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Why Has SFO Got Such Goofy Runways?

Pick your culprit: airport management, the FAA, environmentalists, politicians, or the even the Bay itself.

As the investigation into Saturday's crash of Asiana Flight 214 continues, the cause of the catastrophe—and of the deaths of two of the passengers—is still not certain. But with many eyes on SFO in the last few days, another question arose, at least to us. Just why are the runways at SFO so oddly-designed in the first place? You have the geography of the Bay's shoreline to thank for that, but responsibility also goes to a coalition of environmentalists and politicians for keeping them that way.

The current runways at SFO form a double-lined X, as you can see in the FAA diagram here. That creates a headache for scheduling takeoffs and landings, since the trajectories of the planes can't intersect. Air traffic control at SFO is an advanced exercise in knitting. As anyone who's ever flown in or out can tell you, the runways also run right up against the water of the bay, as opposed to being surrounded by land. This kind of runway design is relatively rare, at least among major U.S. airports. Oakland International Airport has one runway, with more landfill surrounding it on all sides. LAX in Los Angeles has four runways, but they all run parallel to each other. John F. Kennedy Airport in New York has four runways running two and two like SFO, but at JFK they are offset, meaning that only one crosses perpendicular to the others. Even Chicago O'Hare, with seven runways, only has three points of intersection, compared to four intersections at SFO. Our airport's runways have another design oddity. They're really close together—only 750 feet separate each pair. Federal guidelines require 4,300 feet of distance for simultaneous operation in poor weather. The parallel pairs are so close together that when the fog comes in, planes are staggered, only using one at a time, leading to plenty of delays.

So why are our runways so, well, hinky? The short answer is that the contours of the Bay make it hard to spread them out in a more reasonable fashion. But it's not for lack of trying. Starting in 1998, as tech-bubbled fueled demand increased at SFO, plans circulated to increase capacity by filling in up to two square miles of the Bay and building out new, better-designed, runways. Under one of the most plausible options (see page 13 of the pdf), SFO would have extended one of their runways and built two more on landfill in the Bay. The runway, 28L, on which the plane crash happened this weekend would have been converted to a taxi way. Although according to SFO documents filed with the San Francisco Planning Commission (see page 16 of the pdf), runway 28L was built for use by smaller Boeing 747 planes, according to Boeing documents (see pages 16 and 17 of the pdf), the required landing distance for a 777 is well within the capacity of the current runway.

But like many development projects, especially those involving the water, the plans never made it to liftoff. A coalition of environmental groups, including the Sierra Club and Save the Bay rallied opposition to the project by arguing that the damage to the watershed would be too great to offset the benefits. Though then-Mayor Willie Brown supported the project, it ran into heavy fire at the Board of Supervisors, including from Brown's rival, Supervisor Aaron Peskin. The economic downturn, plus a 2008 SF Board of Supervisors resolution, put the final nail in the project's coffin, ensuring that the runways will remain in the present configuration for the foreseeable future.

Did oddness of our runways contribute to the crash? Former airline caption Chesley "Sully" Sullenberger told KCBS recently that FAA mandated construction to increase the space around the runways that acts as a safety buffer, "certainly is something they'd be looking at." A recent administrative decision by the FAA requires an increase in the buffer zone, which can help protect planes if they undershoot a runway. SFO is not currently in compliance with those standards, but is working to do so. Today on Slate, pilot Patrick Smith argued that the runway configuration may have made the landing, "trickier than normal" but that it was by no means "unsafe." In any case, he went on to say, it was far too early to speculate. 

If the proposals to extend the runways into the Bay had been enacted, could the crash have been avoided? I put the question to Geoffrey Gosling, the Principal of Aviation System Consulting in Berkeley, who had consulted for SFO on air traffic control during the expansion project. He sounded strong notes of caution and skepticism that, saying that, "attempting to infer how the runway reconfiguration project, had it been built, might have affected the outcome of the accident earlier this week will necessarily be highly speculative. Obviously, had the project been built the situation faced by the flight crew would have been different and we cannot know how this might have changed their decisions and actions, much less the course of events."

Still, the "what ifs" will certainly linger. Whether they're persistent enough to reawaken SFO's dormant expansion plans is an open question. The airport's representatives could not be reached for comment.

 

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