C17 Globemaster III
- 1 Mission
- 2 Features
- 3 Background
- 4 Wartime usage
- 5 Units using the C-17
- 6 Specifications (C-17)
- 6.1 General characteristics
- Crew: 3 (2 pilots, 1 loadmaster)
- Cargo: 170,900 lb (77,500 kg)
- Troops: 102, regular or airborne
- Medevac: 36 litter and 54 ambulatory patients
- Length: 174 ft (53 m)
- Wingspan: 169.8 ft (58 m)
- Height: 55.1 ft (16.8 m)
- Wing area: 3,800 ft² (353 m²)
- Empty: lb ( kg)
- Loaded: lb ( kg)
- Maximum takeoff: 585,000 lb (265,500 kg)
- Powerplant: 4 × Pratt & Whitney F117-PW-100 turbofans, 40,440 lbf (180 kN) thrust
- Maximum speed: 450 knots (830 km/h)
- Cruise speed: 390 knots (722 km/h)
- C-17: 2,400 nm (4,400 km)
- C-17ER: 2,800 nm (5,200 km)
- Service ceiling: 45,000 ft (13,700 m)
- Rate of climb: ft/min ( m/min)
- Wing loading: lb/ft² ( kg/m²)
- 6.1 General characteristics
The C-17 Globemaster III is the newest, most advanced, and most flexible cargo aircraft to ever enter the U.S. and allied airlift force. It is capable of rapid strategic delivery of troops and all types of cargo to main operating bases or directly to forward bases in the deployment area. This aircraft is also capable of performing tactical airlift and airdrop missions when required. The inherent flexibility and performance of the C-17 force improves the ability of the total airlift system to fulfill the worldwide air mobility requirements of the United States.
The ultimate measure of airlift effectiveness is the ability to rapidly project and sustain an effective combat force close to a potential battle area. Threats to U.S. interests have changed in recent years, and the size and weight of U.S. mechanized firepower and equipment have grown in response to improved capabilities of potential adversaries. This trend has significantly increased air mobility requirements, particularly in the area of large or heavy outsize cargo. As a result, newer and more flexible airlift aircraft such as the C-17 are needed to meet potential armed contingencies, peacekeeping or humanitarian missions worldwide.
Reliability, a high degree of safety, and maintainability are three outstanding benefits of the C-17 system. Current operational requirements impose demanding reliability and maintainability. These requirements include an aircraft mission completion success probability rate of 92 percent, only 20 aircraft maintenance man-hours per flying hour, and full and partial mission availability rates of 74.7 and 82.5 percent, respectively. The Boeing warranty assures these figures will be met.
The aircraft is powered by four, fully reversible, FAA-certified F117-PW-100 turbofan engines (the Department of Defense designation for the commercial Pratt and Whitney PW2040, currently used on the Boeing 757.) Each engine is rated at 40,440 lbf (180 kN) of thrust. The thrust reversers direct the flow of air upward and forward to avoid ingestion of dust and debris. Maximum use has been made of off-the-shelf and commercial equipment, including Air Force-standardized avionics.
The aircraft is operated by a crew of three (pilot, copilot, and loadmaster), reducing manpower requirements, risk exposure and long-term operating costs. Cargo is loaded onto the C-17 through a large aft door that accommodates military vehicles and palletized cargo. The C-17 can carry all of the Army's air-transportable equipment, including the 70-ton M1 main battle tank.
Maximum payload capacity of the C-17 is 170,900 lb (77,500 kg), and its maximum gross takeoff weight is 585,000 lb (265,350 kg). With a payload of 160,000 lb (72,600 kg) and an initial cruise altitude of 28,000 ft (8,500 m), the C-17 has an unrefueled range of approximately 2,400 nautical miles (4,400 km) on the first 71 units, and 2,800 nautical miles (5,200 km) on all subsequent units, which are extended-range models with an additional fuel tank in the center wing box. Its cruise speed is approximately 450 knots (833 km/h) (.74 Mach). The C-17 is designed to airdrop 102 paratroopers and equipment.
The superior design of the C-17 allows it to operate through small, austere airfields. The C-17 can easily take off and land on runways as short as 3,000 ft (900 m) and only 90 ft (27 m) wide. In addition, the C-17 can also operate out of unpaved, unimproved runways due to the rugged design of the landing gear system, as well as operate out of runways much shorter then 3,000 feet. Even on such narrow runways, the C-17 can turn around using a three-point star turn and its backing capability.
The C-17 was designed and built by McDonnell-Douglas, which was acquired by Boeing in 1997. It was based upon an earlier McDonnell-Douglas product, the YC-15. This aircraft was the result of a runoff with the Boeing YC-14 in the Advanced Medium STOL Transport project. However, the project was canceled before a winner was selected.
By the early-1980s, the USAF found itself with a very large, but aging fleet of C-141 Starlifters. Some of the C-141s had major structural problems as a result of heavy use. USAF also has historically never had sufficient strategic airlift capabilities to fulfill its requirements. They elected to use the YC-15 as the basis for a new aircraft. This aircraft, by then designated the C-17A Globemaster III was ordered in August 1981. The new aircraft differed in having swept wings, increased size, and more powerful engines. This would allow it to perform all work performed by the C-141, but to also fulfill some of the duties of the C-5 Galaxy, so that the C-5 fleet would be freed up for larger, more outsize cargo.
Development continued until December, 1985 when a full-scale production contract was signed. Its maiden flight was on September 15, 1991 from the McDonnell-Douglas west coast plant in Long Beach, California. This aircraft (T-1) and five more production models (P1-P5) participated in extensive flight testing and evaluation at Edwards AFB.
The first production model was delivered to Charleston Air Force Base, S.C., on July 14, 1993. The first squadron of C-17s, the 17th Airlift Squadron, was declared operationally ready on January 17, 1995.
The Air Force originally programmed to buy a total of 120 C-17s, with the last one being scheduled for delivery in November 2004. The fiscal 2000 budget funded another 14 aircraft for Special Operations Command. Basing of the original 120 C-17s is planned for Charleston AFB; McChord AFB (first aircraft arrived in July 1999); Altus AFB; and at an Air National Guard unit in Jackson, Miss. Basing of the additional 14 aircraft to McGuire AFB NJ Elemendof AK Hickham HI Dover AFB DE and Travis AFB CA. An additional 60 units were ordered in May of 2002. The Department of Defense studied a report to order an additional 42 aircraft, which would have also involved decommissioning some early C-5 Galaxys. After the report concluded that the service should not order more aircraft, the Senate overrode the DoD and passed legislation to order the additional allotment.
USAF originally intended to acquire about 350 units, though this was reduced at the end of the Cold War. However, USAF has been so pleased and amazed with the aircraft that it is entirely possible that the C-17 will be ordered in greater quantities than originally envisioned, with current orders standing at 222.
The C-17 is operated by the Air Mobility Command at the 437th Airlift Wing, Charleston AFB, S.C.; the 62nd Airlift Wing, McChord AFB, Wash; and the 315th Airlift Wing (Associate Reserve), Charleston AFB, S.C.
Boeing has actively marketed the C-17 to many European nations including Belgium, Britain, France, and Spain. Of these, Britain was always seen as the most likely customer given its increasingly expeditionary military strategy and global commitments. The Royal Air Force has established an aim of having interoperability and some weapons and capabilities commonality with the United States Air Force. The UK's 1998 Strategic Defence Review identified a requirement for a strategic airlifter following the protracted procurement of the European airlifter, the Airbus A400M. The Short-Term Strategic Airlift (STSA) competition commenced in September of that year. The UK cancelled the competition in August 1999 recognizing that the C-17 was the only aircraft that met its demanding specifications.
The UK Defence Secretary, Geoff Hoon, announced in May 2000 that the RAF would lease four C-17s from Boeing for an initial seven years with an optional two year extension. At this point the RAF would have the option to buy the aircraft or return them to Boeing. The UK committed to upgrading the C-17s in line with the USAF so that in the event of them being returned to Boeing the USAF could adopt them.
The first C-17 was delivered to the RAF at Boeing's Long Beach facility on May 17, 2001 and flown to RAF Brize Norton by No. 99 Squadron which had previously trained with USAF crews to gain competence on the type. The RAF's fourth C-17 was delivered on August 24, 2001. The RAF aircraft were some of the first to take advantage of the new centre wing fuel tank.
The RAF declared itself delighted with the C-17 and reports began to emerge that they wished to retain the aircraft regardless of the A400M's progress. Although the C-17 fleet was to be a fallback for the A400M, the UK announced on July 21, 2004 that they have elected to buy their four C-17s at the end of the lease, even though the A400M is moving towards production. They will also be placing a follow-on order for one aircraft, though there may be additional purchases later, especially if the A400M does not live up to expectations in operational use. While the A400M is described as a "strategic" airlifter, the C-17 gives the RAF true strategic capabilities that it would not wish to lose, for example a maximum payload of 77,000 kg compared to the Airbus' 37,000 kg. The fifth aircraft will be ordered with the USAF's additional order for 42.
In RAF service the C-17 has not been given an official designation (e.g. C-130J referred to as Hercules C4 or C5) due to its leased status, but is referred to simply as the C-17. Following the end of the lease period the four aircraft will assume an RAF designation, most likely "Globemaster C1." Presumably, should the additional aircraft enter service prior to this, it alone will carry the C1 designation for a time.
The 2004 Indian Ocean earthquake and resultant tsunamis placed a strain on the global strategic airlifter pool. The impressive performance of the C-17 in USAF and RAF service have persuaded Germany to consider acquiring 2-4 C-17s for the Luftwaffe in a dry lease arrangement, at least until the A400M is available in 2009. German Foreign Minister Joschka Fischer stated in the German news magazine Der Spiegel that the government needed its own organic strategic transport capability to be able to respond to disasters in a better manner than it was able to for this incident. During the tsunami relief effort, Germany tried to acquire transport through its usual method of wet leasing Antonov airlifters via private companies, but found to its dismay that there were no available aircraft. While the stated goal of a C-17 lease would be to last until the A400M's arrival, it is always possible that the Luftwaffe may undergo an experience similar to that of the RAF, and elect to retain them.
The C-17 was used to deliver military goods and humanitarian aid during Operation Enduring Freedom in Afghanistan as well as Operation Iraqi Freedom in Iraq by both services. On March 26, 2003, ten USAF C-17s participated in the biggest combat airdrop since Operation Just Cause in Panama in December, 1989. The night-time airdrop of 1,000 soldiers occurred over Bashur, Iraq. It opened the northern front to combat operations and constituted the largest formation airdrop since D-Day in World War II.
Units using the C-17
United States Air Force
- Altus AFB
- Charleston AFB
- Elmendorf AFB (crews in training - no aircraft yet as of 2005)
- Hickam AFB (crews in training - no aircraft yet as of 2005)
- March ARB
- McChord AFB
- McGuire AFB
- Allen C. Thompson Field ANGB
- Travis AFB (crews in training - no aircraft yet as of 2005)
Royal Air Force
Inventory: 4 C-17ER (+1 C-17ER on order)