PSRC 3rd Runway Decision Process



JUNE 20, 1996

The purpose of this document is to summarize: (1) the planning that has been undertaken to provide for the long-term commercial air transportation capacity needs of the central Puget Sound Region; (2) air travel demand forecasts and need; and (3) the environmental process for the Council’s regional planning decision.

1. Commercial Air Transportation Planning


The first regional aviation plan was completed in the late 1960s and has been updated periodically. The 1988 Regional Airport System Plan (RASP, adopted by the Puget Sound Council of Governments, forerunner to the Regional Council), looked at the components of the regional airport system, and offered a detailed series of recommendations regarding commercial aviation and general aviation. The 1988 RASP recommended that planning be conducted to address commercial aviation needs and then, if needed, adjustments could be made to general aviation capacity at airports that might potentially be impacted by the conclusions and recommendations from the commercial aviation studies.

The 1988 RASP recommended that Puget Sound Council of Governments, in cooperation with the Port of Seattle as the operator of Seattle-Tacoma International Airport, should complete a detailed evaluation of the region’s long-term commercial air transportation needs. This effort resulted in the Flight Plan Project (1989-92) and subsequent decision processes and studies. The Regional Growth and Transportation Strategy (VISION 2020) adopted in 1990 recognized the 1988 RASP as the interim air transportation element of the Regional Transportation Plan (now called the Metropolitan Transportation Plan) “until a new plan is adopted.” (PSCOG Resolution A-90-01). This action was reaffirmed by the Regional Council through approval of the “Interlocal Agreement for Regional Planning of the Central Puget Sound Area” dated September 30, 1991.

Flight Plan

The Flight Plan Project was concluded in 1992. The purpose of Flight Plan was to develop a solution to meet the region’s commercial air travel needs to the year 2020 and beyond. Based upon its two-and-a-half year effort to examine ways to accommodate demand and the environmental impacts of the studied alternatives, the Flight Plan Study recommended a multiple airport system that included a new runway at Sea-Tac Airport.

Sea-Tac Master Plan

As a result of Flight Plan, in November 1992, the Port of Seattle Commission adopted Resolution No. 3125, As Amended, which adopted the Flight Plan recommendation pertaining to adding a dependent air carrier runway at Sea-Tac Airport and directed Port staff to undertake the necessary detailed studies and a project-specific environmental impact statement. A comprehensive update to the Sea-Tac Airport Master Plan was undertaken to evaluate the long-term facility needs at the airport and to

develop an array of possible improvements for efficiently meeting forecasted regional air travel demand to the year 2020. In February of 1996, the FAA and the Port of Seattle, as co-lead agencies, published an environmental impact statement for the Master Plan Update which evaluated potential environmental impacts and identified mitigation measures for proposed airport improvements, including a new runway.

Major Supplemental Airport Study and Expert Panel Evaluation In April of 1993, after studying the conclusions of the Flight Plan report and environmental review documents, and in an effort to find the best method of meeting the region’s long-term commercial air transportation needs, the Regional Council General Assembly in April 1993 adopted Resolution A-93-03, which called for the region to pursue both a major supplemental airport and, subject to conditions, a third runway at Sea-Tac International. These conditions were: (1) the feasibility of a major supplemental airport and whether it could be put into service in time to eliminate the need for a third runway; and (2) implementation of noise reduction objectives; and (3) feasible demand and system management actions. The major supplemental airport was subsequently defined as being of sufficient size to accommodate two parallel runways capable of independent operations. The noise reduction objectives and demand and system management actions were to be independently evaluated. A determination of whether these conditions were satisfied was to be made no later than April 1, 1996.

Resolution A-93-03 was followed by Executive Board action adopting specific Implementation Steps for carrying out the resolution’s requirements. Among the provisions of the Implementation Steps was the establishment of expert panel(s) to perform the independent evaluations of demand/system management and noise issues. The noise issues to be analyzed were limited to impacts associated with the existing facilities at Sea-Tac. The issues did not include any analysis of noise impacts related to a possible third runway.

In October of 1994, after receiving a consultant’s report on potential new airport sites, the Regional Council Executive Board adopted Resolution EB-94-01 which concluded that no feasible sites for a major supplemental airport could be found in the four-county region. That resolution marked satisfaction of the first condition for authorization of the third runway in Resolution A-93-03. Through Resolution EB-94-01, the Board recommended cooperative actions by the state, local governments and regional transportation planning organizations to examine whether other options such as high speed rail could meet the region’s long-term air travel and inter-regional ground travel needs.

An Expert Arbitration Panel was appointed in June 1994 by the Secretary of the Washington State Department of Transportation (WSDOT) to make findings on the satisfaction of the Demand/System Management and Noise conditions.

In May of 1995, the General Assembly of the Puget Sound Regional Council adopted the Metropolitan Transportation Plan, which incorporated Resolution A-93-03 as an appendix and included the third runway at Sea-Tac subject to satisfaction of the conditions for noise reduction and demand and system management actions by April 1, 1996.

In a series of written orders on Demand System Management Issues, concluding with its final order in December of 1995, the Expert Panel found that congestion pricing, gate controls, high-speed rail and more readily achievable improvements in existing rail service could not reasonably be relied upon as a justification for obviating or deferring the construction of the new runway at Sea-Tac and therefore are

not “feasible” demand and system management steps within the meaning of the PSRC Resolution, even though these improvements if achieved, would likely produce significant benefits to the region.

Consequently, the demand/system management condition of the Resolution was satisfied.

In its final order of March 27, 1996, the majority of the Panel concluded that “although the Port of Seattle has scheduled, pursued, and achieved an impressive array of noise abatement and mitigation programs, the Port has not shown a reduction in real on-the-ground impacts sufficient to satisfy the noise reduction condition imposed by Resolution A-93-03.” Thus, because the noise condition was not met by April 1, 1996, the Metropolitan Transportation Plan (MTP) currently does not provide for a third runway at Sea-Tac Airport or provide any other means for meeting the region’s acknowledged long-term air transportation capacity needs.

The Panel concluded “that the Port could have done more, and that, had it done so, the additional improvement probably would have made a material difference in real, on-the-ground noise impacts, turned a marginal improvement into a meaningful one, and therefore affected the final outcome of this proceeding.” In conclusion, the Panel offered a list of recommended noise reduction measures to be considered.

Regional Council Follow-up to Expert Panel Decision

At its April 25, 1996 meeting, the Executive Board of the Puget Sound Regional Council agreed to use the recommendations in the Panel’s Final Decision on Noise Issues (March 27, 1996 pp. 37-41) as the basis for deciding what additional noise reduction measures should be part of including a proposed third runway at Sea-Tac Airport as an amendment to the Metropolitan Transportation Plan (MTP). The Board directed staff to initiate the process to include a third runway at Sea-Tac and

“…provide for (a) additional noise reduction measures, based on the recommendations of the Expert Panel; (b) establishment of a plan for implementation of such noise mitigation measures, including milestones; (c) monitoring compliance with such implementation plan; and (d) an agreement between the PSRC and the Port of Seattle for implementation of such plan…”

Agencies and communities that could be responsible for implementing the Expert Panel recommendations prepared written responses to the Panel’s recommendations, and the Panel recommendations and responses were discussed at an Executive Board workshop on May 30, 1996. Written public comment on the Panel recommendations also was encouraged; this correspondence was distributed at the workshop.

A Resolution of the General Assembly of the Puget Sound Regional Council amending the Metropolitan Transportation Plan (MTP) to include a third runway at Sea-Tac Airport with specific noise reduction measures based upon the recommendations of the Expert Panel was distributed to the Council’s Executive Board on June 20, 1996, for action at the Board’s meeting on June 27, 1996. Following action by the Executive Board, the Regional Council General Assembly will consider the Executive Board’s recommendations on Thursday, July 11, 1996.

2. Commercial Air Travel Demand Forecasts and Need The Flight Plan Project concluded that the existing Sea-Tac airfield would not be adequate to meet regional air travel needs past the year 2000.

Growth at Sea-Tac is being driven by strong regional population and economic growth, along with the region’s reliance on air travel. The Puget Sound region’s population nearly doubled between 1960 and 1990. By 1995, the region’s population eclipsed three million, and an additional one million people are projected to be here by the year 2020.

Forecasted aviation needs at Sea-Tac International, which serves most of the commercial passenger and cargo aviation needs for the region and much of the state, have been subsequently updated in the Port of Seattle Master Plan Update Technical Report No. 5, April 12, 1994.

The table below shows that projected annual passenger volumes for the region are expected to double between 1993 and 2020. However, during the same period, the number of aircraft operations that are forecasted to handle these passengers (the measure most directly related to runway capacity) is forecast to increase by about 30 percent. This more moderate trend in the growth in aircraft operations is largely due to the expected replacement of smaller aircraft, especially commuter aircraft, with larger aircraft.

The capacity and current efficiency of the airfield at Sea-Tac International is determined by the rate at which aircraft can arrive and depart using the two existing runways, in one hour. This rate is then annualized using a level of acceptable delay for each arriving or departing operation that is based on local weather conditions and the daily operational demand profile experienced at the airport. Using this method, the efficient annual capacity is calculated to be about 380,000 operations (arrivals and departures).

Aviation Trends and Forecasts* Four-County Puget Sound Region-All Airports Forecast Measure Current And Forecast Period 1993 2000 2010


Air Passenger Activity

Total Annual Passengers (Millions)





Annual Aircraft Operations





Air Cargo Activity

Sea-Tac International






(1990) 22,199

35,249 —


*Sources Master Plan Update, Technical Report No.5, April 12, 1994 Port of Seattle; Project II Report, October 1992, A-I Washington State Air Transportation Commission.

The forecasts suggest that Sea-Tac International will reach its efficient operational capacity around the year 2000 but the actual aircraft operations for 1995 were 386,500, exceeding the year 2000 forecast.

Additional operations can be accommodated but only with increased average delay.

The airport’s capacity is greatly affected and reduced by regional weather conditions. Poor weather, which occurs about 40-45 percent of each year, affects air traffic safety procedures and reduces the airport from operating two streams of arriving aircraft to one stream. This reduction occurs because the two existing runways are too close together (800 feet between centerlines) to both be used for landing aircraft during periods of poor weather. A third runway appropriately separated from the existing runways would help eliminate this problem and provide capacity to land aircraft in poor weather.

In addition to runway and airspace capacity, airport capacity is also bounded by airport terminal capacity and ground access capacity. These three constraints (airspace, runway, and terminal/ground access) were addressed in the Port of Seattle’s airport Master Plan Update, with the ground access issues also addressed in the highway, transit and freight and goods elements of the updated regional MTP.

3. Environmental Process

The Regional Council is amending the Aviation Program and Appendix F, Resolution A-93-03 of the Metropolitan Transportation Plan (MTP) to include a third runway at Sea-Tac Airport with specific noise reduction measures.

The Regional Council has used two environmental impact statements previously published to assess the potential environmental impacts of its action: The Flight Plan Project Final Environmental Impact Statement (1992) and the Final Environmental Impact Statement for Proposed Master Plan Update Development Actions at Seattle-Tacoma International Airport (1996). The Regional Council has also published an Addendum which provided additional information/analysis, but which did not substantially change the analysis of significant impacts and alternatives in the existing environmental documents.

The use of the two prior environmental impact statements and an Addendum is authorized by the SEPA rules. The Regional Council is required to prepare a supplemental EIS if, subsequent to publication of the Port’s EIS, there have been substantial changes to the proposal; there is new information indicating the proposal’s probable significant adverse impacts; or the Regional Council discovers misrepresentation or lack of material disclosure in the EIS. See WAC 197-11-600(3)(b) and (4)(d).

The Regional Council has reviewed both the Flight Plan EIS and the Master Plan Update EIS, particularly with regard to the Regional Council’s broad regional planning issues, and determined that the environmental impact statements are adequate for the current regional planning decision. The Regional Council also sought to determine whether there was any new regionally significant information subsequent to the Master Plan Update EIS which would trigger a requirement for supplemental environmental review. The Regional Council did not identify any such information.

Because the Regional Council is acting on the same proposal for which the prior environmental impact statements were prepared, formal “adoption” of those documents was not necessary.

See WAC 197-11-600(4)(a).