Boeing C-17 Globemaster III For other aircraft with this designation, see C-17 (disambiguation). C-17 Globemaster IIIThe prototype C-17, known as T-1, flying a test sortie in 2007RoleStrategic and tactical airlifter National originUnited States Manufacturer McDonnell Douglas / Boeing First flight15 September 1991Introduction17 January 1995StatusIn servicePrimary usersUnited United United States Air Force Indian Air Force  Royal Air Force  See Operators for othersProduced1991–2015 Number built279Unit cost US$218 million (flyaway cost for FY 2007) Developed Douglas YC-15 The Boeing C-17 Globemaster III is a large military transport aircraft. It was developed for the United States Air Force (USAF) from the 1980s to 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 commonly performs tactical and strategic airlift missions, transporting troops and cargo throughout the world; additional roles include medical evacuation and airdrop duties. It was designed to replace the Lockheed C-141 Starlifter, and also fulfill some of the duties of the Lockheed C-5 Galaxy, freeing the C-5 fleet for outsize cargo. Boeing, which merged with McDonnell Douglas in 1997, continued to manufacture C-17s for export customers following the end of deliveries to the U.S. Air Force. Aside from the United States, the C-17 is in service with the United Kingdom, Australia, Canada, Qatar, United Arab Emirates, NATO Heavy Airlift Wing, India, and Kuwait. The final C-17 was completed at the Long Beach, California plant and flown on 29 November 2015. 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.The Advanced Medium STOL Transport (AMST) competition was held, with Boeing proposing the YC-14, and McDonnell Douglas proposing the YC-15.Though both entrants exceeded specified requirements, the AMST competition was canceled before a winner was selected. The Air Force started the C-X program in November 1979 to develop a larger AMST with longer range to augment its strategic airlift.   The McDonnell Douglas YC-15 design was used as the basis for the C-17. By 1980, the USAF found itself with a large fleet of aging C-141 Starlifter cargo aircraft. Compounding matters, USAF needed increased strategic airlift capabilities 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 elected to develop a new aircraft based on the YC-15. Boeing bid an enlarged three-engine version of its AMST YC-14. Lockheed submitted two designs, a C-5-based design and an enlarged C-141 design. On 28 August 1981, McDonnell Douglas was chosen to build its proposed aircraft, then designated C-17. Compared to the YC-15, the new aircraft differed in having swept wings, increased size, and more powerful engines.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 Clearer .At this time, first flight was planned for 1990. The Air Force had formed a requirement for 210 aircraft. Development problems and limited funding caused delays in the late 1980s.Criticisms were made of the developing aircraft and questions were raised about more cost-effective alternatives during this time. In April 1990, Secretary of Defense Dick Chesney 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. The first aircraft (T-1) and five more production models (P1-P5) participated in extensive flight testing and evaluation at Edwards Air Force Base.Two complete airframes were built for static and repeated load testing. Development difficulties A static test of the C-17 wing in October 1992 resulted in the wing failing at 128% of design limit load, which was below the 150% requirement. Both wings buckled rear to the front and failures occurred in stringers, spars and ribs. Some $100 million were spent to redesign t
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