C-17 Globemaster III Tactical Transport Aircraft, USA

The Boeing C-17 Globemaster III military airlift aircraft is capable of carrying payloads up to 169,000lb, and has an international range and the ability to land on small airfields. A fully integrated electronic cockpit and advanced cargo systems allow a crew of three; the pilot, copilot and loadmaster, to operate all systems on any type of mission.

Since it entered service in January 1995, over 171 aircraft have been delivered to the US Air Force with nine more on order. Deliveries are expected to conclude in 2008. A further 10 aircraft were ordered in December 2006, for delivery by October 2009.

The UK Royal Air Force has leased four aircraft, delivered by August 2001, under a seven-year agreement, which also has an end-of-lease purchase option.

In August 2006, a fifth aircraft (delivered in April 2008) was ordered and the purchase of the first four aircraft in 2008 was confirmed. In December 2007, the UK purchased a sixth aircraft, aircraft which was delivered in June 2008.

In March 2006, Australia selected the C-17, with a requirement for four aircraft. The first aircraft was delivered in December 2006, the second in May 2007, the third in February 2008 and the final aircraft in March 2008.

In July 2006, Canada announced the selection of the C-17 with a requirement for four aircraft. The contract was signed in February 2007. Deliveries began in August 2007 and concluded in April 2008.

In September 2006, NATO announced its intention to buy an initial three or four C-17 aircraft. In June 2007, an international consortium, consisting of fifteen NATO countries plus two partner countries (Finland and Sweden), agreed to set up the Strategic Airlift Capability (SAC) which will be based at Papa Air Base in Hungary.

A new NATO Airlift Management Organisation (NAMO) will purchase, own, and manage the aircraft. A multinational military unit, the Heavy Airlift Wing (HAW), will conduct airlift operations. In May 2008, SAC requested the Foreign Military Sale of the first two C-17 aircraft. Deliveries are planned to begin in November 2008 and conclude in 2009.

In March 2007, Boeing announced that C-17 production would conclude in 2009, when current orders have been fulfilled.

Flight-testing of the C-17 using a blend of synthetic fuel and JP-8 began in October 2007, as part of a USAF process to develop more-efficient fuel for its fleet, with less reliance on imported petrol. Certification for the aircraft powered by synthetic fuel is expected to be completed in early 2008.

C-17 design

A propulsive lift system allows the C-17 to achieve safe landings on short runways. The C-17 is capable of landing a full payload in less than 3,000ft. The propulsive lift system uses engine exhaust to generate lift: the engine exhaust is directed onto large flaps, which extend into the exhaust stream, allowing the aircraft to fly a steep approach at a relatively low landing speed.

The aircraft is capable of turning in a small radius and can complete a 180-degree star turn in 80ft. The aircraft can also carry out routine backing. A fully loaded aircraft is capable of backing up a 2% gradient slope using the directed flow thrust reversers.

Cockpit

The C-17 cockpit accommodates pilot, co-pilot and two observer positions. The digital avionics system has four Honeywell multi-function cathode-ray tube displays, two full-capability HUDs Head-Up Displays) plus cargo systems.

The quadruple-redundant electronic flight control system also has a mechanically-actuated backup system.

There are two Lockheed Martin central processing computers, one Hamilton Sundstrand data management computer and two Honeywell air data computers.

A program to upgrade the C-17A avionics includes new mission computers and displays, new software for the warning and caution system, being provided by Northrop Grumman Navigation Systems. The automatic flight control system will be upgraded with BAE Systems Controls CsLEOS real-time operating system and will be certified for GATM (Global Air Traffic Management) system requirements.

Cargo systems

The design of the cargo compartment allows the C-17 to carry a wide range of vehicles, palleted cargo, paratroops, air-drop loads and aeromedical evacuees.

The cargo compartment has a sufficiently large cross-section to transport large wheeled and tracked vehicles, tanks, helicopters (such as the AH-64 Apache), artillery, and weapons such as the Patriot missile system. Three Bradley armoured vehicles comprise one deployment load on the C-17. The US Army M1A1 main battle tank can be carried with other vehicles.

The maximum payload is 170,900lb (77,519kg) with 18 pallet positions, including four on the ramp. Airdrop capabilities include: single load of up to 60,000lb (27,216kg), sequential loads of up to 110,000lb (49,895kg), Container Delivery System (CDS) airdrop up to 40 containers, 2,350lb (1,066kg) each; up to 102 paratroops.

The aircraft is equipped for LAPES (Low Altitude Parachute Extraction System) drops. For Medevac, the C-17 can transport up to 36 litter and 54 ambulatory patients and attendants.

Countermeasures

The C-17 is equipped with BAE Systems Integrated Defense Solutions (formerly Tracor) AN/ALE-47 countermeasure flare dispensers and the ATK AN/AAR-47 missile warning system.

AN/AAR-47 has a suite of surface-mounted thermal sensors around the aircraft, which detect the thermal signature of the missile exhaust plume. Frequency selection and signal processing techniques are used to minimise the false alarm rate. The system provides a warning to the crew via the cockpit indicator unit of the presence and direction of the missile threat. A signal is automatically sent to the ALE-47 dispenser.

AN/ALE-47 is capable of carrying a mix of expendable countermeasures, including jammers. The system interfaces to the C-17 aircraft's sensors. The aircrew can select the mode of operation of the dispenser for fully automatic, semi-automatic or manual operation.

The cockpit control unit can be used to input mission data, together with the numbers and types of expendable countermeasures systems loaded into the ALE-47. The cockpit controller updates and displays the status of the dispenser and the numbers and types of countermeasures remaining.

The ALE-47 is capable of dispensing the new-generation active expendable decoys, POET and GEN-X, in addition to the conventional chaff and flare decoys that are compatible with the previous-generation ALE-40 and ALE-39 dispensers.

56 USAF C-17 aircraft are being equipped with the Northrop Grumman Large Aircraft Infrared Countermeasures (LAIRCM) system.

LAIRCM is based on the AN/AAQ-24(V) NEMESIS. It entered low-rate initial production in August 2002 and completed initial operational test and evaluation in July 2004. 25 upgraded aircraft have been delivered. The system is scheduled to enter service in 2007. The four aircraft leased by the UK RAF will also be fitted with LAIRCM.

Turbofan engines

The four Pratt and Whitney PW2040 turbofan engines are integrated in the wings. Engine thrust reversers, which are operable in flight, and speedbrakes enable the aircraft to carry out rapid deceleration and descent manoeuvres.

The cruise speed is between Mach 0.74 and 0.77. The range without in-flight refuelling, and with a payload of 160,000lb, is 2,400nm. Aerial refuelling provides an intercontinental non-stop range.