Port of Seattle authorizes planning for new runway at Sea-Tac International Airport on November 3, 1992.

  • By Paula Becker (with research by Daryl McClary and Walt Crowley)
  • Posted 3/21/2003
  • HistoryLink.org Essay 4007
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On November 3, 1992, the Seattle Port Commission approves Resolution 3125 to commence planning for a third runway at Seattle-Tacoma International Airport. The action follows a three-year “Flight Plan” study and public discussion conducted by the Puget Sound Regional Council. The new runway is intended to maintain airport operations during inclement weather, but it generates criticism from neighboring cities opposed to the airport's expansion.

Filing a Flight Plan

In 1988, Port of Seattle and regional transportation planners recognized that traffic at Sea-Tac was growing far faster than expected and could reach capacity by 2000. A major factor limiting airport use was the narrow separation of the two existing runways, which prevented their simultaneous use when weather limits visibility.

In 1989, the Puget Sound Regional Council (PSRC) and Port of Seattle appointed a new 39-member Puget Sound Air Transportation Committee to undertake an independent examination of alternative approaches to serving the region’s future air transportation needs. This “Flight Plan” effort examined a broad array of approaches including construction of one or more new airports and expanded rail service. The State of Washington also created a special Air Transportation Commission (AIRTRAC) to examine these issues from a statewide perspective.

A Long Roll to Takeoff

After three years of study and dozens of public hearings, the PSRC concluded that the region’s needs would be best served by construction of a new “dependent” runway at Sea-Tac International Airport to maintain flight operations in bad weather and by development of a second regional airport at a site yet to be named. The PSRC mandated stricter aircraft noise restrictions and mitigation as a condition for the additional runway.

Based on the Flight Plan conclusions, the Port of Seattle Commission voted to update its Airport Master Plan and to prepare necessary environmental studies in conjunction with the Federal Aviation Administration.

The Next Stage

Resolution 3125 also empowered Port of Seattle staff to undertake the preparation of a Master Plan Update for Sea-Tac, including the environmental impact studies, planning, engineering, and public involvement processes needed to begin construction of a third runway. The Port empanelled a Technical Advisory Committee (TAC) to advise the Master Plan Update process. The Committee held five public sessions between July 1994 and July 1995 to review air traffic forecasts and facility issues. The TAC was composed of more than 40 members including representatives of the anti-third-runway Airport Communities Coalition and Regional Commission on Airport Affairs, the Federal Aviation Administration, Puget Sound Regional Council, Puget Sound Air Pollution Control Agency, and other Washington State agencies.

As part of the Master Plan Update, the Port also established “Sea-Tac University,” an innovative citizen participation process for in-depth discussion of air transportation matters. Sea-Tac University held nine public sessions broadcast on government access channels throughout the region. In addition, the Port conducted four special Planners Forums to brief and involve city planners from Sea-Tac area cities and the Highline School District.

In addition, Master Plan Update issues were reviewed and discussed at 10 public Port of Seattle Commission meetings between 1993 and 1994, and Port staff made more than 50 presentations to civic and community groups. Over the course of the Master Plan Update process, the Port mailed regular editions of Airport Forum newsletter to a mailing list of 27,000 Sea-Tac area residents and circulated their News Flash update publication to local elected officials. The Port also published two special daily newspaper inserts, each reaching a combined circulation of 400,000 and generating more than 1,500 responses from citizens. In addition, detailed “Project Notebooks” were placed in 17 local libraries for citizen reference.

Despite these efforts, the planning engendered opposition from municipalities and communities near Sea-Tac (organized as the Airport Communities Coalition) concerned over the filling of wetlands and other runway-related impacts. The first permit application for the third runway in 1996 triggered lengthy regulatory reviews and extensive litigation. In May 2004, the State Supreme Court largely cleared the way for construction to resume, and on August 19, 2004, the Airport Communities Coalition dropped litigation, after having spent $15 million over 10 years campaigning and litigating against the third runway.

Construction resumed and the 8,500-foot runway opened in November 2008, at a total cost of slightly more than $1 billion, more than four times the original estimate.


Port of Seattle Resolution 3125, November 3, 1992; "General Chronology Related to Regional Commercial Aviation Development in the Central Puget Sound Region," Puget Sound Regional Council memorandum, May 9, 2002; “Regional Air Capacity -- Public Involvement History,” Port of Seattle memorandum, July 29, 2002; “Seattle-Tacoma International Airport Detailed History of the Third Runway Planning Process,” Port of Seattle Memorandum, October 3, 2002); “The Flight Plan Project, Final Environmental Impact Statement,” Puget Sound Regional Council and Port of Seattle, October 6, 1998; Larry Lange and Jeffrey M. Barker, "You Know That Third Runway? Sea-Tac's Really Getting It," Seattle Post-Intelligencer, August 20, 2004, p. A-1.
Note: This essay  was updated on August 29, 2004, and on November 20, 2013.

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