Port of Seattle Staff Recommends No Split East Turn, Study Duwamish Flights

Flight track recommendation now goes to Port Commission, then to FAA

(Seattle)--Port of Seattle staff today recommended that Port Commissioners ask the FAA to investigate the feasibility of sending more northbound flights out of Seattle-Tacoma International Airport along a corridor over the Duwamish River. Today's staff briefing also included a recommendation that there be no further study of splitting the current east turn used for a number of northbound departures.

The study and recommendation are part of a community noise mitigation process known as Part 150, referring to the section of federal regulations that governs aircraft noise issues.

"Using the Duwamish corridor has the potential to reduce the overall number of people affected by aircraft noise," said Gina Marie Lindsey, managing director of aviation for the Port. "The split east turn shifts noise from one neighborhood to another, without reducing the overall number of people affected."

In fact, studies revealed that the number of people affected by aircraft noise could actually increase under the split turn proposal.

"We found that 30 percent more people would likely be awakened by aircraft noise if the split turn were instituted," said Lindsey. "That's a single very powerful reason to reject the split turn."

Most flights departing Sea-Tac to the north currently turn east about 8 miles north of the airport. The Part 150 Citizens Advisory Committee had recommended splitting that traffic, with half turning at about 9 miles out and the other half at the 5 mile mark, approximately over Boeing Field.

The staff recommendation on flight tracks was delivered in a Port Commission meeting held today. The Port Commission will hold a public meeting on the issue of flight tracks, and then make a final recommendation to the FAA in June.

The remaining schedule for the flight track portion of the Part 150 process is:

May 18th, 6pm, Public Hearing on flight tracks.
June 13th, 1pm, First Reading on Commission recommendation to FAA.
June 27th, 1pm, Second Reading and Final Passage of Commission recommendation to FAA.

Port staff also recommended against a proposal to use Flight Management System (FMS) technology to concentrate flight paths over very tight corridors when turning east. FMS increases impacts for those directly underneath the chosen track, but does not reduce the overall number of people affected.

"A tie is not what we're looking for," said Lindsey. "Merely shifting noise from neighborhood to neighborhood is not what we were trying to accomplish with our Part 150 work. One of the primary goals of the study is to reduce noise overall, rather than move it from neighborhood to neighborhood."

Today's report also included recommendations regarding southbound departures from Sea-Tac. Staff recommended that the FAA study increased use of a departure path over Commencement Bay between midnight and 5am.

Historically only about 30 percent of flights departing Sea-Tac leave toward the north. Largely because of prevailing weather conditions, 70 percent of flights leave to the south.

The Port of Seattle has been a national leader in reducing the impacts of aircraft noise. The Port was the first agency in the country to offer noise insulation to owners of homes near the airport. Sea-Tac was one of the first airports in the nation to require airlines to use the quietest type of airplanes, known as Stage 3 aircraft.

The Part 150 study includes many other possible remedies to reduce overall noise, including compatible land use and other operational procedures. A final commission decision on issues other than flight tracks is expected in August.

"The region gets many benefits from our airport," said Lindsey. "We want to maximize those benefits while still working to reduce the impacts that necessarily go along with air travel."