AGENDA MEMORANDUM                        Item No.          6a 
ACTION ITEM                            Date of Meeting    September 12, 2017 
DATE:     August 24, 2017 
TO:        Dave Soike, Interim Executive Director 
FROM:    Michael Ehl, Director, Airport Operations 
Wayne Grotheer, Director, Aviation Project Management Group 
SUBJECT:  Ground Based Augmentation System (GBAS)  CIP#C800834 
Amount of this request:               $4,568,000 
Total estimated project cost:          $4,588,000 
ACTION REQUESTED 
Request Commission authorization for the Executive Director to (1) design, advertise and
execute a major works construction contract, (2) execute a contract with Honeywell for
advanced system features, (3) advertise and execute a contract for the development of flight
procedures,  and  (4)  enter  into  one  or  more  agreements  with  the  Federal  Aviation
Administration (FAA) for the performance of flight checks, certification, and other support
needed for the Ground Based Augmentation System (GBAS) at Seattle-Tacoma International
Airport (Sea-Tac) in the amount of $4,568,000 for a total estimated project cost of $4,588,000. 
EXECUTIVE SUMMARY 
This project will upgrade Sea-Tac's Ground Based Augmentation System (GBAS, a satellite based
navigational aid), from a beta system to a fully functioning navigational aid. GBAS will provide a
resilient alternative to reliance on old-technology navigational aids and their limitations. In
addition,  there  are  potential  future  environmental  benefits  if  a  steeper  glide  slope  is
implemented.  A number of airlines that operate out of Sea-Tac actively support this project. 
JUSTIFICATION 
This project will provide upgraded navigational aid technology at Sea-Tac, in the form of GBAS.
Aviation is moving away from sole reliance on navigational aid technology developed in the
1930's, to modern navigational aid technology that uses global positioning system (GPS). The
Port of Seattle has been a leader in this arena, with the Greener Skies Over Seattle project. The
Port also invested in transformative navigational aid technology in 2003 (beta system), known
as Local Area Augmentation System (LAAS). GBAS receives standard GPS signals, corrects them
for accuracy then broadcasts them back to aircraft approaching and departing the Seattle area. 


Template revised September 22, 2016.

COMMISSION AGENDA  Action Item No. __6a__                              Page 2 of 5 
Meeting Date: September 12, 2017 
This request is to upgrade the existing beta system to current standards. The existing LAAS
system software/hardware was initially installed by Honeywell over 10 years ago. The original
2001 contract with Honeywell (the only FAA certified GBAS vendor) included  a free
software/hardware upgrade to the LAAS system in the future which Honeywell is still honoring
as part of their original  contract agreement.   Honeywell will install all the necessary
software/hardware items at no cost to the Port. T his one-time system upgrade is valued at
approximately $1.8 million. There are some enhanced features beyond what is included in the
free upgrade that will allow Sea-Tac to operate in low visibility conditions. The  Port will
purchase these enhanced features from Honeywell as well as the infrastructure, training and
maintenance needed to support the new equipment. 
Timing is right for this project as airlines are purchasing aircraft with GBAS Landing System (GLS)
technology built-in (GLS technology comes standard on all Boeing aircraft and as an option on
Airbus aircraft), and in some cases retrofitting old aircraft with the technology. Several airlines 
operating at Sea-Tac have made a commitment to use GBAS once it is available.  There are
multiple benefits of using GBAS to the airlines and Sea-Tac; the most prominent benefit is the
single system can provide approach capability to every runway end at Sea-Tac.   Current
navigational aid technology uses an independent system for each runway that can be affected
by objects in proximity.  Therefore Sea-Tac will realize an immediate positive operational
benefit from adding GBAS.      Other potential future benefits of GBAS are the positive
environmental benefits realized from planes landing at steeper glide slopes. Implementation of
a steeper glide slope would require development of new procedures and FAA approval.  The 
request for a single authorization of design, advertisement and execution of a construction
contract is for efficiency in the project delivery. Port staff will likely be utilized to complete the
design documents. 
DETAILS 
The GBAS system that the Port will have at the conclusion of this project will support aircraft
landings during periods of lower visibility that are not unusual for Sea-Tac.  Honeywell has 
developed and is seeking FAA certification on a system that will support aircraft landings during
periods of extreme low visibility that occur at Sea-Tac less than 5% of the time. The system that
will be installed by this project will allow it to be upgraded in the future so the system can be
used for navigation during extreme low visibility conditions. Port staff will likely be utilized to
complete the design documents. 
Scope of Work 
The scope of this project is to install all infrastructure necessary to support the GBAS upgrade
which is located on the airfield (shown in the presentation). 

Template revised September 22, 2016; format updates October 19, 2016.

COMMISSION AGENDA  Action Item No. __6a__                              Page 3 of 5 
Meeting Date: September 12, 2017 
Key scope elements include: 
(1)   Replace existing electronics 
(2)   Install new fiber optic cable 
(3)   Install up to four new GPS receiver antennas. 
(4)   Replace the existing broadcast antenna. 
(5)   Contract with a third party to develop new GLS flight procedures that mirror existing
approach procedures at Sea-Tac. 
(6)   Contract with FAA to certify the system. 
Schedule 
Activity 
Commission design and construction           2017 Quarter 3 
authorization 
Design start                                       2017 Quarter 4 
Construction start                                2018 Quarter 2 
In-use date                                       2018 Quarter 4 
Cost Breakdown                                     This Request           Total Project 
Design                                                  $1,435,000             $1,455,000 
Construction                                             $3,133,000             $3,133,000 
Total                                                         $4,588,000              $4,588,000 
ALTERNATIVES AND IMPLICATIONS CONSIDERED 
Alternative 1  Status Quo 
Cost Implications: $0 
Pros: 
(1)   No cost impact 
Cons: 
(1)   Limits Sea-Tac's operational resiliency for landing aircraft 
(2)   Prevents future potential environmental benefits from being realized 
This is not the recommended alternative. 
Alternative 2  Upgrade to the basic GBAS System, as provided by Honeywell as part of the
original contract. 
Cost Implications: $3,181,000 
Pros: 
(1)   Least expensive GBAS installation alternative 

Template revised September 22, 2016; format updates October 19, 2016.

COMMISSION AGENDA  Action Item No. __6a__                              Page 4 of 5 
Meeting Date: September 12, 2017 
Cons: 
(1)   Reduced service volume (the distance from the GBAS that aircraft can receive the
signal) vs. the further upgrade in Alternative 3 
(2)   Provides limited availability in poor weather conditions 
(3)   Cannot connect to an aircraft's autopilot system.   Many airlines' flight procedures
(especially International carriers) require the pilots to utilize autopilot 
(4)   Does not take advantage of the latest GBAS technological advancements 
This is not the recommended alternative. 
Alternative 3  Install GBAS with Enhanced Features 
Cost Implications: $4,588,000 
Pros: 
(1)   This is a balanced alternative between a basic system (Alternative 2) and the yet to be
certified future system. 
(2)   Provides greater benefits over the basic system by providing increased service volume
and capability of connecting to an aircraft's autopilot system (a necessity for some
carriers) 
(3)   This alternative provides resiliency to airport operations 
Cons: 
(1)   Approximately $1 million more for the GBAS with enhanced features than the basic
GBAS upgrade that Honeywell has committed to provide 
This is the recommended alternative. 
FINANCIAL IMPLICATIONS 
Cost Estimate/Authorization Summary              Capital        Expense           Total 
COST ESTIMATE 
Original estimate                                 $3,158,000        $425,000      $3,583,000 
Current change                                   $371,000       $634,000      $1,005,000 
Revised estimate                                $3,529,000      $1,059,000      $4,588,000 
AUTHORIZATION 
Previous authorizations                             $20,000               $0         $20,000 
Current request for authorization                $3,509,000      $1,059,000      $4,568,000 
Total authorizations, including this request       $3,529,000      $1,059,000      $4,588,000 
Remaining amount to be authorized                    $0             $0             $0 


Template revised September 22, 2016; format updates October 19, 2016.

COMMISSION AGENDA  Action Item No. __6a__                              Page 5 of 5 
Meeting Date: September 12, 2017 
Annual Budget Status and Source of Funds 
GBAS (CIP#C800834) was included in the 2017-2021 capital budget and plan of finance. The
budget increase was transferred from the Aeronautical Allowance (CIP#C800753), resulting in
no net change to the capital budget. The funding source for this project will be cash (Airport
Development Fund). The airlines were briefed at the airport airline affairs committee meeting
on July 20, 2018, and a majority-in-interest (MII) vote ballot will be submitted soon. 
Financial Analysis and Summary 
Project cost for analysis              $4,568,000 
Business Unit (BU)                  Airfield Movement Area 
Effect on business performance     NOI after depreciation will increase 
(NOI after depreciation) 
IRR/NPV (if relevant)                N/A 
CPE Impact                       $0.02 increase in 2019 
Future Revenues and Expenses (Total cost of ownership) 
Port  staff  may  choose  to  outsource the on-going  maintenance  of  the  Ground  Based
Augmentation System. This would result in an estimated $110,250 per year warranty cost. If
Aviation Maintenance staff decides to maintain the system instead, there will be an upfront
training cost of approximately $132,000 or more, depending on the number of staff that needs
to be trained.  Other project expense costs include potential FAA training, Port staff technical
training, FAA flight checks, flight procedure development and associated spare parts. 
ATTACHMENTS TO THIS REQUEST 
(1)   Presentation slides 
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS 
None 






Template revised September 22, 2016; format updates October 19, 2016.