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Aging of U.S. Air Force Aircraft: Final Report
Aging of U.S. Air Force Aircraft
FINAL REPORT
Committee on Aging of U.S. Air Force Aircraft
National Materials Advisory Board
Commission on Engineering and Technical Systems
National Research Council
Publication NMAB-488-2
NATIONAL ACADEMY PRESS
Washington, D.C.
1997
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Aging of U.S. Air Force Aircraft: Final Report
NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences.
The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. William A. Wulf is interim president of the National Academy of Engineering.
The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine.
The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. William A. Wulf are chairman and vice chairman, respectively, of the National Research Council.
This study by the National Materials Advisory Board was conducted under Contract No. F49620-96-C-0040 with the U.S. Air Force Office of Scientific Research. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
International Standard Book Number 0-309-05935-6
Available in limited supply from:
National Materials Advisory Board
2101 Constitution Avenue, N.W.
HA-262
Washington, DC 20418
202-334-3505
Additional copies are available for sale from:
National Academy Press
2101 Constitution Avenue, N.W. Box 285 Washington, DC 20055 800-624-6242 or 202-334-3313 (in the Washington metropolitan area)
Copyright 1997 by the National Academy of Sciences. All rights reserved.
Cover: F-15 air superior fighters. U.S. Air Force photograph.
Printed in the United States of America.
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Aging of U.S. Air Force Aircraft: Final Report
COMMITTEE ON AGING OF U.S. AIR FORCE AIRCRAFT
CHARLES F. TIFFANY (chair),
NAE, Boeing Military Airplanes (retired), Tucson, Arizona
SATYA N. ATLURI,
NAE, Georgia Institute of Technology, Atlanta
CATHERINE A. BIGELOW,
Federal Aviation Administration Technical Center, Atlantic City, New Jersey
EARL W. BRIESCH,
Dayton Aerospace Inc., Dayton, Ohio
ROBERT J. BUCCI,
Alcoa Technical Center, Alcoa Center, Pennsylvania
WENDY R. CIESLAK,
Sandia National Laboratories, Albuquerque, New Mexico
EUGENE E. COVERT, NAE,
Massachusetts Institute of Technology, Cambridge
B. BORO DJORDJEVIC,
Johns Hopkins University, Baltimore, Maryland
CHARLES E. HARRIS,
NASA Langley Research Center, Hampton, Virginia
JAMES W. MAR,
NAE, Massachusetts Institute of Technology (retired), Pacific Grove, California
J. ARTHUR MARCEAU,
Boeing Commercial Airplane Group, Seattle, Washington
CHARLES SAFF,
Boeing Information, Space, and Defense Systems Group, St. Louis, Missouri
EDGAR A. STARKE, JR.,
University of Virginia, Charlottesville
DONALD O. THOMPSON,
NAE, Iowa State University, Ames
National Materials Advisory Board Staff
THOMAS E. MUNNS, Senior Program Officer
AIDA C. NEEL, Senior Project Assistant
BONNIE SCARBOROUGH, Research Associate
National Materials Advisory Board Liaison
JAN D. ACHENBACH,
NAS/NAE, Northwestern University, Evanston, Illinois
Air Force Science and Technology Board Liaison
ALTON D. ROMIG, JR.,
Sandia National Laboratories, Albuquerque, New Mexico
Air Force Technical Liaison
JIM C.I. CHANG,
Office of Scientific Research, Washington, D.C.
WILLIAM R. ELLIOTT,
Warner-Robins Air Logistics Center, Robins AFB, Georgia
JOSEPH P. GALLAGHER,
Wright Laboratories, Wright-Patterson AFB, Ohio
JOHN W. LINCOLN,
Aeronautical Systems Center, Wright-Patterson AFB, Ohio
DONALD PAUL,
Wright Laboratories, Flight Dynamics Directorate, Wright-Patterson AFB, Ohio
VINCENT J. RUSSO,
Wright Laboratories, Materials Directorate, Wright-Patterson AFB, Ohio
O. LESTER SMITHERS,
Aeronautical Systems Center, Wright-Patterson AFB, Ohio
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Aging of U.S. Air Force Aircraft: Final Report
NATIONAL MATERIALS ADVISORY BOARD
ROBERT A. LAUDISE (chair),
NAS/NAE, Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey
G.J. ABBASCHIAN,
University of Florida, Gainesville
JAN D. ACHENBACH,
NAS/NAE, Northwestern University, Evanston, Illinois
MICHAEL I. BASKES,
Sandia/Livermore National Laboratories, Livermore, California
JESSE L. BEAUCHAMP,
NAS, California Institute of Technology, Pasadena
EDWARD C. DOWLING,
Cyprus Amax Minerals Company, Englewood, Colorado
FRANCIS DISALVO,
NAS, Cornell University, Ithaca, New York
ANTHONY G. EVANS,
NAE, Harvard University, Cambridge, Massachusetts
JOHN A.S. GREEN,
The Aluminum Association, Washington, D.C.
JOHN H. HOPPS,
Morehouse College, Atlanta, Georgia
MICHAEL JAFFE,
Hoechst Celanese Corporation, Summit, New Jersey
SYLVIA M. JOHNSON,
SRI International, Menlo Park, California
LIONEL C. KIMERLING,
Massachusetts Institute of Technology, Cambridge
HARRY A. LIPSITT,
Wright State University, Dayton, Ohio
RICHARD S. MULLER,
NAE, University of California, Berkeley
ELSA REICHMANIS,
NAE, Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey
KENNETH L. REIFSNIDER,
Virginia Polytechnic Institute and State University, Blacksburg
EDGAR A. STARKE, JR.,
University of Virginia, Charlottesville
KATHLEEN C. TAYLOR,
NAE, General Motors Corporation, Warren, Michigan
JAMES WAGNER,
Johns Hopkins University, Baltimore, Maryland
JOSEPH WIRTH,
Raychem Corporation, Menlo Park, California
BILL G.W. YEE, Pratt and Whitney,
West Palm Beach, Florida
ROBERT E. SCHAFRIK, Director
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Aging of U.S. Air Force Aircraft: Final Report
Preface
The U.S. Air Force requested the National Research Council to identify research and development (R&D) needs and opportunities to support the continued operation of their aging aircraft. Specifically, this study focuses on aging aircraft structures and materials and has the major objectives of
developing an overall strategy that addresses the Air Force aging aircraft needs
recommending and prioritizing specific technology opportunities in the areas of
fatigue, corrosion fatigue, and stress corrosion cracking
corrosion prevention and mitigation
nondestructive inspection
maintenance and repair
failure analysis and life prediction methodologies
The approach that the committee took to accomplish this study was to conduct working sessions to identify current aging aircraft problems and technology needs; review ongoing and planned aging aircraft R&D efforts by the Air Force; and review related research at other government agencies, within industry, and in the academic research community.
The committee conducted a total of six meetings, prepared an interim report (NMAB-488-1), which was released in March 1997, and prepared this final report. In addition, numerous data-gathering discussions were held between individual committee members and various individuals from within the Air Force's research, engineering, logistics, and operational organizations. The purpose of the first meeting held at the Wright Aeronautical Laboratories, Wright-Patterson AFB, Ohio, was to review current and planned laboratory programs that are part of the Air Force aging aircraft program. The purpose of the second meeting, held at the San Antonio Air Logistics Center, Kelly AFB, Texas, was to identify the common problems associated with maintaining and operating aging systems and to review the applied R&D efforts under way at the Air Force air logistic centers (ALCs). Representatives from the five ALCs (i.e., Warner-Robins, Oklahoma City, San Antonio, Ogden, and Sacramento) participated in the meeting. At the third committee meeting, held in Washington, D.C., the committee reviewed ongoing and recently completed basic research programs at the Air Force Office of Scientific Research and developed the preliminary findings for the interim report. The fourth meeting was held in Irvine, California, at which time the committee reviewed related research being conducted by the National Aeronautics and Space Administration and the Federal Aviation Administration, finalized the interim report, and began developing recommendations for an overall aging aircraft strategy and identifying future research opportunities. At the fifth meeting, which was held in Washington, D.C., the committee reviewed related research being conducted by the Navy and received briefings on the F-15 aircraft structural history and on the aging of advanced composite structures. In addition, the committee continued their discussions on recommended strategy, research opportunities, and an approach for the prioritization of these opportunities. The sixth and final committee meeting was held in Washington, D.C., for the purpose of finalizing the prioritization of research opportunities and reviewing the initial draft of this final report.
The interim report that was released in March 1997 was prepared at the request of the Air Force research community and included the committee's preliminary technical assessment of the Air Force current aging aircraft R&D program. The report provided a description of the Air Force's aging aircraft problem from the force management perspective, a preliminary assessment of the force management process and its needs, a discussion of the key technical issues and apparent R&D needs, and a preliminary assessment of the current aging aircraft R&D program along with suggested areas of improvement and changes in emphasis.
As was pointed out in the preface to the committee's interim report, it became apparent very early in this study that the overall strategy to address the Air Force's aging aircraft needs must encompass much more than R&D needs and opportunities. There are a number of overarching engineering and management issues that also need to be addressed. These include issues involving the force management process, the continued enforcement of the Air Force's Aircraft Structural Integrity Program and its supporting structures and materials specifications, the need to update the durability and damage tolerance assessments of the aging aircraft, the need for increased emphasis on identifying and applying existing technologies to the Air Force's aging aircraft problems, the need for stable funding for technology transition at the Air Force's ALCs, and the technical skills needed to support the aging aircraft program. This final report presents an overall strategy that the committee believes addresses these issues as well as the near-term and long-term research and development needs and opportunities.
Charles F. Tiffany, Chair
Committee on Aging of U.S. Air Force Aircraft
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Aging of U.S. Air Force Aircraft: Final Report
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Aging of U.S. Air Force Aircraft: Final Report
Contents
EXECUTIVE SUMMARY
1
PART I
PROBLEM DEFINITION AND STATUS OF THE AGING FORCE
9
1
INTRODUCTION
11
Background,
11
Study Objectives,
11
2
AGING AIRCRAFT PROBLEM
13
Managing the Force Structure,
13
Future Force Projections,
16
Assessment of the Force Structural Management Process,
19
3
CURRENT STRUCTURAL STATUS OF THE AGING FORCE
22
Air Force-Supported Aircraft,
22
Contractor Logistics-Supported Aircraft,
24
4
TECHNICAL ISSUES AND OPERATIONAL NEEDS
27
Corrosion,
27
Stress Corrosion Cracking,
28
Fatigue Cracking,
29
Nondestructive Evaluation,
32
Structural Maintenance and Repairs,
33
PART II
RECOMMENDED STRATEGY AND OPPORTUNITIES FOR NEAR-TERM AND LONG-TERM RESEARCH
35
5
ENGINEERING AND MANAGEMENT TASKS
39
Update of Durability and Damage Tolerance Assessments,
39
Update of Force Structural Maintenance Plans and Individual Aircraft Tracking Programs,
41
Stress Corrosion Cracking Assessments,
42
Improved Corrosion Control Programs,
43
Economic Service Life Estimation,
45
Continued Enforcement of the Aircraft Structural Integrity Program,
46
Technical Oversight and Retention of Technical Capabilities,
47
Technology Transition into Aging Aircraft,
48
6
RESEARCH RECOMMENDATIONS: FATIGUE
49
Low-Cycle Fatigue,
49
High-Cycle Fatigue,
51
Corrosion/Environmental Effects,
54
7
RESEARCH RECOMMENDATIONS: CORROSION AND STRESS CORROSION CRACKING
57
Corrosion Prevention and Control,
57
Stress Corrosion Cracking,
60
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Aging of U.S. Air Force Aircraft: Final Report
8
RESEARCH RECOMMENDATIONS: NONDESTRUCTIVE EVALUATION AND MAINTENANCE TECHNOLOGY
63
Nondestructive Evaluation,
63
Maintenance and Repair,
68
9
PRIORITIZED RESEARCH RECOMMENDATIONS
73
Critical Priorities,
73
Near-Term Research,
73
Long-Term Research,
74
10
FUTURE STRUCTURAL ISSUES: COMPOSITE PRIMARY STRUCTURES
76
Applications and Service Experience,
76
Recommendations for Long-Term Research,
77
REFERENCES
79
APPENDICES
A
SYNOPSES OF AIR FORCE AGING AIRCRAFT STRUCTURAL HISTORIES
87
B
BIOGRAPHICAL SKETCHES OF COMMITTEE MEMBERS
111
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Aging of U.S. Air Force Aircraft: Final Report
Tables and Figures
TABLES
ES-1
Priority-1 Near-Term and Long-Term-Research Recommendations
5
ES-2
Priority-2 Near-Term and Long-Term Research Recommendations
6
ES-3
Priority-3 Near-Term and Long-Term Research Recommendations
7
2-1
Tasks of the Air Force Aircraft Structural Integrity Program
15
3-1
Data on Force Status for Air Force-Supported Aircraft
23
3-2
Air Force Commercial-Derivative Aircraft Using Contractor Logistics Support
24
3-3
Comparison between Utilization of Air Force CLS Aircraft and Commercial Equivalents
25
5-1
Prioritization of DADTA Update Needs for Air Force-Supported Aircraft
40
8-1
Critical NDE Inspection Needs for Aging Aircraft
65
9-1
Prioritized Near-Term Research Recommendations
74
9-2
Prioritized Long-Term Research Recommendations
75
FIGURES
2-1
Force structure projection for the ACC fighter, bomber, and attack aircraft
17
2-2
Force structure projection for the ACC airlift and rescue aircraft
17
2-3
Force structure projection for other ACC aircraft
18
2-4
Force structure projection for AMC aircraft
18
2-5
Force structure projection for AFSOC aircraft
19
2-6
Force structure projection for AETC aircraft
20
II-1
Recommended overall strategy to address Air Force aging aircraft challenges
36
II-2
Basic elements of the recommended near-term and long-term R&D programs
37
5-1
Overall approach to durability and damage tolerance assessments
40
5-2
Organization of commercial aircraft industry aging aircraft working groups
44
A-1
C-5 flying hour distribution
90
A-2
General locations for B-52G/H structural improvements
92
A-3
B-52H current use rate
93
A-4
F-15 buffet-induced problems
96
A-5
F-16 structural arrangement
97
A-6
F-16 structural modification areas
98
A-7
A-10 structural arrangement
99
A-8
Boeing 707 wing tear-down locations
102
A-9
F-111 D6ac steel components
105
A-10
Original lower wing skin design for the T-38 aircraft
109
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Aging of U.S. Air Force Aircraft: Final Report
Acronyms
AATSG
aging aircraft technical steering group
AAWG
Airworthiness Assurance Working Group
ACC
Air Combat Command
ACI
analytical condition inspection
AETC
Air Education and Training Command
AFMPP
Air Force modernization planning process
AFR
Air Force regulation
AFSOC
Air Force Special Operations Command
ALC
air logistics center
AMC
Air Mobility Command
ASIP
Aircraft Structural Integrity Program
CACRC
Commercial Aircraft Composite Repair Committee
CLS
contractor logistics support
CPC
corrosion-preventive compound
CPCP
corrosion prevention and control program
DADTA
durability and damage tolerance assessment
EIF
equivalent initial flaw
FAA
Federal Aviation Administration
FAR
Federal Air Regulation
FSMP
force structural maintenance plan
IATP
individual aircraft tracking program
JPATS
Joint Primary Aircraft Training System
JSF
Joint Strike Fighter
LESS
loads/environment spectra study
LIF
lead-in fighter
NASA
National Aeronautics and Space Administration
NDE
nondestructive evaluation
NDI
nondestructive inspection
PDM
programmed depot maintenance
POD
probability of detection
R&D
research and development
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Aging of U.S. Air Force Aircraft: Final Report
SAB
Scientific Advisory Board
SCC
stress corrosion cracking
TIE
Technology and Industrial Support Engineering (ALC)
TPIPT
technology planning integrated product team
VOC
volatile organic compound
WFD
widespread fatigue damage
