By Al Moyers, Headquarters Air Force Operational Test and Evaluation Center Director of History and Research
/ Published June 20, 2007
KIRTLAND AIR FORCE BASE, N.M. -- On Oct. 18, 2006, the Air Force Operational Test and Evaluation Center's Detachment 5 at Edwards AFB, Calif., reported the last test event for the operational assessment of the C-5 Reliability Enhancement and Re-engining Program had been completed. The C-5 RERP assessment is the latest in a long run of operational test and evaluations of the C-5 Galaxy that AFOTEC has conducted since the Air Force established it as the Service's operational test agency.
Since its introduction more than three decades ago, the C-5 has been an integral part of the U.S.'s strategic airlift fleet, yet the aircraft has been controversial nearly its entire life. Over those years, reliability rates for the aircraft have dropped as its engines and avionics have aged. Yet, many programmers argue that the Air Force cannot afford not to modernize the Galaxy, the Air Force's largest airlifter.
By the beginning of the 1960s, both aviation industry and Department of Defense leaders had begun looking at the requirement for a large jet transport to replace aging cargo aircraft in the Air Force inventory, including the Douglas C-124 Globemaster II and the Douglas C-133 Cargomaster. This proposed new aircraft was to augment the fleet of Lockheed C-141 Starlifter jet transports then being produced for the Air Force.
In October 1961, planners in Air Force headquarters issued an operational requirement to the Military Air Transport Service, which was re-designated the Military Airlift Command in 1966 and inactivated in 1992 with the establishment of Air Mobility Command, for a new transport program designated CX-4. However, the Army contested the CX-4 program in August 1962, stating the program did not represent any "significant advance" over the C-141. Subsequently, Air Force planners released a new requirements document on June 20, 1963, for the CX-X, which eventually became the Cargo Experimental-Heavy Logistics System, or CX-HLS.
The Boeing Company, the Douglas Aircraft Company, the General Dynamics Corporation, the Lockheed-Georgia Company, and the Martin Marietta Corporation each submitted design proposals for the CX-HLS in mid-1964. Soon thereafter, program managers in Air Force Systems Command, which was inactivated in 1992 with the activation of Air Force Materiel Command, awarded three-month design study contracts to Boeing, Douglas, and Lockheed. Aviation engineers at all three companies incorporated high-wing configurations with four large turbofan engines into their designs. The Boeing and Douglas designs had conventional tail configurations, whereas the Lockheed design incorporated a T-tail configuration.
On Sept. 30, 1965, Robert S. McNamara, Secretary of Defense from 1961 to 1968, announced that Lockheed, with its Model L-500, had been awarded the CX-HLS contract. The C-5, as the new aircraft was designated, was to be bought using the new Total Package Procurement process, wherein a single contractor was responsible for concurrent development and production under a single fixed-price contract with negotiated incentives.
In his recently released autobiography, Dr. John L. McLucas, who passed away in 2002 and was Secretary of the Air Force from 1973 to 1975, states that Gen. Bernard A. Schriever, commander of the Air Force Systems Command from 1959 to 1966, pushed for the C-5 to be a monumental leap in technology. In aggregate, however, the requirements were well beyond the technology of the time and came to represent the foundation of future problems for the C-5.
Lockheed engineers soon realized that the aircraft was too heavy to meet the payload and range requirements. Air Force program managers insisted Lockheed meet the lift requirements and agreed to Lockheed's proposal to meet the requirements by reducing the C-5's weight by reducing the thickness of the primary wing component and using a higher stress threshold for the wing. The first C-5 rolled out of Lockheed's Marietta, Ga., plant on March 2, 1968. Lockheed pilots completed the first flight on June 30, 1968.
In July 1969, tests on the C-5 indicated wing failure at 84 percent of the modified design load. The evaluation estimated that the weight-reduced wing had a useful life expectancy of slightly more than 25 percent of the desired service hours.
But, Air Force leaders chose (although some argue they were forced given the overwhelming need for additional lift in Southeast Asia) to live with the compromised C-5 wing by limiting the operation of the C-5 to less payload, shorter range, and reduced flying hours. By mid-1970, when wing fatigue began to occur across the C-5 fleet, the 40th C-5A was being assembled and Lockheed employees were already machining wing parts for the 60th airframe.
A former AFOTEC historian suggested in an early organizational history that the term cost overrun had been coined to describe the C-5 program. The historian was no doubt being somewhat facetious, but Secretary McLucas confirmed in his autobiography that when he became Undersecretary of the Air Force in 1969 the C-5 had already "encountered embarrassing cost overruns and performance problems."
The design problems and cost overruns resulted in the C-5 procurement program receiving scrutiny from many fronts. The C-5 was barely off the ground before Sen. E. William Proxmire, chairman of the Senate Armed Services Committee, began committee hearings on the C-5's cost overruns and technical deficiencies.
Observers like Senator Proxmire regarded the C-5 as one of the most appalling examples of tax dollar waste. Finding the Services unwilling or unable to enforce such contracts, Secretary of Defense McNamara abandoned Total Package Procurement. To reduce the cost of the program, the administration of President Richard M. Nixon, who had campaigned for the presidency on defense acquisition reform, decreased the total C-5A procurement from 115 to 81 aircraft. After delivery of the last C-5A, Aeronautical Systems Division, today's Aeronautical Systems Center, calculated the cost of the C-5A was $1 billion more than the original TPP contract and had in the end purchased 31 fewer aircraft.
The need for modern, heavy lift capability in Southeast Asia and elsewhere was so great the Air Force, acknowledging the C-5A wing problem, pressed the new transport quickly into service. The first C-5A squadron attained initial operational capability in September 1970. By mid 1971, C-5 crews had begun delivering war supplies to Southeast Asia.
Late in 1973, Lockheed proposed to modify the C-5 wing to restore the aircraft to full operational capability and increase the wing service life to the original specification. The crash of a C-5A at Ton Son Nhut Air Base, South Vietnam in April 1975 killed more than 75 infants, which were being evacuated from the war, arguably was a factor in convincing the principals to resolve the known structural and performance deficiencies of the aircraft. The Air Force awarded Lockheed a new contract in December 1975 to again modify the C-5A wing. Using technology that had not existed at the time of the original design, Lockheed completed the re-design of the C-5A wing in June 1978.
An October 1978 modification to the program management directive -- the seventh amendment -- reflected Secretary of Defense Harold Brown's direction for the Air Force Test and Evaluation Center, activated three years after the C-5 achieved initial operating capability and re-designated the Air Force Operational Test and Evaluation Center in 1983, to participate in an extensive test and evaluation of the C-5. The AFTEC C-5 test team first published its follow-on operational test and evaluation plan for the C-5A wing modification program in November 1979.
On April 8, 1980, before the follow-on testing was complete, Deputy Secretary of Defense W. Graham Clator requested AFTEC conduct an operational utility evaluation to analyze the C-5A's performance in forward operating location, off-pavement operations. With growing concerns about C-5 capabilities in Congress and within the Department of Defense, this evaluation evolved over time to consider the influence of a variety of weather effects on C-5 ground operations.
AFTEC testers completed the off-pavement/weather effects OUE in July 1981 and concluded that the C-5A performed well off-pavement on fine grained soils and performed satisfactorily in 12 to 14 inches of virgin snow; but certain weather conditions, such as rain-soaked soils or heavily packed or layer-crusted snow, had the potential to create serious limitations.
Like the OUE, the scope of the follow-on operational test and evaluation of the modified wing changed and AFTEC re-published the plan in November 1981. Maj. Gen. Wayne E. Whitlatch, AFTEC commander from 1980 to 1982, signed the results of phase one of the follow-on operational test and evaluation of the modified C-5A in December 1981. Overall, the modified aircraft's operational effectiveness and suitability were found to be satisfactory at that time, although there were some concerns.
AFTEC testers continued with phase two of follow-on operational testing and evaluation of the modified C-5A during 1982 to re-address concerns about the modified C-5A's reliability, cruise performance, and fuel leaks in the new wing structure. Reliability and maintainability of modified aircraft were evaluated to be essentially the same as that of unmodified C-5s. Test results showed the airplane's cruise performance was degraded slightly, but not enough to dictate a revision of published performance data. A fix was developed for the fuel leak, but the evaluation concluded that until its full implementation, availability and operating performance of the fleet would be constrained, but offset by the increase in the amount of cargo that could be lifted.
In October 1982, before the last of the wing-modified C-5As was delivered in 1987 and after considering acquisition of the Boeing 747 and what is now the Boeing C-17, the Air Force awarded Lockheed a contract for 50 C-5Bs. These updated Galaxies included the modified wing structure, upgraded engines, and improved avionics. The initial flight of the prototype was performed on Sept. 30, 1985, and the first C-5B deliveries were made to the Air Force in January 1986.
As was the practice, before Chief of Staff of the Air Force General Merrill A. McPeak directed in 1992 that the major air commands essentially transfer their operational test and evaluation resources to AFOTEC, personnel from the Military Airlift Command's Airlift Center conducted the follow-on operational test and evaluation of the C-5B. Members of AFOTEC simply monitored the progress of the MAC evaluation of the C-5B. The final C-5Bs were delivered to the Air Force in April 1989.
With the added mission of conducting "all" operational test and evaluation, AFOTEC test teams were involved in the operational test and evaluation of other updates to the C-5 during the 1990s, including the All Weather Flight Control System and the Global Positioning System/Flight Management System Integration.
Many in industry and government continued to call for additional modernization of the C-5. An Air Force study group determined the C-5 still had 80 percent of its airframe service life remaining and that enhancements could extend the feasible life of the C-5 to 2040. In September 1998 Lockheed Martin proposed a commercial-off-the-shelf plan to update the C-5 fleet with new avionics and engines.
The Air Force awarded Lockheed Martin an Avionics Modernization Program contract in 1999, including upgrades to communication, navigation, and air traffic management systems. These upgrades included those Secretary of Defense William J. Perry directed for Air Force transports following the crash of an Air Force CT-43 on approach to Dubrovnik, Croatia, in 1996, killing Secretary of Commerce Ronald H. Brown and 34 others onboard. In sum, Air Force planners intended AMP to give the C-5 a modern flight deck to operate safely around the globe with a digital backbone to provide the wherewithal to upgrade the avionics during future modifications.
On Dec. 5, 2001, the Air Force awarded Lockheed Martin the RERP contract to install new turbofan engines, pylons, thrust reversers and wing attachment fittings to the C-5 fleet. The new power plants were expected to produce more thrust and thus provide a shorter take-off roll, a higher climb rate to initial altitude, an increased cargo load, and a longer range between refueling. Moreover, program managers believe RERP would increase C-5 fleet availability, which in 2006 was reported as the lowest in Air Mobility Command, while reducing total operating costs, which was reported in 2006 to be the highest for AMC.
In January 2002 the Air Force integrated the C-5 AMP and RERP programs into a two-phased program to more efficiently implement the overall C-5 modernization effort. Avionics capability required for modernization that was not complete at the end of phase one of the modernization program, AMP, was funded as part of phase two, RERP, and included electrical, hydraulic, fuel, fire suppression and pressurization subsystems as well as auxiliary power units, air conditioning systems, landing gear and the airframe.
The first aircraft to be modified under C-5 AMP was brought into Lockheed Martin's Marietta, Ga., facility on June 12, 2002. Lockheed pilots first flew the upgraded aircraft in December 2002. Maj. Gen. Felix Dupre, commander of AFOTEC from February 2003 to April 2005, signed the C-5 AMP qualification operational test and evaluation plan on May 5, 2004. The first upgraded aircraft was delivered to the Air Force in October 2004 and less than a year later, on Sept. 7, 2005, AFOTEC testers began the C-5 AMP QOT&E.
However, AFOTEC leadership paused the evaluation on Oct. 12, 2005; and did not resume the QOT&E until April 21, 2006. The C-5 AMP QOT&E test team completed the last test event on July 11, 2006, and Maj. Gen. Robin E. Scott, who assumed AFOTEC command in June 2005, signed the C-5 AMP QOT&E report on Nov. 3, 2006. The test team recognized that the C-5 AMP "enhances existing strategic airlift," but still has limitations.
The first C-5 RERP modification began in October 2004; was completed on May 16, 2006, and the first flight of the C-5M, the new designation given to the aircraft upgraded under RERP, occurred on June 19, 2006. General Scott signed the C-5 RERP operational assessment test plan on June 28, 2006. The C-5 RERP OA began on July 26, 2006. The C-5 RERP OA report, which General Scott signed Nov. 29, 2006, provided a progress update on the C-5M program for the low rate initial production decision. The C-5M production run is scheduled to begin in 2008 and continue through 2013.
The C-5 modernization program is one of the actions needed to bring the nation's airlift capability up to the level recommended in a recent military mobility study. The Galaxy has been a valuable national asset for nearly four decades. The C-5 has supported every major contingency since the Vietnam War. The C-5 is a regular contributor to disaster relief operations around the world. And, in every effort, the C-5 has compiled staggering statistics. For example, during Operation Desert Storm, C-5 crews delivered more cargo in little more than two weeks of flying than the entire payload carried during the Berlin Airlift.
Curiously, however, many critics have failed to see the need for the C-5 despite its long and unique value to the strategic airlift capability of the nation. The C-5 was again in the spotlight earlier this year when on April 3, 2006, a Galaxy crashed, the sixth in its history, while making an emergency approach to Dover AFB, Del. The C-5 will retain its role as the Air Force's largest airlifter for the foreseeable future. It is probably safe to state that future C-5 crewmembers and future AFOTEC evaluators will fly and test another updated Galaxy in yet another decade in the 21st century.