The AW101 (EH101) military utility medium lift helicopter is manufactured by AgustaWestland (formerly EH Industries), a joint venture company formed by Agusta of Italy and the British company GKN. AgustaWestland is now wholly owned by Finmeccanica. The EH101, now renamed the AW101, is also produced in naval and civil versions. 146 AW101 variants have been ordered and over 120 delivered.
AW101 orders
22 AW101 Merlin HC3 medium support helicopters have been delivered to the UK Royal Air Force, the first entered service in January 2001. 44 have been completed for the UK Royal Navy.
Italy ordered 20 AW101 with deliveries beginning in July 2000. These are eight ASW with L-3 Communications HELRAS active dipping sonar (deliveries complete), four AEW, four utility and four amphibious support helicopters (deliveries began July 2006).
Canada ordered 15 AW101 Cormorant variants for search and rescue, which entered service in 2002. Denmark ordered 14 search and rescue and troop transport variants in September 2001. Deliveries began in January 2006. Portugal ordered 12 search and rescue and combat SAR in 2002. The first was delivered in December 2004 and deliveries completed in July 2006. Kawasaki delivered the first licence-built AW101 to Japan in March 2007.
In September 2003, Japan ordered 14 AW101 utility helicopters for airborne mine countermeasures and Antarctic survey transport. Deliveries began in March 2006.
In July 2002, AgustaWestland signed an agreement with Lockheed Martin to jointly market and produce a version of the helicopter for the US market, the US101. In February 2005, the helicopter was chosen as the replacement helicopter for the US Marine One presidential transport fleet requirement. The helicopter was proposed by Team US101, led by Lockheed Martin.
First flight of a new, higher performance variant of the AW101 took place in September 2006. This variant is fitted with British Experimental Rotor Programme (BERP) IV composite main rotor blades, more powerful CT7-8E engines rated at 1884kW and a new integrated cockpit display system with five 10in x 8in LCD displays.
In March 2007, the UK Royal Air Force agreed to buy six new AW101 already delivered to Denmark. The helicopters were transferred to the RAF in June 2007. They are being fitted with new BERP main rotor blades and will enter service in 2008. Denmark will receive replacement helicopters.
Modular design
The rugged modular structure incorporates crashworthy and damage-tolerant features, including a five-blade main rotor, four-blade teetering rotor and main lift frame, which includes multiple primary and secondary load paths.
"The AW101 has crashworthy and damage-tolerant features."The fuselage is mainly of aluminium-lithium construction. The aerodynamic rotor blades are constructed from carbon / glass with nomex honeycomb and rohacell foam. Active vibration control of the structural response (ACSR) uses a vibration-cancelling technique.
The helicopter operates in temperatures ranging from -40°C to +50°C.
An ice protection system allows operation in known icing conditions. An engine inlet particle separator system provides protection in sandy environments. High flotation tyres and efficient landing gear permit operation from soft or rough terrain.
EH101 cockpit
The cockpit is equipped with armoured crew seats able to withstand an impact velocity of 35ft/s. Dual flight controls are provided for the pilot and copilot, but the helicopter is capable of being flown by a single pilot.
The pilot's mission display unit is supplied by Northrop Grumman (formerly Litton). The electronic instrument system includes six high-definition, full-colour displays, together with an optional mission display.
A forward-looking infrared (FLIR) system display and digital map can be installed. Portuguese and Danish Air Force helicopters have FLIR Systems Star SAFIRE thermal imagers. DRS Technologies of the USA supplies the flight control computers.
EH101s for Denmark and Italy are being fitted with Selex Communications LOAM Laser Obstacle Avoidance and Monitoring system.
Military utility and naval weapons
Naval versions of the AW101 can be armed with two anti-ship missiles, or up to four torpedoes and depth charges.
Armament options for military utility variants include a chin turret for a 12.7mm machine gun or pintle-mounted machine gun. The stub wings provide the hard points for mounting of rocket pods.
"The helicopter operates in temperatures ranging from
-40°C to +50°C."Countermeasures
The AW101 is equipped with infrared jammers, such as the Northrop Grumman Nemesis, directed infrared countermeasures, missile approach warners, chaff and flare dispensers, and a laser detection and warning system.
Cargo systems
The military version AW101 has accommodation for 30 seated or 45 standing fully equipped combat troops. The cabin has room for a medical team and 16 stretchers or for palleted internal loads. The maximum ramp load is 3,050kg for vehicles such as Land Rovers.
The heavy-duty cabin floor and ramp are equipped with flush tie-down points, a roller conveyer for palleted freight and a cargo winch for non self-loading freight. An underslung load hook is capable of carrying external loads up to 12,000lb, and the load measurement is displayed in the cockpit. A rescue hoist and a hover trim controller are fitted at the cargo door.
Avionics and mission systems
The AW101 is equipped with two military standard 1553B multiplex databuses, which link the helicopter management, avionics and mission systems. The Smiths Industries OMI SEP 20 automatic flight control system is a dual redundant digital system, which provides autostabilisation and four-axis auto-pilot operation.
The navigation system includes a global positioning / inertial navigation system, instrument landing system (ILS), VHF omnidirectional radio range (VOR), tactical air navigation (TACAN) and automatic direction finding.
AW101 engine
The military version of the AW101 is powered by either three General Electric CT7-6 turboshaft engines, rated at 1,491kW, or three Rolls-Royce Turbomeca RTM322 turboshaft engines, rated at 1,567kW.
"The military AW101 has accommodation for 30 to 45 fully equipped combat troops."Each engine is fed from a dedicated self-sealing fuel tank using dual booster pumps and a crossfeed system. The Rolls-Royce engine has been chosen by UK, Canada, Japan, Denmark and Portugal. The GE engine was selected by Italy.
The three tanks hold 3,222l of fuel. The fourth tank acts as a reservoir supply to top up the main tanks during flight. There is capacity for an additional transfer tank to increase the helicopter's range.
The range can be extended by the hover in-flight refuelling (HIFR) capability. The crew are able to select pressure refuel, defuel, jettison and buddy-to-buddy refuelling.
