Current Initiatives

Relieving Congestion: Concourse D Annex

A new annex uses space more efficiently and accommodates our growing number of passengers.

Our Concourse D Annex project is designed to relieve current congestion for travelers waiting at crowded gates and aircraft waiting on the airfield for an open gate to deplane passengers during peak periods. The new annex uses space at Sea-Tac more efficiently to provide for passengers waiting for flights, reduces the time passengers spend waiting for a plane to arrive at a gate, saves greenhouse gas emissions from idling aircraft, and saves airlines fuel.

This project accommodates the current passenger volumes at Sea-Tac Airport with space for six holdroom gates. The 32,400 square foot building allows for what is called ‘hardstand operations,’ where passengers are shuttled to and from an aircraft parked away from the terminal building.

Moving more people with less congestion

Accessing the facility

Travelers access the facility from Concourse D, over a bridge to a two-story terminal. The sky-lighted curved roof structure is designed to be light and airy and includes a gently sloped ramp to the ground level and the departing gates. Amenities for passengers include concessions, electric charging stations, free airport WiFi, and restrooms. Passengers walk through a gate door to a waiting shuttle which takes them to the aircraft parked away from the terminal.

Arriving passengers deplane at a hardstand location, board a shuttle and ride to the new facility to a drop-off area at the south end, connecting directly into the terminal to access the bag claim level or to a connecting flight on the secure side.

Congestion Relief

Sea-Tac Airport has been the fastest growing large hub airport in the U.S. over the past five years, with passenger traffic increasing 43 percent. In the last five years, annual passenger traffic has gone from 33.2 million in 2012 to 49.8 million passengers in 2018.

With this growth, during peak periods of operation, all of Sea-Tac’s contact gates are in use – that is, where an aircraft is connected by a passenger loading bridge to the terminal.

Building Sustainably

The completed annex includes features that save energy and protect our resources.

These features include water-efficient fixtures in the restrooms and energy efficient radiant floor heating. Landscaping outside of the facility will be irrigated by water coming off of the roof.

Completion date: October 2018

Project Fact One
A waiting shuttle outside the gate will take passengers to the aircraft parked away from the terminal.
Project Fact Two
The Port is currently pursuing LEED certification for the Concourse D Annex.
Project Fact Three
Sustainable features include a rainwater management system, radiant floor heating, natural light and locally sourced materials.
Project Fact Four
95 percent of the construction waste from the project was recycled.
Checking in on the new Concourse D Annex facility at Sea-Tac Airport