Exhaust Emissions from In-Use General Aviation Aircraft (2016)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

A I R P O R T C O O P E R A T I V E R E S E A R C H P R O G R A M ACRP RESEARCH REPORT 164 2016 Research sponsored by the Federal Aviation Administration Subscriber Categories Aviation  •  Environment Exhaust Emissions from In-Use General Aviation Aircraft Tara I. Yacovitch Zhenhong Yu Scott C. Herndon Rick Miake-Lye Aerodyne reseArch, Inc. Billerica, MA i n a s s o c i a t i o n w i t h David Liscinsky UnIted technologIes reseArch center East Hartford, CT W. Berk Knighton depArtment of chemIstry & BIochemIstry, montAnA stAte UnIversIty Bozeman, MT Mike Kenney Cristina Schoonard Paola Pringle KB envIronmentAl St. Petersburg, FL

AIRPORT COOPERATIVE RESEARCH PROGRAM Airports are vital national resources. They serve a key role in trans- portation of people and goods and in regional, national, and interna- tional commerce. They are where the nation’s aviation system connects with other modes of transportation and where federal responsibility for managing and regulating air traffic operations intersects with the role of state and local governments that own and operate most airports. Research is necessary to solve common operating problems, to adapt appropriate new technologies from other industries, and to introduce innovations into the airport industry. The Airport Cooperative Research Program (ACRP) serves as one of the principal means by which the airport industry can develop innovative near-term solutions to meet demands placed on it. The need for ACRP was identified in TRB Special Report 272: Airport Research Needs: Cooperative Solutions in 2003, based on a study spon- sored by the Federal Aviation Administration (FAA). ACRP carries out applied research on problems that are shared by airport operating agen- cies and not being adequately addressed by existing federal research programs. ACRP is modeled after the successful National Cooperative Highway Research Program (NCHRP) and Transit Cooperative Research Program (TCRP). ACRP undertakes research and other technical activi- ties in various airport subject areas, including design, construction, legal, maintenance, operations, safety, policy, planning, human resources, and administration. ACRP provides a forum where airport operators can cooperatively address common operational problems. ACRP was authorized in December 2003 as part of the Vision 100— Century of Aviation Reauthorization Act. The primary participants in the ACRP are (1) an independent governing board, the ACRP Oversight Committee (AOC), appointed by the Secretary of the U.S. Department of Transportation with representation from airport operating agencies, other stakeholders, and relevant industry organizations such as the Airports Council International-North America (ACI-NA), the American Associa- tion of Airport Executives (AAAE), the National Association of State Aviation Officials (NASAO), Airlines for America (A4A), and the Airport Consultants Council (ACC) as vital links to the airport community; (2) TRB as program manager and secretariat for the governing board; and (3) the FAA as program sponsor. In October 2005, the FAA executed a contract with the National Academy of Sciences formally initiating the program. ACRP benefits from the cooperation and participation of airport professionals, air carriers, shippers, state and local government officials, equipment and service suppliers, other airport users, and research organi- zations. Each of these participants has different interests and responsibili- ties, and each is an integral part of this cooperative research effort. Research problem statements for ACRP are solicited periodically but may be submitted to TRB by anyone at any time. It is the responsibility of the AOC to formulate the research program by identifying the highest priority projects and defining funding levels and expected products. Once selected, each ACRP project is assigned to an expert panel appointed by TRB. Panels include experienced practitioners and research specialists; heavy emphasis is placed on including airport professionals, the intended users of the research products. The panels prepare project statements (requests for proposals), select contractors, and provide technical guidance and counsel throughout the life of the project. The process for developing research problem statements and selecting research agencies has been used by TRB in managing coop- erative research programs since 1962. As in other TRB activities, ACRP project panels serve voluntarily without compensation. Primary emphasis is placed on disseminating ACRP results to the intended users of the research: airport operating agencies, service pro- viders, and academic institutions. ACRP produces a series of research reports for use by airport operators, local agencies, the FAA, and other interested parties; industry associations may arrange for workshops, training aids, field visits, webinars, and other activities to ensure that results are implemented by airport industry practitioners. ACRP RESEARCH REPORT 164 Project 02-54 ISSN 1935-9802 ISBN 978-0-309-44601-3 Library of Congress Control Number 2016956783 © 2016 National Academy of Sciences. All rights reserved. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FMCSA, FRA, FTA, Office of the Assistant Secretary for Research and Technology, PHMSA, or TDC endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. NOTICE The research report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the National Academies of Sciences, Engineering, and Medicine. The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; or the program sponsors. The Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; and the sponsors of the Airport Cooperative Research Program do not endorse products or manufacturers. Trade or manufacturers’ names appear herein solely because they are considered essential to the object of the report. Published research reports of the AIRPORT COOPERATIVE RESEARCH PROGRAM are available from Transportation Research Board Business Office 500 Fifth Street, NW Washington, DC 20001 and can be ordered through the Internet by going to http://www.national-academies.org and then searching for TRB Printed in the United States of America

The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, non- governmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president. The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. C. D. Mote, Jr., is president. The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president. The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine. Learn more about the National Academies of Sciences, Engineering, and Medicine at www.national-academies.org. The Transportation Research Board is one of seven major programs of the National Academies of Sciences, Engineering, and Medicine. The mission of the Transportation Research Board is to increase the benefits that transportation contributes to society by providing leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Board’s varied committees, task forces, and panels annually engage about 7,000 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation. Learn more about the Transportation Research Board at www.TRB.org.

C O O P E R A T I V E R E S E A R C H P R O G R A M S AUTHOR ACkNOwlEdGMENTS The measurements presented within could not have been done without the cooperation of GA airports. The authors gratefully acknowledge Stephen Bourque and the users at Boire Field, and Robert Mezzetti, A.A.E., and the Beverly Regional Airport for their support of this project and logistical assistance during engine testing. We thank Joe Sarcione for operating aircraft during early-stage engine tests and whose knowledge of engine operation helped us design a streamlined engine test matrix. We also thank the individual pilots, flight schools, fixed-base operators, charter services, and companies who provided the aircraft and experi- enced pilots for ground testing, including Mark Scott at Falcon Air, Arne Nordeide at Beverly Flight Center, Paul Beaulieu at Perception Prime Flight Instruction, and Ron Emond at Air Direct Airways, as well as Drew Gillett, Sheera Kaizerman, Brian Stoughton, and Aeroptic, LLC. CRP STAFF FOR ACRP RESEARCH REPORT 164 Christopher J. Hedges, Interim Director, Cooperative Research Programs Michael R. Salamone, ACRP Manager Marci A. Greenberger, Senior Program Officer Jeffrey Oser, Program Coordinator Eileen P. Delaney, Director of Publications Hilary Freer, Senior Editor ACRP PROJECT 02-54 PANEl Field of Environment Karen A. Scott, Tetra Tech, Louisville, KY (Chair) Patti Clark, Embry-Riddle Aeronautical University—Worldwide, Daytona Beach, FL Robert D. Freeman, Los Angeles World Airports, Los Angeles, CA Samuel J. Hartsfield, Portland, OR Corbett Smith, Mead & Hunt, Santa Rosa, CA Phillip Soucacos, Booz Allen Hamilton, Washington, DC Carl Ma, FAA Liaison Christine Gerencher, TRB Liaison

Aircraft emissions data for smaller aircraft such as piston and small turbine-powered aircraft either do not exist or have not been independently verified. The emissions data obtained as part of this project is available on the TRB website and can be added to the FAA’s AEDT database of aircraft engines so as to better understand and estimate general aviation (GA) aircraft emissions. This report provides the findings from the emissions test- ing and the data. A PowerPoint presentation provides an overview of the findings and is available on the TRB website. The FAA’s Emission and Dispersion Modeling System (EDMS) used to perform air qual- ity analysis is going to be replaced with the Aviation Environmental Design Tool (AEDT). Both modeling systems use emissions data for various aircraft engines, but there is greater confidence in the data for larger commercial aircraft engines. For smaller aircraft, such as piston and small turbine-powered aircraft, emission factor data, which is either non-existent or has not been independently verified, can result in under- or overestimating aircraft emis- sions and can make it difficult for airports with significant general aviation (GA) operations to characterize their emissions inventories. Aerodyne, as part of ACRP Project 02-54, was selected to validate existing data for GA aircraft engines, supplement the existing data, and recommend substitutions for when aircraft engine data does not exist. Their research consisted of measuring emissions from 47 engines while those engines were in use. The resulting data is available in a spreadsheet on the TRB website. Piston engine emissions were found to be extremely variable due to the flexible way in which they are operated. The effect on airports of these new emissions factors and their variability is quantified and discussed. This report, with the PowerPoint presentation, provides the information in different formats so as to be accessible to both those with a deep understanding of air quality model- ing and those needing to understand the effect at their airport. The layperson can read the italicized sections without having to read the technical mechanics, allowing any reader to better understand emissions overall. F O R E W O R D By Marci A. Greenberger Staff Officer Transportation Research Board

    1  Summary 4 Chapter 1  Background 6 Chapter 2  Research Approach 6 Pollutants in Exhaust 6 From Exhaust Pipe to Airport Emission 8 Test Procedures 11 Chapter 3  Trends in Emission Indices 11 Gas Turbine Engines 14 Piston Engines 18 GA Emission Indices Show a Great Deal of Variability 18 Quantitative Validation of Existing Data 21 Chapter 4  Sensitivity Analysis on Airport Emissions 21 Sensitivity Analysis Using EDMS/AEDT Tools 21 Introduction and Purpose 21 Assessment 21 Step 1—Identifying a Hypothetical National GA Airport Fleet 22 Step 2—Engine Matching and Substitutions 25 Step 3—Sensitivity Analysis 27 Baseline Scenario 28 Updated Scenarios 28 Results of the Sensitivity Analysis 30 Using Monte Carlo Methods to Improve Airport Emissions Estimates 36 Chapter 5  Other Parameters Affecting Emissions 36 Pilot Mindset on Fuel Mixture 37 CO2 Carbon Fraction as an Indicator of Combustion 39 Thermal NOx and Rich vs. Lean Combustion 40 Transient Emissions Are Negligible 43 Ambient Conditions 44 Fuel Additives 45 Hydrocarbon Emissions from GA Are Primarily Unburned Fuel 46 New Measures of PM to Replace “Smoke Number” 47 PM Volatility Is High for Piston Engines 48 PM Size Is Small, < 20nm, for Piston Engines 50 GA Turbofan Engines 53 Chapter 6  Conclusions 54 Future Research 55 Policy Implications of This Research C O N T E N T S

56 Appendix A  Engine Prioritization List 57 Appendix B  Test Matrix 60 Appendix C  ICAO vs. FOCA Databases 61 Appendix D  Method for Calculating Emission Ratios 64 Appendix E  Method for Calculating Emission Indices 65 Appendix F   Variability in Emissions Results from  Variability in the Engine 68 Appendix G  Gas-Phase Measurement Instruments 70 Appendix H  PM Measurement Instruments 73 Appendix I  PM Line Losses 76 Appendix J  Estimating Fuel Flows for Piston Engines 79 Appendix K  Carbon Content of AVGAS 100 LL 81 Appendix L  Hypothetical Airport Engine Mapping 85 Appendix M  Terminology and Abbreviations 87 Appendix N  References 89 Appendix O  List of Data Products 90 Appendix P  Emission Index Data Tables