By: Robert E. Ball


In 1967, I, at age 32 (and with no military service or aircraft background other than an early fascination with the aircraft fighting in World War II), joined the faculty of the Department of Aeronautics at the Naval Postgraduate School (NPS), in Monterey, CA, as an Assistant Professor. My credentials were a B.S. (1958), M.S. (1959), and Ph.D. (1962) in structural engineering from Northwestern University; 5 years spent with two small engineering consulting firms near Pasadena, CA; and the development of a major NASA-Langley-funded digital computer program—known as SATANS—that computed the geometrically nonlinear static and dynamic response of arbitrarily loaded shells of revolution (which was applicable to the Apollo space capsule during reentry). I was hired to teach 30–35-year-old military aviators how aircraft structures are analyzed and designed so that these aviators would be better aircraft program managers later in their military careers.

Then, in 1971 the Department of Defense (DoD) Joint Aeronautical Commanders established the tri-Service Joint Technical Coordinating Group on Aircraft Survivability (JTCG/AS). The JTCG/AS was established largely because of the relatively high number of fixed- and rotary-wing U.S. aircraft— approximately 4,100 from all three Services—that had been lost to enemy fire in the 1964–1973 Southeast Asia (SEA) conflict. Many, if not most, of these aircraft had not been designed to survive in the type of man-made hostile environment they ultimately encountered. As a consequence of these heavy losses, one of the major goals assigned to the JTCG/AS was to establish ACS as a new design discipline for U.S. military aircraft so that new (or modified) U.S. aircraft would have a much better probability of surviving future conflicts than their predecessors had in past conflicts.

A few years after the JTCG/AS was established, the organization offered to fund me to develop a computer program for the dynamic structural response of the fuel tanks on the B-1 bomber when hit by a bullet or warhead fragment. The penetration of the bullet or fragment through the contained fuel causes a large transient fluid pressure on the walls of the tank, known as hydraulic (then) and hydrodynamic (now) ram.

It was then that I learned about the goals of the JTCG/AS, particularly the goal to establish ACS as a design discipline for aircraft. To me, as a structures engineering teacher who learned how to analyze and design structures at Northwestern, the JTCG/AS design discipline goal created the need for the development of a new formal ACS educational program that would teach those who may affect the survivability of U.S. military aircraft the fundamentals of this new design discipline. It was evident that this discipline needed to be similar to the existing aircraft design disciplines, such as structures, fuel systems, flight controls, aerodynamics, and propulsion, each with its common terminology, metric assessment methodology, design technology, and a set of requirements validated by testing. It should be broad in concept and coverage, and it must become an integral part of system engineering for military aircraft because it can have a major impact on all of the other aircraft design disciplines (e.g., rugged structures; significantly more fire/explosion/leak protection for fuel systems; redundant and separated self-repairing flight controls; highly maneuverable, agile, and stealthy aerodynamic shapes; and stealthy propulsion), as well as the operational tactics of military aircraft.

So where should this new discipline be developed and taught? This question of location was significant because, in the mid-1970s, military subjects, such as combat survivability, were not particularly popular at most U.S. schools, colleges, and universities. And the answer that I came up with was none other than the NPS Department of Aeronautics. Because many NPS graduates are eventually assigned to work in, and often lead, the engineering offices involved in the development of U.S. military aircraft, they will have an opportunity to influence an aircraft’s design for survivability. Furthermore, NPS has a vested interest in establishing and operating a course whose intent is to enhance the survival of military pilots. (And, incidentally, what exceptional students the NPS Department of Aeronautics has had. Eighteen of the students in my courses eventually became NASA astronauts, and one, VADM David Dunaway [an ACS thesis student of mine], became Commander of NAVAIR. Several others reached flag rank, and many led major DoD/Service offices.)

So, I approached the department chair and asked if it was okay if I started a new elective course in aircraft combat survivability. He asked, “What is that?” After I made a presentation to the department faculty on what ACS was all about, I was given the okay to proceed.

I next approached the first head of the Naval Air System’s Command’s (NAVAIR’s) recently established Survivability Division, CAPT Wendy Rivers, and his right-hand man, Dale Atkinson, with my proposal to develop and teach the fundamentals of ACS at NPS. CAPT Rivers, Dale, and the JTCG/AS leadership all agreed that the course should be developed and taught at NPS.

Consequently, around 1975, I started the development of the unclassified (but distribution-limited) NPS graduate-level course entitled Aircraft Combat Survivability (AE3251), which I believe was the first formal course in ACS in existence (see Figure 1). My first action item was to get some help, and quickly. I coerced two Navy aviator students, Robert Nosco (an A-7 pilot) and Karl Krumbholz (a P-3 pilot), into working with me as M.S. thesis students. We then began a search for available material to use in our development and presentation of the ACS fundamentals. This search was complicated, however, by the fact that much of the previous work in ACS was classified. In addition, although much of the ACS terminology at the time was common between the three Services, there were differences that needed to be addressed if ACS was to become a design discipline for all Services. As with any design discipline, a common terminology is essential.

Figure 1. An ACS Course Being Taught at NPS.

Fortunately, the two most important ACS fundamentals for surviving a man-made hostile environment had already been established. Namely, an aircraft can survive in combat if it can:

  • Avoid being “hit” by any damage (causing) mechanisms associated with the enemy’s weapons (e.g., bullets, warhead fragments, blast waves, and incendiaries)
  • Withstand any “hit(s)” by the damage mechanisms that do occur.

Likewise, the two existing terms associated with these two fundamentals were:

  • Susceptibility – the inability to avoid being “hit” by a damage mechanism.
  • Vulnerability – the inability to withstand any “hit(s)” that do occur.

Bob concentrated on susceptibility, Karl took on vulnerability, and I began developing the unclassified course notes to be handed out to the students. The first offering of AE3251 was in the fall of 1977. Twenty-six curious military aviators—many of whom had been shot at (and some even shot down) in the SEA conflict—arrived wondering what this new course was all about. The students seemed to like it, fortunately, and they ended up teaching me more than I taught them about military aircraft and surviving in combat. The course quickly became a biannual course (and a required course for students in the Aeronautical Engineering [Avionics] curriculum), and it has been taught at the NPS twice a year for nearly all of the past 40 years.

In early 1978, shortly after the initial presentation of AE3251, Dale Atkinson suggested that he, John Morrow (from the Naval Weapons Center in China Lake, CA), and I develop a JTCG/AS-sponsored short course on ACS that was based upon AE3251, but with considerable presentation participation by others within the ACS community. In the late spring of 1978, the first short course was held in a packed auditorium at the NAVAIR Headquarters in Washington, DC, and a second short course was presented at NPS a few months later.

At least one short course per year then followed for most of the next 40 years at NPS and other pertinent DoD and Service locations. A typical 5-day short course at NPS in the mid-1990s was held in an auditorium filled with approximately 150 U.S. attendees from both industry and the DoD/military. One particularly notable short course presenter was Dave Hall of the Naval Air Warfare Center in China Lake, CA, who for many years presented the “How to Do a Survivability Assessment” lectures on the final day of the course.

In 1982, CAPT Chuck Cromer, the head of NAVAIR’s on-site office at McDonnell Aircraft Company in St. Louis, MO (and my one and only Ph.D. [structures] student), invited me to give a personal ACS short course presentation that was similar to the presentations I had been making for NPS and the JTCG/AS. He wanted to directly expose the engineers and managers at McDonnell to the ACS fundamentals I had been developing. I accepted the invitation, knowing that the presentation would give me an opportunity to talk directly to those who can impact the survivability design of McDonnell aircraft. I also knew that I would learn from them as well. Soon after, other military aircraft and engine companies wanted similar presentations. So, over the next 18 years, I presented approximately 40 of these on-site, 5-day, 20-hour short courses at nearly all of the major military aircraft and engine companies (with most companies requesting more than one presentation).

As the years passed, the course notes grew in size and content, and by 1985, they were published under my authorship as a 400-page textbook titled The Fundamentals of Aircraft Combat Survivability Analysis and Design in the relatively new American Institute of Aeronautics and Astronautics (AIAA) Education Series (see Figure 2). Approximately 10,000 copies of the textbook were sold between 1985 and 2003.

Figure 2. First Edition of the ACS Textbook.

In 1986, the JTCG/AS also funded development and production of a 50-minute (distribution-limited) video titled “Threat Effects in Aircraft Combat Survivability.” The video, which was produced by Robert E. Ball, Jr. (with the SURVICE Engineering Company), contains unique combat and gun-camera footage, as well as lethality and survivability test analysis video, demonstrating the effects of threats on combat aircraft. The video has undergone several updates over the past 30+ years. (Authorized readers can obtain a copy of the current version from the Defense Systems Information Analysis Center [DSIAC] by sending an email to

In 1989, I introduced the first Surface Ship Survivability (ME3950) course for the Department of Mechanical Engineering (ME) at NPS. The course, which was developed at the request of several individuals within the surface ship survivability community, was based upon the fundamentals for ACS. A few years later, the course materials were transferred to a new ship design sequence of ME courses introduced by Prof. Charles Calvano, and ME3950 was removed from the ME course catalog. (For more information on the surface ship survivability design discipline, readers are referred to a Naval Engineers Journal article by Ball and Calvano [1994], which can be accessed at doi/10.1111/j.1559-3584.1994.tb02798.x/ abstract.)

In 1994, AE3251 was the first NPS course taught as part of the new NPS Distance/Distributed Learning Program, in which off-campus DoD employees could earn an M.S. degree. The program used live video teleconferencing (VTC) to connect one or more distant sites with the live class at NPS. The first site chosen was the NAVAIR Headquarters in Washington, DC, with several more military sites, including the Air Force Materiel Command and the Army Aviation and Troop Command, eventually included. Also, for many years, non-NPS students could take AE3251 for NPS graduate-level credit as a correspondence course using specially prepared self-study materials and the AIAA ACS textbook.

In 2000, I retired from teaching ACS both at NPS and the JTCG/AS short course to concentrate on writing and eventually publishing (in 2003) the 900-page second edition of the AIAA textbook (see Figure 3). Approximately 6,300 hard copies (with attached CDs) and 2,300 CD-only copies have been sold so far. In addition, a few years later, in 2007, the book was selected for the AIAA Summerfield Book Award, named in honor of Martin Summerfield, founder and initial editor of AIAA’s Progress in Astronautics and Aeronautics book series. (Note that Government employees can obtain a copy of the AIAA textbook from DSIAC at, and others can purchase a copy from AIAA or most bookstores.)

Figure 3. Second Edition of the ACS Textbook.


Although the development of an ACS educational program at NPS may appear to be seamless, it was not all smooth-going after 2000. Some major help was needed along the way, and most of that help was provided (first) by Mark Couch and (later) Christopher Adams.

When I left NPS and teaching to finish the second edition of the textbook, someone was needed to take over the NPS and JTCG/AS courses. Mark Couch was that someone. He was a Navy MH-53E pilot who had taken my NPS course in the early 1990s when he was an M.S. graduate student in the NPS Aeronautical Engineering program. In 1999, Mark was assigned to the Navy’s military faculty member billet in the NPS Department of Aeronautics and Astronautics, and while there, he earned a Ph.D. in aeronautical and astronautical engineering, with his research focused on helicopter aeromechanics.

Shortly after Mark arrived in 1999, I approached him with an offer he couldn’t refuse—to become the ACS teacher at NPS. Thankfully, he agreed to do this while he continued to teach his regularly assigned courses and worked on his Ph.D. In addition, to better serve the students at NPS, he expanded the ACS course to include reliability and systems safety engineering, and NPS gave it a new course title of Aircraft Combat Survivability, Reliability and System Safety Engineering (AA4251). In addition to this new course being offered as an in-resident course, Mark, with the help of Andy Cibula (also an NPS graduate) at the JTCG/AS and Ken Goff at NAVAIR, resurrected the NPS VTC ACS course and greatly increased the number of students by setting up new VTC sites at Patuxent River, China Lake, Lakehurst, Aberdeen Proving Ground, Wright- Patterson Air Force Base (AFB), Crystal City, Quantico, and Boeing-Philadelphia.

After Mark graduated with his Ph.D. in 2003, he was reassigned to another duty station and departed NPS, leaving NPS temporarily without an ACS teacher. Then another major change at NPS occurred soon after Mark left. In 2004, as a result of a possible Base Realignment and Closure (BRAC) action, the NPS Aeronautical Engineering program, which included a requirement for an ACS course similar to NPS AA4251, was moved to the Air Force Institute of Technology (AFIT) at Wright-Patterson AFB in Dayton, OH. A few of the NPS Department of Aeronautics and Astronautics faculty moved to AFIT with the transfer of the Aeronautical Engineering program; the rest either remained at NPS as part of the new Mechanical and Aerospace Engineering (MAE) Department or retired.

Unfortunately, due to the loss of a major source of aviator students to AFIT, the requirement for a new ACS teacher at NPS to teach AA4251 was not filled, and the NPS ACS course went into hibernation. The future of ACS education in 2004 did not look promising at NPS or AFIT. However, the JTCG/AS—now known as the Joint Aircraft Survivability Program (JASP)—short course did continue to be offered annually by Kevin Crosthwaite of the Survivability/ Vulnerability Information Analysis Center (SURVIAC) from 2003 through 2005.

Fortunately for ACS education, in 2005 Chris Adams was assigned to NPS as the Associate Dean of the Graduate School of Engineering and Applied Science (GSEAS). Chris had taken my NPS ACS course and was a thesis student of mine in the mid-1990s. When he returned to NPS as Associate Dean, he discovered that the ACS course was no longer being taught there. He was so concerned that the remaining aviator students at NPS were not learning about ACS that he approached the MAE Chair and volunteered to resurrect and teach AA4251, in addition to performing his normal responsibilities as Associate Dean. The MAE Chair at the time, Knox Millsaps (who now is the Director of the Division of Aerospace Sciences Research in the Office of Naval Research), wisely approved Chris’s proposal.

Chris not only took on the extra load of teaching AA4251, but he made a major modification to it. Because there were not as many aviator students left at NPS to take his ACS course, he developed a broader, multi-platform combat survivability course that would appeal to NPS students from all major military platforms: aircraft, surface ships and submarines, spacecraft, and eventually ground vehicles. This new course became Combat Survivability, Reliability, and Systems Safety Engineering (MAE4751). Chris knew this change would require many changes to the ACS course he took in the 1990s. He also knew that the NPS students to whom he would be teaching this new course would probably know a lot more about ships and submarines, spacecraft, and ground vehicles than he did. This was a risky venture, but Chris had the ability to successfully pull it off. His new NPS multi-platform combat survivability course has been taught twice a year since 2005.

Chris also developed a different, asynchronous, video-based, Internet-accessible course for Joint Combat Assessment Team (JCAT) personnel, and he has advised several thesis students looking at a wide range of survivability and lethality research projects.

In 2007, Mark retired from the Navy and joined the Institute of Defense Analyses (IDA), working on aircraft survivability issues. Once there, he became active again in the JASP short course presentations. Eventually, he and Chris joined forces, and they are now the lead instructors for the JASP ACS short course, which continues to be taught annually. The next offering of the JASP ACS short course (coordinated by DSIAC) will be on 27–29 March 2018 at Naval Air Station North Island in San Diego, CA.

As for me, after finishing the second edition of the textbook in 2003, I started the part-time development of a stand-alone, CD-based, Survivability Self-Study Program (SSSP). The JASP-funded SSSP, which was completed in 2009, provides a relatively quick, easy, and effective way to learn about the fundamentals of the ACS discipline. Nearly all of the material in the program has been taken from the prologue and chapter 1 of the textbook. (Readers can obtain a copy of the SSSP from DSIAC at

Finally, in 2011, Chris, Mark, and I began the development of a combat survivability educational program for Army and Marine ground vehicles, titled “The Fundamentals of Ground Vehicle Survivability and Force Protection (GVS&FP),” under the sponsorship of the Live Fire Test and Evaluation (LFT&E) Office. I worked on developing the fundamentals for a ground-vehicle-focused textbook based upon my work in ACS and ship survivability. Chris developed a short course with additional invited presenters (which has been offered annually since 2014), and Mark served as an advisor and presenter. At the end of 2016, I fully retired from all combat survivability activities, and the GVS&FP educational program was transferred to the U.S. Army’s Tank Automotive Research Development and Engineering Center (TARDEC) at the beginning of FY18.


The transfer of the NPS Aeronautical Engineering program from NPS to AFIT in 2004 created a need for an AFIT course similar to the earlier NPS ACS course. To meet that need, ACS education received another stroke of good fortune in 2007 when (then) MAJ Richard Huffman, a new AFIT Assistant Professor with a fresh Ph.D., accepted the responsibility for teaching Combat Aircraft Survivability (ASYS640) as part of the weapons specialty sequence. Rich took the opportunity to revamp the course curriculum and integrate it into the survivability research programs at Wright-Patterson and Eglin AFBs. The weapons specialty sequence includes four graduate-level courses in weaponeering, explosives, warhead design, and aircraft survivability to provide the students with a holistic approach to the aircraft’s mission, exposure, and kill chain.

Thanks to Rich’s efforts, ACS education became a permanent part of AFIT. During his 4 years there, he taught ACS to more than 150 students and advised 19 M.S. and 3 Ph.D. students, including his successor at AFIT, David Liu. The current AFIT ACS professor is Andrew Lingenfelter, who conducted his Ph.D. research under Dave Liu’s guidance. Due to the military assignments process, AFIT’s ACS professors receive new assignments every 3 to 4 years, but they nonetheless continue to remain dedicated to the ACS discipline after departing to other assignments. Currently, all three instructors actively participate in the JASP ACS short course even though only Andrew is still at AFIT.

Since 2013, the AFIT has conducted more than $500,000 worth of ACS research, has sponsored six M.S. students and one Ph.D. student, and has been published in numerous peer-reviewed ACS-related journals and conference proceedings. Additionally, AFIT has partnered with Wright- Patterson AFB units to jointly leverage resources for unique ballistic testing and research opportunities. The ACS course is one of the most popular and sought-after courses at AFIT due to the tremendous foresight and work of Rich Huffman, Dave Liu, and Andrew Lingenfelter.


To my knowledge, currently there is no other ACS course (covering all aspects of designing for survival in combat) offered at a degree-granting institution other than the ones at NPS and AFIT. I understand the U.S. Naval Academy briefly offered an undergraduate course in ACS sometime in the late 1980s or early 1990s (using the first edition of the AIAA ACS textbook), and I know that ACS was taught at the Naval Academy for a few years around 2011 by Brian Forney (a student of Chris’s), who was assigned to teach at the Academy. The only other educational activity related to the design for ACS that I am familiar with is the research and 5-day Aircraft Survivability short course on the design of military aircraft for combat survivability started by Prof. John Fielding in the 1990s at Cranfield University’s College of Aeronautics in England. Like me, John has remained active after his retirement in 2010, but his short course at Cranfield is being carried on by others.

In addition, there are a few civilian organizations that teach one or more aspects of ACS, usually in a short course format. These include the radar, infrared and electro-optic, and electronic warfare courses taught by Georgia Tech as a part of its Professional Education program.

In the military operations world, there is a special U.S. Army educational/training program known as tactical operations (TACOPS), which is heavily involved with improving the survivability of Army aviation in combat. In the early 1990s, after Operation Desert Storm, the Army identified a need for an aviation tactical officer who specialized in the use of aircraft survivability equipment (ASE) and an officer who specialized in electronic warfare (EWO). Subsequently, the aviation TACOPS officer career track was created in 1993. In 2003, the multi-week TACOPS Officer’s Course was established at Fort Rucker, AL, under the direction of CW5 Greg Fuchs. Eventually, the subjects of ASE and EWO were absorbed into the 6-week TACOPS course, which continues to use the AIAA ACS textbook as one of its major sources of ACS fundamentals.

The most recent educational opportunity in combat survivability is the 8-hr classified short course “Aerospace Survivability,” for aircraft and spacecraft, being offered for the first time during the AIAA Defense Forum, 10–11 May 2018, at Johns Hopkins University. The instructors are David Liu, Andrew Lingenfelter, and Steven Broussard (from Boeing).

(Note: If any readers are aware of other formal ACS educational offerings, I would be most grateful if they would email me at


Over the past 40 years, approximately 5,000 “students” have taken either the ACS academic course at NPS or AFIT or the JTCG/AS-JASP short course; and nearly 19,000 ACS hard-bound books (first and second editions) and CDs (second edition) have been sold.

Overall, ACS education is in great shape now, with highly capable ACS educators who have dedicated their careers to the ACS discipline and a leadership that believes in the value of that discipline. As discussed throughout this article, numerous organizations and individuals have been involved over the past 40 years, and they deserve special recognition for this success. They include:

  • The leadership of the JTCG/AS and JASP (currently led by Dennis Lindell) and the overseeing LFT&E Office (initially led by James O’Bryon and currently led by Sandra Ugrina) for providing intellectual and financial support over the past 40 years. Individually, I would like to thank Dale Atkinson for his vision, encouraging support, and mentoring from the beginning of this 40-year endeavor; Lowell Tonnessen for his wisdom, insight, and support while at IDA; and the many ACS practitioners in industry, the Services, and the military who taught me what ACS is all about.
  • The current generation of ACS primary educators—Mark Couch, Chris Adams, Rich Huffman, Dave Liu, and Andrew Lingenfelter—for saving the ACS educational program from a certain death and broadening it into a platform combat survivability program. Without their dedication, there would likely be no ACS educational program available to the DoD agencies and the military aviation industry today.
  • The many ACS short course volunteer lecturers who, although not always experienced in giving ACS presentations to large groups of students, enthusiastically participated in the program, thus ensuring its success. Short course presenters who have been particularly active over the recent past include Alan Brown (past Director of Engineering at Lockheed), Bill Dooley and Dave Legg from NAVAIR, and Greg Fuchs, along with others, from the Army’s Aircraft Shoot Down Assessment Team (ASDAT) and the multi-Service JCAT.

The ACS educational program is now on its way to its 50th anniversary. As new threats emerge over the next 10 years, the ACS discipline must continue to evolve to defeat those threats. New educational materials need to be developed to cover topics such as advanced anti-air weapons (including improved guns and guided missiles); new weapons with different damage mechanisms (such as lasers and cyber attacks); and the new topics of cyber survivability, aircraft recoverability, and force protection. Adding this new material will keep our ACS educational program relevant, timely, and essential.

Finally, I am convinced that the work of this current generation of ACS educators over the next 40 years will result in new generations of dedicated ACS educators who will strive to ensure that the aircrews that operate in a man-made hostile environment can accomplish their mission and return home, thanks to the combat survivability that has been intentionally built into their aircraft. And even if there is no one on board, we most likely will still want the aircraft back in one piece. And even if we don’t expect the aircraft to return, it must survive long enough to reach the intended target.


Dr. Robert E. Ball is an NPS Distinguished Professor Emeritus who has spent more than 33 years teaching ACS, structures, and structural dynamics in NPS’s Department of Aeronautics and Astronautics. As discussed, he has been the principal developer and presenter of the fundamentals of ACS over the past four decades and is the author of the seminal ACS text The Fundamentals of Aircraft Combat Survivability Analysis and Design (first and second editions), published by AIAA. In addition, his more than 55 years of experience have included serving as president of two companies (Structural Analytics, Inc., and Aerospace Educational Services, Inc.) and as a consultant to Anamet Labs, the SURVICE Engineering Company, and IDA. Dr. Ball holds a B.S., M.S., and Ph.D. in structural engineering from Northwestern University.


The author wishes to thank Christopher Adams, Mark Couch, and Andrew Lingenfelter for their contributions to this article. The author would also like to apologize for any errors or omissions in this personal perspective—40 years is a long time to hold on to so many memories.