Flight-Test Transformation

Oct. 1, 2012

The Air Force flight-test community is searching for a new way to thrive—and preserve its legendary ethos in the 21st century. Today, the Air Force fleet is smaller than any time since its inception in 1947. This gritty reality of fiscal austerity has asserted itself on the flight-test community, where the broad range of Cold War programs is an increasingly fond memory.

An F-111 trails behind during B-1B testing.

While the 1950s and 1960s were the Golden Age of flight test, with Cold War budgets and urgencies fueling rapid and overlapping programs, the modern flight-test arena is about long-term sustainment programs on vehicles already in service, some for decades. The differences are profound, but the Air Force flight-test community has accommodated similar changes in the past.

Flight testing of US military aircraft began when the Wright brothers validated their design before demonstrating and selling it to the Army in 1909. Eventually, the test methodology grew into an effort conducted by the manufacturer to test an aircraft before turning it over to the air service whose military pilots and engineers would then verify or challenge the manufacturer’s claims.

To be sure, air service engineers were involved from the outset of a project, but the testing regimen for production aircraft was largely sequential in nature. Though pioneers such as the Wrights and Glenn H. Curtiss test-flew their own early designs, the maturation of the commercial test process gave rise to hired civilian test pilot heroes of the 1930s and ’40s.

Phase Testing

But the cachet of military test pilots was on the rise. Starting with a seminal survey of various company flight-test operations during World War II, the Army Air Forces began inserting itself into the test process earlier. This saved money and time by cutting duplicative test efforts; USAAF testers argued it also gave the service a better product sooner, putting end user oversight into the process early on.

The evolution of postwar Air Force flight-test methodology was characterized by phase testing, which became the model for development of production aircraft between the late 1940s and 1958.

The eight phases alternated between the contractor and the Air Force, but the rhythm and compression of these efforts enabled the F-86 Sabre to enter operational service only 16 months after the prototype’s first flight.

If phase testing codified Air Force participation earlier in aircraft development, it represented largely chronological rather than integrated development and testing by the Air Force and the contractor. By 1958, an abbreviated category-testing rationale replaced the eight phases with three categories. The contractor performed Category I, USAF performed Category II, and major commands performed Category III. The category model was simpler, but the developmental tests were not. It was the dawn of weapon systems and complex operations that needed to interact flawlessly.

A Galaxy at Edwards AFB, Calif., during testing in the C-5 Reliability Enhancement and Re-engining Program. (Photo by Jet Fabara)

The category-testing model came under criticism in the 1960s during the F-111 program, which embraced concurrent development, testing, and production. Although mutual USAF-contractor presence was specified in the categories, the contractor had lead responsibility for Category I and the Air Force for Category II. The Air Force decried the amount of time and duplicated effort. Ultimately, the F-111 became an important and successful combat tool, but its pained gestation may have suggested a more desirable test methodology for modern high-performance aircraft.

The F-111, critics argued, was merely a “paper airplane” when it won its competition against another company’s design. The Department of Defense turned away from concurrent development and production of aircraft and embraced a fly-before-buy policy.

Along with this development came the 1972 combined testing model. A combined test force (CTF), typically led by an Air Force officer, put Air Force and contractor pilots and engineers in the mix from the outset of a program. Defining differences in the developmental and operational sides of Air Force flight testing, the service categorized combined testing into development testing and evaluation, plus initial operational test and evaluation, leading to a combined operational test and evaluation before any production decisions were completed.

The 1970s witnessed several fly-off demonstrations at Edwards AFB, Calif., where the Air Force chose the A-10 over the A-9, the demonstration YF-16 and YF-17 each metamorphosed into the production F-16 and F/A-18, and the Boeing YC-14 and Douglas YC-15 both introduced high-lift transport concepts, some of them eventually showing up in the C-17.

T-1, USAF’s first C-17, takes off from Long Beach, Calif., to Edwards in 1991 for testing. Globemaster IIIs entered unit service even before testing was complete. (Boeing photo) testing.

The currently favored CTF model involves several USAF disciplines along with those of contractors to deliver the best aircraft in the least time. Fly-before-buy has hedged over the years to accommodate the developmental cost of new military aircraft, with initial low-rate production, reminiscent of the old pre-World War II service test regime. Aircraft such as the C-17 have entered unit service even while the test program was still ongoing at Edwards, with incremental performance envelope increases issued to operational units as more of the envelope was cleared.


Some in the test community say the CTF model has devolved into something less than its creators intended. Budget-driven hollowing of the government developmental test corps has led to increased contractor roles in the CTF, critics contend. As far as budgets are concerned, USAF’s development, test, and evaluation effort, as a percentage of the larger research, development, test, and evaluation enterprise, slipped from about 9.8 percent in 1996 to around 7.3 percent by 2005, according to a 2008 report by the Defense Science Board Task Force.

If current ratios of government-to-contractor developmental testers in the CTF mix have changed, the basic CTF model is nonetheless sound, argues retired Maj. Gen. Curtis M. Bedke, who was commander of the Air Force Flight Test Center from 2004 to 2007 and the Air Force Research Laboratory until his 2010 retirement.

A YF-16 and a YF-17, both carrying AIM-9 Sidewinder missiles. The YF-16 became USAF’s F-16, and the YF-17 became the Navy’s F/A-18. (Photo by R. L. House)

Bedke calls the CTF “an inherently solid, flexible, and disciplined organizational structure that has served the Air Force and flight test very well over the years.” There is no “flaw or old-think” to the CTF concept, Bedke asserts; both contractor and Air Force voices are heard throughout an entire process that involves contractor and engineers, test pilots, and management. “It ensures testing is done once, and done right, with the understanding and agreement of everyone involved in the process,” he argues.

The pace of new aircraft designs also forces the flight-test world to re-evaluate how it delivers the best weapon systems to customers. How are USAF’s flight-test and procurement communities adjusting to the realities of fewer programs but longer timelines?

Realignments within Air Force Materiel Command indicate some movement in this area. In mid-2012, AFMC folded its 12 centers into five.

A name change makes the Air Force Flight Test Center at Edwards, simply the Air Force Test Center. It oversees AFMC’s test mission at three major sites.

In addition to the work at Edwards, realignments at Eglin AFB, Fla., put the 46th Test Wing into the newly designated 96th Test Wing. Along with the 412th Test Wing at Edwards, the 96th TW aligns under the test center. Meanwhile, the Arnold Engineering and Development Center at Arnold AFB, Tenn., was redesignated the Arnold Engineering Development Complex and also aligned under the test center.

Brig. Gen. Arnold W. Bunch Jr., the first commander of the newly redesignated Air Force Test Center at Edwards, says critical test activity is accomplished across the AFMC test enterprise at Eglin, Arnold, Edwards, Holloman AFB, N.M., and a variety of smaller sites. “My job is to show the same amount of love to all of the locations and all of the test enterprise,” he explains.

A YC-15 on display at the Edwards gate. (USAF photo by SrA. Stacy Sanchez)

Bunch takes the global view of the service’s test enterprise. “Instead of a laser-beam focus on Edwards Air Force Base test activities, … my focus is enterprise-wide test activities,” he says. For the first time, he notes, all aspects of AFMC testing (anechoic chambers, computational modeling, weapon systems, cyber, flight, ground, wind tunnel, and others) align under a single center. This presents tremendous opportunities to standardize processes across the test enterprise for effectiveness and efficiency, Bunch points out.

The reorganization was designed to take overhead costs out of various staffs through consolidation. No staffing cuts were made below the wing level. The net savings for AFMC’s entire reorganization is based upon 1,000 fewer positions and a savings of more than $100 million annually.

The consolidation and realignment of test activities is emblematic of Air Force realities in an era where a spectrum of threats must be countered, coupled with the effects of a lingering economic downturn. A balancing act requires the Air Force to maintain a prudent technological edge, while addressing asymmetric threats such as terrorism. At the same time, observers note an exodus of experienced testers in the last decade as the wave of Cold War civilians and Active Duty members retire. Force drawdowns have kept replacements at a level some consider too low to maintain managerial proficiency and corporate knowledge.

Charles E. Adolph, a former contractor test engineer who subsequently spent more than a quarter-century as a military and civil service engineer and technical director at Edwards before moving on to OSD, expresses concern about an unintended gutting of the flight-test enterprise’s core talent in the era of tight budgets.

The Importance of Timing

Reducing the number of experienced developmental testers in the name of cash savings is a false economy, Adolph says. Loosening government requirements by substituting commercial standards has, too often, only proved why specific government requirements were levied in the first place. The best service is rendered to the Air Force and the American taxpayer, he believes, when informed government developmental testers are involved with the program office from the planning stages to ensure normal developmental problems are identified soon enough to correct before production.

A KC-135 (r) runs an icing test on an A-10. (DOD photo)

“Failure to identify and admit to technical issues and solutions, as well as real costs, early in the program cycle is the overwhelming cause for subsequent cost increases and schedule delays,” Adolph notes. “Robust testing early in development, and objective assessment of test progress, are absolutely essential, to allow for early identification and correction of design deficiencies.”

The timing of flight testing late in the research and development sequence can inadvertently work against the flight-test enterprise’s ability to deliver. Bill Flanagan, a retired USAF test veteran who participated in flight test both as an Air Force officer and a Northrop B-2 flight-test weapon systems officer, observed test programs running over time and over budget with design and delivery problems, only getting resolved at the expense of those who make up the tail end of the development process: the flight testers.

“As the cost rises and the lateness becomes apparent, there will be pressure to cut the length of the flight-test program to release the development and testing personnel to cut expenses despite the fact they are the ones most needed to conclude the test program. Since testing comes last, there will be pressure to reduce testing since it is what is not yet completed,” Flanagan wryly notes.

Flanagan’s prescription for effective flight test in an increasingly austere budget environment is a resuscitation of the lean flight-test program for the F-111 Pave Tack night attack-guided weapons system in the late 1970s.

Preserving Infrastructure

With only two flight crews and a small staff including contractor engineers, the Pave Tack operation used developmental test missions that involved operational-style weapons delivery—closely mirroring actual employment of an F-111 in combat. As a result, the initial operational test crew gained valuable experience as well as two to three test mission flights per week. The initial flight-test program was completed in approximately eight months and the lesson for the future, per Flanagan, was that greater efficiencies of time and cost can be realized by blending developmental and operational test goals.

Lt. Jacob Fickel (r) demonstrates how he fired the first shot from an airplane, testing the use of weapons from the air. Aircraft designer Glenn Curtiss is at the controls. (USAF photo)

Flanagan also suggests the proper CTF dynamic might need more, not less, contractor involvement to economically deliver the right product on time. He adds it could be more helpful to use more thoroughly integrated CTF teams for even less duplication of effort.

The Air Force flight-test infrastructure is touted as a national asset, but could tight budgets force it to shed capabilities and facilities

“The basic infrastructure must be preserved; as less testing occurs, this means the cost per program of the ‘invested infrastructure’ will be higher,” Bedke responds. “But one doesn’t reduce the size of the airspace by half if the number of aircraft are cut in half; the runway isn’t reduced in length by 50 percent; the array of radars and unique, one-of-a-kind test facilities can’t be reduced.”

On the other hand, he says, some things can and should be reduced. One also always needs to consider the long term and the impact of cutting some capabilities that may take years or decades to recover once lost. Bedke acknowledges detrimental effects of budget belt-tightening that have left some aspects of Air Force test infrastructure hurting, in need of repair or modernization.

“Someone will have to ensure that the important things are recapitalized even in an austere budget environment,” he says. The replacement of Edwards’ deteriorating half-century-old 15,000-foot paved runway in 2008 was one such investment—and more are called for. Even with prudent recapitalization, the changing world of flight test may drive decisions to mothball or even divest some Air Force test assets, he acknowledges.

A Minuteman rocket motor undergoes testing at the Arnold Engineering Development Complex, Tenn. (Photo by Rick Goodfriend )

Bunch must keep an eye on how test capacity reductions take place and the associated effects. “I almost worry more about the human capital” than the physical plant, he says, because of the long lead time to reconstitute lost experience. “Test skills aren’t conferred with a degree to a new engineering graduate. They must be built in-house, over time, and gained through experience,” he says.

Air Force flight test can expect to operate with smaller budgets and smaller staffs in the next decade. Hard decisions must be made, and infrastructure must be upgraded where needed and shed where obsolete. The erosion of seasoned talent in the government test discipline has caused problems and must be corrected by ramping up recruitment and retention.

At the same time, the combined test force model is sound and needs to be exercised fully. Some may argue for more participation by the government side. Others say contractors could fill staffing gaps. Government testers—the informed customers—must insert themselves in development programs to discover and fix problems early—before a weapon system enters production. Developmental and operational testing, although different in some aspects, can overlap in many areas to achieve economy of motion.

Slackers don’t endure in the stark Mojave Desert surrounding Edwards. The Air Force Test Center faces a much smaller number of programs, fading budgets, and the need for long aircraft lifespans. To be successful, it will need the same brand of can-do gusto that saw America’s first jet flight in 1942, the first supersonic flight in 1947, and numerous test programs since.

Frederick A. Johnsen is the director of the Air Force Flight Test Center Museum at Edwards AFB, Calif. He is the author of more than 24 books and monographs on aviation topics, including Fire Bombers in Action. His most recent article for Air Force Magazine, “Attacking Fires From the Air,” appeared in the October 2010 issue.