The McDonnell Douglas/Boeing C-17 Globemaster III is a large military transport aircraft developed for the United States Air Force (USAF) during the 1980s and the early 1990s by McDonnell Douglas. The C-17 carries forward the name of two previous piston-engined military cargo aircraft, the Douglas C-74 Globemaster and the Douglas C-124 Globemaster II.
The C-17 is based upon the YC-15, a smaller prototype airlifter designed during the 1970s. It was designed to replace the Lockheed C-141 Starlifter, and also fulfill some of the duties of the Lockheed C-5 Galaxy. The redesigned airlifter differs from the YC-15 in that it is larger and has swept wings and more powerful engines. Development was protracted by a series of design issues, causing the company to incur a loss of nearly US$1.5 billion on the program's development phase. On 15 September 1991, roughly one year behind schedule, the first C-17 performed its maiden flight. The C-17 formally entered USAF service on 17 January 1995. McDonnell Douglas and later Boeing after it merged with McDonnell Douglas in 1997, manufactured the C-17 for more than two decades. The final C-17 was completed at the Long Beach, California, plant and flown in November 2015.
The C-17 commonly performs tactical and strategic airlift missions, transporting troops and cargo throughout the world; additional roles include medical evacuation and airdrop duties. The transport is in service with the U.S. Air Force along with the air forces of India, the United Kingdom, Australia, Canada, Qatar, the United Arab Emirates, Kuwait, and the Europe-based multilateral organization Heavy Airlift Wing.
The aircraft played a key logistical role during both Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom in Iraq, as well as in providing humanitarian aid in the aftermath of various natural disasters, including the 2010 Haiti earthquake, the 2011 Sindh floods and the 2023 Turkey–Syria earthquakes.
Development
Background and design phase In the 1970s, the U.S. Air Force began looking for a replacement for its Lockheed C-130 Hercules tactical cargo aircraft."Air Force Lets Advanced STOL Prototype Work." The Wall Street Journal, 13 November 1972. The Advanced Medium STOL Transport (AMST) competition was held, with Boeing proposing the YC-14, and McDonnell Douglas proposing the YC-15.Miles, Marvin. "McDonnell, Boeing to Compete for Lockheed C-130 Successor." Los Angeles Times, 11 November 1972. Though both entrants exceeded specified requirements, the AMST competition was canceled before a winner was selected. The USAF started the C-X program in November 1979 to develop a larger AMST with longer range to augment its strategic airlift.Kennedy 2004, pp. 3–20, 24.
By 1980, the USAF had a large fleet of aging C-141 Starlifter cargo aircraft. Compounding matters, increased strategic airlift capabilities were needed to fulfill its rapid-deployment airlift requirements. The USAF set mission requirements and released a request for proposals (RFP) for C-X in October 1980. McDonnell Douglas chose to develop a new aircraft based on the YC-15. Boeing bid an enlarged three-engine version of its AMST YC-14. Lockheed submitted both a C-5-based design and an enlarged C-141 design. On 28 August 1981, McDonnell Douglas was chosen to build its proposal, then designated C-17. Compared to the YC-15, the new aircraft differed in having swept wings, increased size, and more powerful engines.Norton 2001, pp. 12–13. This would allow it to perform the work done by the C-141, and to fulfill some of the duties of the Lockheed C-5 Galaxy, freeing the C-5 fleet for outsize cargo.
Alternative proposals were pursued to fill airlift needs after the C-X contest. These were lengthening of C-141As into C-141Bs, ordering more C-5s, continued purchases of KC-10s, and expansion of the Civil Reserve Air Fleet. Limited budgets reduced program funding, requiring a delay of four years. During this time contracts were awarded for preliminary design work and for the completion of engine certification. In December 1985, a full-scale development contract was awarded, under Program Manager Bob Clepper."Douglas Wins $3.4B Pact to Build C-17." Los Angeles Times, 3 January 1986. At this time, first flight was planned for 1990.Norton 2001, pp. 13, 15. The USAF had formed a requirement for 210 aircraft.Kennedy 2004, pp. 70, 81–83.
Development problems and limited funding caused delays in the late 1980s.Kennedy, Betty Raab. "Historical Realities of C-17 Program Pose Challenge for Future Acquisitions." Institute for Defense Analyses, December 1999. Criticisms were made of the developing aircraft and questions were raised about more cost-effective alternatives during this time.Fuller, Richard L. "More load for the buck with C-17." Chicago Tribune, 9 September 1989.Sanford, Robert. "McDonnell Plugs Away on C-17." St. Louis Post-Dispatch, 3 April 1989. In April 1990, Secretary of Defense Dick Cheney reduced the order from 210 to 120 aircraft. The maiden flight of the C-17 took place on 15 September 1991 from the McDonnell Douglas's plant in Long Beach, California, about a year behind schedule."C-17's First Flight Smoother Than Debate." The New York Times, 17 September 1991. The first aircraft (T-1) and five more production models (P1-P5) participated in extensive flight testing and evaluation at Edwards Air Force Base."RL30685, Military Airlift: C-17 Aircraft Program." Congressional Research Service, 5 June 2007. Two complete airframes were built for static and repeated load testing.Norton 2001, pp. 25–26, 28.
Development difficulties A static test of the C-17 wing in October 1992 resulted in its failure at 128% of design limit load, below the 150% requirement. Both wings buckled rear to the front and failures occurred in stringers, spars, and ribs."Technical Assessment Report; C-17 Wing Structural Integrity." Department of Defense, 24 August 1993. Retrieved: 23 August 2011. Some $100 million was spent to redesign the wing structure; the wing failed at 145% during a second test in September 1993. A review of the test data, however, showed that the wing was not loaded correctly and did indeed meet the requirement."Findings, Conclusions and Recommendations of the Executive Independent Review Team." US Government Executive Independent Review Team via blackvault.com, 12 December 1993. The C-17 received the "Globemaster III" name in early 1993. In late 1993, the U.S. Department of Defense (DoD) gave the contractor two years to solve production issues and cost overruns or face the contract's termination after the delivery of the 40th aircraft.Evans, David."Pentagon to Air Force: C-17 flunks." Chicago Tribune, 29 March 1993. By accepting the 1993 terms, McDonnell Douglas incurred a loss of nearly US$1.5 billion on the program's development phase.
In March 1994, the Non-Developmental Airlift Aircraft program was established to procure a transport aircraft using commercial practices as a possible alternative or supplement to the C-17. Initial material solutions considered included: buy a modified Boeing 747-400 NDAA, restart the C-5 production line, extend the C-141 service life, and continue C-17 production. The field eventually narrowed to: the Boeing 747-400 (provisionally named the C-33), the Lockheed Martin C-5D, and the McDonnell Douglas C-17. The NDAA program was initiated after the C-17 program was temporarily capped at a 40-aircraft buy (in December 1993) pending further evaluation of C-17 cost and performance and an assessment of commercial airlift alternatives.
In April 1994, the program remained over budget and did not meet weight, fuel burn, payload, and range specifications. It failed several key criteria during airworthiness evaluation tests."Air Force Letter To Douglas Spells Out 75 Defects For C-17." Los Angeles Times, 28 May 1991."C-17 fails engine start test." Press-Telegram, 12 April 1994."Parts Orders for C-17 far too high, GAO says." Charlotte Observer, 16 March 1994. Problems were found with the mission software, landing gear, and other areas."The C-17 Proposed Settlement and Program Update." United States General Accounting Office, 28 April 1994. In May 1994, it was proposed to cut production to as few as 32 aircraft; these cuts were later rescinded.Kreisher, Otto."House rescinds cuts in C-17 program." San Diego Union, 25 May 1994. A July 1994 Government Accountability Office (GAO) report revealed that USAF and DoD studies from 1986 and 1991 stated the C-17 could use 6,400 more runways outside the U.S. than the C-5, but these studies had only considered runway dimensions, but not runway strength or load classification numbers (LCN). The C-5 has a lower LCN, but the USAF classifies both in the same broad load classification group. When considering runway dimensions and load ratings, the C-17's worldwide runway advantage over the C-5 shrank from 6,400 to 911 airfields. The report also stated "current military doctrine that does not reflect the use of small, austere airfields", thus the C-17's short field capability was not considered."Comparison of C-5 and C-17 Airfield Availability." United States General Accounting Office, July 1994.
A January 1995 GAO report stated that the USAF originally planned to order 210 C-17s at a cost of $41.8 billion, and that the 120 aircraft on order were to cost $39.5 billion based on a 1992 estimate."C-17 Aircraft – Cost and Performance Issues." United States General Accounting Office, January 1995. In March 1994, the U.S. Army decided it did not need the low-altitude parachute-extraction system delivery with the C-17 and that the C-130's capability was sufficient. C-17 testing was limited to this lower weight. Airflow issues prevented the C-17 from meeting airdrop requirements. A February 1997 GAO report revealed that a C-17 with a full payload could not land on wet runways; simulations suggested a distance of was required."C-17 Globemaster – Support of Operation Joint Endeavor." United States General Accounting Office, February 1997. The YC-15 was transferred to AMARC to be made flightworthy again for further flight tests for the C-17 program in March 1997.Bonny et al. 2006, p. 65.
By September 1995, most of the prior issues were reportedly resolved and the C-17 was meeting all performance and reliability targets."Air Force Secretary Says Modernization, C-17 on Track." Air Force magazine, 19 September 1995."Future Brightens for C-17 Program." Press-Telegram, 31 March 1995. The first USAF squadron was declared operational in January 1995."Air Force fills Squadron of C-17s ." Associated Press, 18 January 1995.
Production and deliveries
In 1996, the U.S. DoD ordered another 80 aircraft for a total of 120.Kilian, Michael."In Record Procurement U.S. Orders 80 C17s – Plane Good Deal for 2,000 jobs in California." Chicago Tribune, 1 July 1996. In 1997, McDonnell Douglas merged with domestic competitor Boeing. In April 1999, Boeing offered to cut the C-17's unit price if the USAF bought 60 more; in August 2002, the order was increased to 180 aircraft."$9.7 Billion U.S. Deal for Boeing C-17's." The New York Times, 16 August 2002. In 2007, 190 C-17s were on order for the USAF."Boeing Company Funds Extension." Boeing, 9 July 2008. On 6 February 2009, Boeing was awarded a $2.95 billion contract for 15 additional C-17s, increasing the total USAF fleet to 205 and extending production from August 2009 to August 2010.Trimble, Stephen."Boeing in $3bn air force contract." Flight International, 10 February 2009. On 6 April 2009, U.S. Secretary of Defense Robert Gates stated that there would be no more C-17s ordered beyond the 205 planned.Cole, August and Yochi J. Dreazen. "Pentagon Pushes Weapon Cuts." The Wall Street Journal, 7 April 2009, p. 1. However, on 12 June 2009, the House Armed Services Air and Land Forces Subcommittee added a further 17 C-17s.Kreisher, Otto. "House panel reverses cuts in aircraft programs." Congress Daily, 12 June 2009.