Template revised April 12, 2018.
COMMISSION
AGENDA MEMORANDUM Item No. 11a
BRIEFING ITEM Date of Meeting January 13, 2026
DATE: December 22, 2025
TO: Stephen P. Metruck, Executive Director
FROM: Sabin Mudaliar, Acting Director, Airport Operations
Eileen Francisco, Director, Aviation Project Management
Clare Gallagher, Director, Capital Project Delivery/External Relations
SUBJECT: 2024 Flight Corridor Management Project Briefing
EXECUTIVE SUMMARY
The 2024 Flight Corridor Management Project (2024 FCMP) is intended to remove existing and
anticipated obstructions consisting primarily of trees around Seattle-Tacoma International
Airport (Airport); replant trees of compatible species, in appropriate locations; and establish
access agreements with agencies to perform obstruction management and prevent
establishment of future obstructions.
SEA operates under several federal and state regulations and requirements to ensure safe
operating conditions which include the removal of obstructions. Rigorous environmental
management practices will be implemented to minimize environmental impacts including
following the Ports tree replacement standards; and comply with applicable tree replacement
standards in surrounding jurisdictions for obstructions located outside the Airport Activity Area
(AAA). Replanting and revegetation will occur on-site where trees are removed or at nearby off-
site properties. Staff will work with the local jurisdictions on any site-specific mitigations. For this
five-year project, 197 trees were identified as obstructions. Of those, 158 are on Port property,
39 on public agency properties and none on private property.
To support effective communication and transparency with communities affected by the 2024
FCMP, a comprehensive outreach and communication plan for those areas has been
implemented and communications will continue throughout the obstruction removal periods.
This project will also look to maintain mitigation sites and replace trees that did not survive from
prior replanting efforts.
DETAILS
Purpose:
The Flight Corridor Management Program is an ongoing safety program that, approximately
every five years, evaluates and mitigates obstructions in the vicinity of the airport.
COMMISSION AGENDA – Briefing Item No. 11a Page 2 of 4
Meeting Date: January 13, 2026
Template revised September 22, 2016.
Scope of work for this authorization includes:
(1) Obstruction Removal
(2) Site Treatment
(3) Obstruction Replacement
(4) Site specific mitigations in conjunction with the local jurisdictions
(5) Monitoring & Maintenance
(6) Outreach and Communication
Justification:
SEA operates under several federal and state regulations and requirements to ensure safe
operating conditions which include the removal of obstructions. These regulations and
requirements include:
1. Federal Requirements for Airport Operators to Control Obstructions
• Federal Aviation Regulation (FAR) Part 77, “Safe, Efficient Use, and Preservation of the
Navigable Airspace”
• FAR Part 139, “Certification of Airports”
• Advisory Circular (AC) AC 150/5300.13B, “Airport Design”
• Grant Assurance 20, “Hazard Removal and Mitigation”
• Grant Assurance 21, “Compatible Land Use
2. State Requirements for Airport Operators to Control Obstructions
• RCW 14.12.020, “Airport hazards contrary to public interest”
• RCW 14.08.030, “Acquisition of property and easements—Eminent domain—
• Encroachments prohibited”
ADDITIONAL BACKGROUND
As part of previous efforts, the Port completed an aerial obstruction analysis for the 2019 FCMP
to identify the number of obstructions. In response to community feedback, Commission
guidance and consultation with the FAA, the Port used revised criteria in 2018 to identify
obstructions that had the most direct impact to safe and efficient aircraft operations. Once all
obstructions were verified by site visits, the removal and replacement work began in 2020. All
removal and replanting work were completed in 2022. Tree replacement sites on Port property
were also completed and were subject to a 5-year performance monitoring and maintenance
period for tree survival and invasive species cover.
In total, 978 trees were removed in the previous projects. The majority were on Port property
(789) with the remaining on Washington Department of Transportation (WSDOT) right-of-way
(102), other public properties (47) and private properties (40). On Port property, the Port
replanted at a 4:1 ratio, including invasive vegetation clearing to prepare sites for planting. For
other public properties, the Port paid each entity in-lieu fees for replanting at the ratio specified
by city code. For private properties, the Port offered to replace trees either on-site or on Port
property up to a four to one ratio.
COMMISSION AGENDA – Briefing Item No. 11a Page 3 of 4
Meeting Date: January 13, 2026
Template revised September 22, 2016.
The Port coordinated directly with all public and private property owners on scopes of work
specific to their properties and on permanent easements on the properties where there is
potential that additional trees may require removal in the future. The easement values were
determined by an appraiser in accordance with applicable standards for determining fair market
value.
Environmental best management practices are an integral part of the Flight Corridor
Management Program’s overall design, leaving vegetation barriers near buildings and streets,
planting low growing native varietals that will not become future obstructions, and removing and
controlling invasive species.
ATTACHMENTS TO THIS BRIEFING
(1) Presentation slides
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS
October 30, 2025 – Flight Corridor Management Program Briefing for Commissioner
Felleman.
September 18, 2025 - Flight Corridor Management Program Briefing for Commissioner
Calkins.
November 19, 2024 – The Commission authorized (1) design and
contract development for the Flight Corridor Safety Project – 2024; (2) negotiate and
obtain easements as the permanent approach for obstruction management; and (3) pay
fees to the Washington State Department of Transportation (WSDOT) and/or local
jurisdictions for them to perform replanting for obstructions identified to be removed
from their properties.
July 26, 2022 – The Commission authorized (1) advertise and execute a professional Service
Agreement for technical expertise (2) complete aerial obstruction data collection, field
verification, and obstruction data analysis (3) conduct an environmental review, and (2)
execute agreements with public agencies as needed.
April 29, 2022 – The Commission Aviation Committee was briefed on the Flight Corridor
Safety Program; program accomplishments and status; and upcoming request for
Commission authorization for the 2024 project in June 2022.
March 24, 2020 – Commission authorized adoption of Port of Seattle Resolution No. 3771,
providing for the acquisition of certain real property interests, authorizing negotiation or
condemnation and directing other actions consistent with the program and aviation
safety.
COMMISSION AGENDA – Briefing Item No. 11a Page 4 of 4
Meeting Date: January 13, 2026
Template revised September 22, 2016.
February 25, 2020 – Introduction of Port of Seattle Resolution No. 3771, providing for the
acquisition of certain real property interests, authorizing negotiation or condemnation
and directing other actions consistent with the program and aviation safety.
January 28, 2020 – The Commission authorized to (1) use existing job order contracts for
removal of current and future flight path obstructions from non-port properties and
associated replanting of replacement trees; (2) advertise and execute construction
contracts for replanting of replacement trees; (3) pay fees to the Washington State
Department of Transportation (WSDOT) and local jurisdictions to perform replanting for
certain obstructions removed from their properties; (4) execute agreements with public
agency and private property owners as needed for purposes of obstruction management;
and (5) acquire those property rights reasonably necessary for obstruction management
and preventing future creation or establishment of airport hazards.
November 14, 2017 – The Commission authorized to (1) increase the project budget for the
Flight Corridor Safety Program – Phase 1 by $2,600,000 for a new total of $5,806,000
(2) execute change order(s) in excess of $300,000 as necessary to complete the tree
removal work and (3) advertise and execute a major works construction contract to
remove invasive species and complete revegetation for Flight Corridor Safety Program
Phase 1 at Seattle-Tacoma International Airport.
February 28, 2017 – The Commission authorized to prepare environmental, design and
contract bid documents for the Flight Corridor Safety Program now-combined Phase 2
and Phase 3 at Seattle-Tacoma International Airport.
August 9, 2016 – The Commission authorized advertisement and execute a major works
construction contract for the Flight Corridor Safety Program Phase 1.
February 9, 2016 – The Commission authorized design, advertise and execute a major works
construction contract for the 2016 Flight Corridor Safety Obstruction Management
Project at Seattle-Tacoma International Airport.
November 24, 2015 – Flight Corridor Safety Obstruction Management Briefing.
