wled the Web.
The web site itself may have changed. You can check the current page or check for previous versions at the Internet Archive. Yahoo! is not affiliated with the authors of this page or responsible for its content.
REDUCED DENSITY AIRPORT LIGHTING SYSTEM EVALUATION
Modification of Visual Approach
Slope Indicator Baffles at Pearson Field
Airpark, Vancouver, WA








James W. Patterson, Jr.










June 2007

DOT/FAA/AR-TN07/12



This document is available to the public through the National
Technical Information Service (NTIS), Springfield Virginia 22161










U.S. Department of Transportation
Federal Aviation Administration


o
te technical note technic
a

NOTICE

This document is disseminated under the sponsorship of the U.S.
Department of Transportation in the interest of information exchange. The
United States Government assumes no liability for the contents or use
thereof. The United States Government does not endorse products or
manufacturers. Trade or manufacturer's names appear herein solely
because they are considered essential to the objective of this report. This
document does not constitute FAA certification policy. Consult your local
airports office as to its use.




























This report is available at the Federal Aviation Administration William J.
Hughes Technical Center's Full-Text Technical Reports page:

actlibrary.tc.faa.gov in Adobe Acrobat portable document format (PDF).








Technical Report Documentation Page
1. Report No.


DOT/FAA/AR-TN07/12
2. Government Accession No.

3. Recipient's Catalog No.

4. Title and Subtitle
MODIFICATION OF VISUAL APPROACH SLOPE INDICATOR
BAFFLES AT PEARSON FIELD AIRPARK, VANCOUVER, WA
5. Report Date

June 2007


6. Performing Organization Code

AJP-6311

7. Author(s)

James W. Patterson, Jr.
8. Performing Organization Report No.

9. Performing Organization Name and Address

Federal Aviation Administration
William J. Hughes Technical Center
Airport and Aircraft Safety Research and Development Division
Airport Technology Research and Development Branch
10. Work Unit No. (TRAIS)

Atlantic City International Airport, NJ 08405

11. Contract or Grant No.



12. Sponsoring Agency Name and Address

U.S. Department of Transportation
Federal Aviation Administration
Operations Engineering Group, Infrastructure Support Center-Seattle
FAA Northwest Mountain Regional Office
1601 Lind Ave, SW
13. Type of Report and Period Covered

Technical Note
Renton, WA 98057
14. Sponsoring Agency Code

AJW-W23
15. Supplementary Notes

Paul Jones of AJP-6311, Jim Newman and Nelson Brown of Hi-Tec Systems, Stacey Campbell of the FAA Portland Terminal
System Support Center, and lead civil engineer Thinh Vu of the FAA Northwest-Mountain Region provided support throughout
the course of the evaluation.
16. Abstract

This technical note describes a research effort that was accomplished to correct a safety deficiency with a Visual Approach Slope
Indicator (VASI) system at the Pearson Field Airpark in Vancouver, Washington. During a recent inspection flight, the VASI
system was found to be emitting signals that could potentially draw an approaching aircraft dangerously close to an obstruction
near the final approach path. As a result, the system was shutdown. The VASI system had baffles previously installed on the
inside and on the front opening of the unit that were intended to limit the emission of light in the direction of the obstruction. The
baffles were found to have very comparable opening widths in all units of the system, which allowed the signal from some units
to be visible within a very close proximity to an obstruction. Typically, each opening requires a different width to provide proper
signal blocking at the specific location of the obstruction. The Federal Aviation Administration Northwest-Mountain Region,
Navigational Surveillance Weather Systems Team requested the Airport Technology Research and Development Branchs
assistance in correcting the misaligned baffles so that the VASI system could be restored to operation.

Engineers from the Airport Technology Research and Development Branch visited the site to analyze the problem; collect data on
the geometry of the obstruction, the baffles, and the general layout of the airport; and install and test the new baffles to make sure
they operate properly. Engineers designed, constructed, and installed aluminum baffles that blocked the signal from the
obstruction area, and provided a 2 degree margin of safety between the obstruction and the visible signal of the VASI.

Ground and flight evaluations conducted by the Airport Technology Research and Development Branch verified that the installed
baffles had eliminated the hazard by preventing a usable VASI signal from being seen near the obstruction.

17. Key Words
Visual Approach Slope Indicator, Baffles, Baffling, Visual
Aid, Pearson Field Airpark, Vancouver, Portland
18. Distribution Statement
This document is available to the public through the National
Technical Information Service (NTIS), Springfield, Virginia
22161.
19. Security Classif. (of this report)

Unclassified
20. Security Classif. (of this page)

Unclassified
21. No. of Pages


24
22. Price

Form DOT F 1700.7
(8-72)

Reproduction of completed page authorized
TABLE OF CONTENTS

Page

EXECUTIVE SUMMARY

vii
INTRODUCTION
1

Purpose

1
Background
1

Scope

2

Objectives

2

Related
Documents

3
DISCUSSION
3
EVALUATION APPROACH

6


Required
Equipment

6

Method

6

Evaluation
Process

8

RESULTS
8

CONCLUSIONS

9
APPENDICES

AFigures Indicating VASI Unit Measurements
BPhotographs of the Site and Final Modification

iii
LIST OF FIGURES

Figure
Page

1
Diagram of VASI Unit Closer to Runway 8 Threshold
5
2
Diagram of VASI Unit Further From Runway 8 Threshold
5

iv
LIST OF TABLES

Table
Page

1
Angles Measured From VASI Centerline to Indicated Line
6
v
vi
LIST OF ACRONYMS

FAA
Federal Aviation Administration
mi Mile
OR
Oregon
SCC
System support center
VASI
Visual approach slope indicator
VUO
Pearson Field Airpark
WA Washington
EXECUTIVE SUMMARY


This technical note describes a research effort that was accomplished to correct a safety
deficiency with a Visual Approach Slope Indicator (VASI) system at the Pearson Field Airpark
in Vancouver, Washington. During a recent inspection flight, the VASI units were found to be
emitting a usable signal that could potentially draw an approaching aircraft dangerously close to
an obstruction near the final approach path. As a result, the VASI system was shutdown. The
VASI system had baffles previously installed on the inside and on the front opening of the unit
that were intended to limit the emission of light in the direction of the obstruction. The baffles
but were found to have very comparable opening widths in all units of the system, which allowed
the signal from some units to be visible within a very close proximity to an obstruction.
Typically, each opening requires a different width to provide proper signal blocking at the
specific location of the obstruction. The Northwest-Mountain Region, Navigational Surveillance
Weather Systems Team, AJW-W23, requested the Airport Technology Research and
Development Branchs assistance in correcting the misaligned baffles so that the VASI system
could be restored to operation.

Engineers from the Airport Technology Research and Development Branch visited the site to
analyze the problem; collect data on the geometry of the obstruction, the baffles, and the general
layout of the airport; and finally install and test the new baffles to make sure they operate
properly. Engineers designed, constructed, and installed aluminum baffles that blocked the
signal from the obstruction area, and provided a 2 degree margin of safety between the
obstruction and the visible signal of the VASI.

Ground and flight evaluations conducted by the Airport Technology Research and Development
Branch verified that the installed baffles had eliminated the hazard by preventing usable VASI
signals from being visible near the obstruction.
vii/viii
INTRODUCTION

PURPOSE.

The effort described in this technical note was accomplished in response to a request for
assistance received from the Federal Aviation Administration (FAA) Northwest Mountain
Region Navigational Surveillance Weather Systems Team, AJW-W23, to assist the Portland,
Oregon (OR) FAA System Support Center (SSC).