Template revised April 12, 2018.
COMMISSION
AGENDA MEMORANDUM
Item No. 11a
BRIEFING ITEM Date of Meeting May 13, 2025
DATE: May 6, 2025
TO: Stephen P. Metruck, Executive Director
FROM: Keri Stephens, Director, Aviation Facilities and Capital Programs
Mark Leutwiler, Interim Director, Airport Operations
Eileen Francisco, Director, Aviation Project Management
SUBJECT: S Concourse Evolution Base Building Remaining Design Funds and Facilitating
Projects Construction Briefing
EXECUTIVE SUMMARY
The S Concourse Evolution (SCE) project at Seattle-Tacoma International Airport (SEA) will
extend the life of the S Concourse by upgrading structural, seismic, and building systems to
meet modern standards while enhancing customer experience. A multi-phased construction
approach, along with facilitating projects, mitigates operational impacts by offsetting lost gate
and holdroom capacity through short-term improvements at multiple SEA locations.
The purpose of this briefing is to provide an update on the status of the project and notify
Commission of the team’s intent to return in two weeks to request authorization of an
additional $125M for funding to complete base building design, advertise and execute a
program specific contract for special testing and inspection, amend a United Airlines (UA) lease
to support facilitating work, add scope for a new project to modify another gate for
international aircraft, and get construction authorization for 3 of the 4 facilitating projects.
PROJECT STATUS UPDATE
The base building is currently at the 60% design phase and is returning to Commission to get
additional funding to support the completion of the base building design and the construction
of key facilitating projects, including cargo and airfield infrastructure upgrades. These upgrades
are necessary to offset the impacts to aircraft holdrooms and gates being closed during the
duration of the project. To further support airport operations, the program scope will expand to
include modification to gate A6 to support larger (wide-body) types of international aircraft.
This addition will help alleviate operational demands at SEA and ensure alignment with the
airport’s long-term infrastructure needs.
This project does not increase the number of gates or increase the overall capacity at SEA but
focuses on sustaining and enhancing existing infrastructure to meet long-term operational
demands.
COMMISSION AGENDA – Briefing Item No. 11a Page 2 of 3
Meeting Date: May 13, 2025
Template revised September 22, 2016.
To keep SCE on track, additional funding is needed to keep moving towards design completion
of the base building. Several facilitating projects are necessary to mitigate operational impact
during construction and provide long-term benefits to SEA’s infrastructure.
The D6 Conversion project is a phased project that includes gates D4-D9 to support converting
the Vertical Circulation Ramp to a Passenger Loading Bridge (PLBs) at D6. The project provides
flexibility for airport operations during the S Concourse construction phases. PLBs will also be
replaced at gates D5 & D7 as they have reached end of useful life. Modification to airfield
striping and Safedock guidance systems from Gates D4-D9 will optimize aircraft maneuvering
and operations to ensure safety of passengers and employees.
The Cargo 3 project builds a Cobus parking facility to support increased bussing operations for
the hardstand and remote holdroom needs to offset the gate and holdroom closures during the
SCE project. To effectuate this facilitating project, the UA maintenance building lease
agreement will need to be amended (reduced) to support the Cobus parking facility. For UA
operations, employee parking will be relocated to the southeast of the UA maintenance facility
to ensure continued access and efficiency for airline staff.
The Cargo 6 hardstand project will convert the aircraft parking from cargo only to being able to
support both cargo and passenger operations. The work at Cargo 6 will include pavement
replacement, re-striping and operational lighting to improve safety and efficiency.
This construction approach was developed to balance several competing factors, including
minimizing disruptions to airport operations, cost efficiency, schedule alignment, customer
experience, airline support, and long-term compatibility to SEA’s facility planning objectives.
ADDITIONAL BACKGROUND
The South Concourse facility at SEA was opened in 1973 and is owned and operated by the
Port. The facility depends on building systems that are well past their useful service life, and
further development of the facility has been limited by the authorities having jurisdiction,
owing to concerns stemming from current building code minimum requirements. The building
systems and materials used in the original construction, due to their age and manufacture, are
difficult to maintain. The facility also contains areas of encapsulated regulated materials, such
as asbestos, complicating maintenance, renovation, and development. Since the South
Concourse was constructed, passenger volumes and aircraft operations have increased
dramatically, security regulations have expanded, passenger level of service expectations have
evolved, and airlines and retailers have changed their marketing strategies.
ATTACHMENTS TO THIS BRIEFING
(1) Presentation slides
COMMISSION AGENDA – Briefing Item No. 11a Page 3 of 3
Meeting Date: May 13, 2025
Template revised September 22, 2016.
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS
May 14, 2024– The Commission authorized the project to prepare design and construction
packages for facilitating projects.
October 22, 2022 – The Commission authorized to procure a Designer, GC/CM, Project
Management/Controls Support, and Commissioning Agent for SCE.
September 27, 2022 - The Commission was briefed on S Concourse Evolution and project
status.
April 13, 2021 – The Commission was briefed on SSAT Renovation Renewal PDD.
