Throwing in the Tower; April 2000; Scientific American Magazine; by Scott; 2 Page(s)

Heaven can wait, especially if you've got a layover at San Francisco International Airport. The Bay's famous fog, a set of parallel runways designed for pre-World War II airliners and all the problems associated with 21st-century air-traffic congestion have made the airport the nation's premier site for delayed flights: last year one in three were delayed 15 minutes or more.

"We need expansion and reconfiguration," explains Ron Wilson, director of public affairs for the city's Airport Commission. Federal rules mandate that, for instrument-only flights, parallel approaches be separated by 4,300 feet, but "the only way to get that separation is to put one runway in San Francisco Bay," Wilson notes. Local groups, however, are concerned that such changes could be environmentally harmful. Thanks to land-filling, "the Bay is a third smaller than when California became a state" in 1850, explains Will Travis, executive director of the San Francisco Bay Conservation and Development Commission. "We want to see if it's possible to address the problems without putting new tarmac down."