to join the parallel final in case he does. This is done literally hundreds of times a day and night, weather permitting. There's an ILS LOC on each to back up the visual final, but obviously the focus during join-up is outside on the other aircraft.
Check Airman is correct. Somebody at a desk wrote an SOP not knowing that this common practice of "maintaining visual" exists for SFO due to the extra-close parallel runways, and when they have 100+ mile streams of inbound aircraft for 2 runways, upsetting the flow so 1 can shoot an ILS puts the airport into a single approach/runway operation, shutting the parallel down. Even if they did, being VMC they'd still have to look outside and watch for other aircraft. Their SOP does not relieve them of that responsibility.
The airport isn't going to prioritize or stuff-up their expeditious arrival flow for 1 Company's SOPs. I believe when the Controller asked Lufthansa not if he could "accept a visual approach" but rather "could he maintain visual separation" he was trying to help the guy out since the Controller knew he's required to do that anyway in VMC conditions. But then Lufthansa said that he couldn't even maintain visual separation, so his fate was sealed.
The strange thing is Lufthansa will have been doing this exact same flight at this time everyday for years! Unless this is a new policy how is it that this is the first instance this has happened?