Beginning in 1988, the Port of Seattle and other planners forecasted that Sea-Tac could reach all-weather capacity by the year 2000. Because Sea-Tac’s two parallel runways were built only 800 feet apart, only one could be used when cloud cover was lower than 5,000 feet or visibility was less than five miles. This condition prevails approximately 44 percent of the time and resulted in flight delays and higher costs to airlines and their passengers.
The Port of Seattle and Puget Sound Regional Council conducted a public study of this problem between 1989 and 1992. Known as "Flight Plan," the three-year effort entailed extensive citizen outreach and technical analysis of numerous options for meeting regional air travel needs through 2020. In 1996, the Regional Council narrowed its “preferred alternative” to the third runway and to development of a “major supplemental airport,” and formed an independent Expert Arbitration Panel to review potential sites.
Nowhere to Land
The search began with 41 options, which were narrowed to 19 and then to a dozen. Final possibilities considered were commercial airline use of Snohomish County's Paine Field in Everett and McChord Air Force Base in Tacoma, and existing airports or new sites in Arlington, Marysville West on the Tulalip Reservation, Marysville East due north of Lake Stevens, Bothell/Mill Creek, Duvall, Redmond, Lake Sawyer near Black Diamond, Enumclaw, Fredrickson, and Tanwax Lake.
All of these sites posed various logistical problems, and the neighbors of most candidate sites adamantly opposed their expanded commercial use. By the fall of 1994, it became clear to the Panel and its consultants that none of the sites were practical.
Resolution EB-94-01 also reaffirmed that planning should proceed for a third runway at Sea-Tac, provided that further study proved that a third runway could satisfy demand, meet noise reduction standards, and not cause irreparable environmental harm.