Evaluation of the Transport Airplane
Risk Assessment Methodology
Committee on Transport Airplane Risk Assessment Methodology
Aeronautics and Space Engineering Board
Division on Engineering and Physical Sciences
A Consensus Study Report of
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This activity was supported by Contract 693KA9-21-T-00009 with the Federal Aviation Administration. Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any agency or organization that provided support for the project.
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Digital Object Identifier: https://doi.org/10.17226/26519
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Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2022. Evaluation of the Transport Airplane Risk Assessment Methodology. Washington, DC: The National Academies Press. https://doi.org/10.17226/26519.
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COMMITTEE ON TRANSPORT AIRPLANE RISK ASSESSMENT METHODOLOGY
GEORGE T. LIGLER, NAE,1 GTL Associates and Texas A&M University, Chair
ERIC ALLISON, Joby Aviation
JOHN-PAUL B. CLARKE, The University of Texas at Austin
LETICIA CUELLAR-HENGARTNER, Los Alamos National Laboratory
KAREN M. FEIGH, Georgia Institute of Technology
JEFF GUZZETTI, Guzzetti Aviation Risk Discovery, LLC
RONALD J. HINDERBERGER, The Boeing Company (retired)
ZAHRA MOHAGHEGH, University of Illinois at Urbana-Champaign
PAUL MORELL, American Airlines (retired)
JAN C. SCHILLING, NAE, General Electric Aviation (retired)
ROBERT E. VOROS, Merlin Labs, LLC
AMIR YACOBY, NAS,2 Harvard University
Staff
ARUL MOZHI, Senior Program Officer
LINDA WALKER, Program Coordinator
ALAN ANGLEMAN, Associate Director, Space Studies Board and Aeronautics and Space Engineering Board, Study Director
COLLEEN N. HARTMAN, Director, Space Studies Board, Aeronautics and Space Engineering Board, and Board on Physics and Astronomy
___________________
1 Member, National Academy of Engineering.
2 Member, National Academy of Sciences.
AERONAUTICS AND SPACE ENGINEERING BOARD
ILAN KROO, NAE,1 Stanford University, Chair
BRIAN M. ARGROW, NAE, University of Colorado Boulder
ROBERT D. BRAUN, NAE, NASA Jet Propulsion Laboratory
EDWARD F. CRAWLEY, NAE, Massachusetts Institute of Technology
WILLIAM R. GRAY III, United States Air Force
SUSAN J. HELMS, NAE, Orbital Visions, LLC
JOHN C. KARAS, Lockheed Martin Space Systems Company
ANDREW R. LACHER, Noblis
NICHOLAS D. LAPPOS, NAE, Sikorsky, a Lockheed Martin Company
GEORGE T. LIGLER, NAE, GTL Associates
LESTER L. LYLES, NAE, United States Air Force
VALERIE MANNING, Airbus
PARVIZ MOIN, NAE/NAS,2 Stanford University
DARRYLL J. PINES, NAE, University of Maryland
ROBIE I. SAMANTA ROY, Electra.aero
WANDA A. SIGUR, NAE, Independent Consultant
DAVID W. THOMPSON, NAE, Orbital ATK, Inc.
ANTHONY M. WAAS, University of Michigan
MICHAEL I. YARYMOVYCH, NAE, Sarasota Space Associates
SHERRIE L. ZACHARIUS, Aerospace Corporation
Staff
COLLEEN N. HARTMAN, Director
ALAN ANGLEMAN, Associate Director
DWAYNE DAY, Senior Program Officer
MARGARET A. KNEMEYER, Financial Officer
RADAKA LIGHTFOOT, Senior Financial Associate
ARUL MOZHI, Senior Program Officer
DANIEL NAGASAWA, Program Officer
CELESTE A. NAYLOR, Information Management Associate
TANJA PILZAK, Manager, Program Operations
ANDREA REBHOLZ, Program Coordinator
___________________
1 Member, National Academy of Engineering.
2 Member, National Academy of Sciences.
Acknowledgment of Reviewers
This Consensus Study Report was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise. The purpose of this independent review is to provide candid and critical comments that will assist the National Academies of Sciences, Engineering, and Medicine in making each published report as sound as possible and to ensure that it meets the institutional standards for quality, objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process.
We thank the following individuals for their review of this report:
Although the reviewers listed above provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations of this report nor did they see the final draft before its release. The review of this report was overseen by John J. Tracy, NAE, The Boeing Company (retired), and Roger L. McCarthy, NAE, McCarthy Engineering. They were responsible for making certain that an independent examination of this report was carried out in accordance with the standards of the National Academies and that all review comments were carefully considered. Responsibility for the final content rests entirely with the authoring committee and the National Academies.
___________________
1 Member, National Academy of Sciences.
2 Member, National Academy of Engineering.
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Preface
The origin of this study is a mandate contained within the Aircraft Certification, Safety, and Accountability Act,1 signed into law on December 27, 2020. In accordance with this Act, the Federal Aviation Administration (FAA) entered into a contract with the National Academies of Sciences, Engineering, and Medicine (the National Academies) to conduct a study to assess the Transport Airplane Risk Assessment Methodology (TARAM) process used by the FAA.
This report responds to the statement of task specified in the Aircraft Certification, Safety, and Accountability Act. It must be noted at the outset that this report does not assess the application of the TARAM process to any specific incidents or accidents, including the 737 MAX accidents. While the committee was provided a copy of the 737 MAX TARAM analysis provided by the FAA to Congress in late 2019, FAA management declined to provide additional details or to discuss the TARAM analysis of the 737 MAX with the committee. The committee, therefore, was unable to comment on the 737 MAX TARAM analysis. Regardless, the committee was able to make recommendations that, if adopted, would significantly improve the TARAM process.
The study statement of task is as follows:
The National Academies of Sciences, Engineering, and Medicine (National Academies) shall appoint an ad hoc committee to undertake a study that will assess the Transport Airplane Risk Assessment Methodology (TARAM) process used by the Federal Aviation Administration. The study will:
- Review the role and objectives of TARAM within the FAA’s overall safety oversight system,
- Assess the TARAM analysis process,
- Assess the effectiveness of the TARAM for the purposes of improving aviation safety, and
- Provide recommendations to improve the methodology and effectiveness of the TARAM as an element of aviation safety.
This statement of task requires a deep understanding of the TARAM process, its usage, what inputs TARAM needs, the source of these inputs, and who executes the TARAM process. From the TARAM analysis prediction to incorporating TARAM results into the FAA’s continued operational safety (COS) decision-making process, the overall TARAM process was studied.
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1 This Act is part of the Consolidated Appropriations Act, 2021, included in it as DIVISION V—Aircraft Certification, Safety, and Accountability.
To understand the study origin and context, the committee heard from the congressional committee staff. To understand the TARAM analysis process and how it is used in support of aircraft COS, the committee held informational reviews with the FAA leadership team. These were followed by informational reviews with key FAA technical experts responsible for the formulation of the TARAM process. To understand how the Aircraft Certification Offices (ACOs) use the TARAM process, the committee received a briefing on the Seattle ACO Transport Airplane Safety Manual and examples of its use. To further assess whether parameters within the TARAM analysis process are similar with other industry or federal agency processes that deal with safety concerns, the committee received presentations from the National Aeronautics and Space Administration and from the U.S. Nuclear Regulatory Commission on how risk analysis is used for decision-making.
The committee also independently reviewed the FAA’s Policy Statement PS-ANM-25-05 Risk Assessment Methodology for Transport Category Airplanes dated November 4, 2011, referencing Safety Management System, the FAA’s Aircraft Certification Service Order 8110.107A Monitor Safety/Analyze Data dated October 1, 2012, the FAA’s Transport Airplane Risk Assessment Methodology (TARAM) Handbook dated November 4, 2011, and Seattle ACO’s Transport Airplane Safety Manual, released September 1, 2021. This was completed to understand not only the defined ownership for TARAM analysis and its details but also the FAA’s role in assessing unsafe conditions.
George T. Ligler, Chair
Committee on Transport Airplane Risk Assessment Methodology
Contents
Use of the TARAM Results in COS Decision-Making
3 ROLE OF TARAM WITHIN THE FAA’S OVERALL SAFETY OVERSIGHT SYSTEM
TARAM and MSAD in the Context of Safety Oversight
TARAM in the Context of Rulemaking
TARAM in the Context of Type Certification
4 IMPROVEMENTS FOR THE INPUT DATA TO TARAM
Improving Completeness, Accessibility, and Quality of Input Data to TARAM
Characterizing Uncertainty in Input Data to TARAM
5 IMPROVEMENTS TO THE TARAM PROCESS
Improving Systematic Risk Modeling in the TARAM Process
Incorporating Human Reliability Analysis in the TARAM Process
Incorporating Software Reliability Analysis in the TARAM Process
6 IMPROVEMENTS FOR THE USE OF TARAM OUTPUTS
Improving Uncertainty Consideration in TARAM Decision-Making Guidance
Incorporating Risk Importance Ranking in TARAM Decision-Making Guidance
Improving the Quality of the COS Decision-Making Process When Using the TARAM Results
A Current TARAM Process Details