AgustaWestland AW109
The AgustaWestland AW109, originally the Agusta A109, is a lightweight, twin-engine, eight-seat multi-purpose helicopter designed and initially produced by the Italian rotorcraft manufacturer Agusta. It was the first all-Italian helicopter to be mass-produced. Its production has been continued by Agusta's successor companies, presently Leonardo, formerly AgustaWestland, merged into the new Finmeccanica since 2016.
Development of the A109 commenced during the late 1960s as an indigenous rotorcraft suited to commercial operations. A twin-engine arrangement was pursued in response to market interest, while work on the civil model was prioritised over the military-orientated A109B project. On 4 August 1971, the first of three prototypes made its maiden flight. On 1 June 1975, the type received certification from the Federal Aviation Administration, permitting its service entry in 1976. The A109 has been used in a wide variety of roles, including light utility, VIP transport, aeromedical, law enforcement, search and rescue, and several military roles. Dedicated military models have been produced for both land and sea operations. Several models with alternative engines, expanded fuselages, and alternative equipment fitouts have been produced. Some AW109s feature a convertible interior to quickly adapt the rotorcraft between roles. Various third-party companies also offer adaptions and services for the type.
Following the merger of Agusta and the British company Westland Helicopters to form AgustaWestland, the A109 was rebranded as the AW109. International involvement in the programme has also been pursued; the company has established final assembly lines at sites in both Italy and the US. Furthermore, hundreds of AW109 fuselages have been manufactured by the Polish aerospace company PZL-Świdnik since the mid-1990s. AgustaWestland formed a joint venture with the Changhe Aircraft Industries Corporation in 2004 that produces and supports the AW109, includes a final assembly line, in China. The AW109 has been in continuous production for 40 years. The AgustaWestland AW119 is a derivative of the AW109, the principal difference being that it is powered by a single engine and has a fixed undercarriage.
Development
Origins
Work on what would become the AW109 commenced during the late 1960s at the Italian helicopter manufacturer Agusta, which sought to design an indigenous rotorcraft suitable for commercial activities. Known as the A109, early designs were of a single-engine helicopter. However, the design team came to recognise that the market found a twin-engine rotorcraft more attractive, so the project was revised in 1969, to outfit it with a pair of Allison 250-C14 turboshaft engines. While early considerations had been made for a militarised model, which the company internally referred to as the A109B, Agusta intentionally placed a low priority on the work for this variant in favour of other market sectors. In particular, design efforts were concentrated on the eight-seat A109C model.On 4 August 1971, the first of three prototypes performed the type's maiden flight. The A109 was subject to a protracted flight testing phase, which was largely attributable to the discovery of dynamic instability that took roughly one year to resolve via a modified transmission design. Almost four years later, the first production helicopter was officially completed during April 1975. On 1 June 1975, the type received certification for visual flight rules from the Federal Aviation Administration, permitting the A109 to be operated in North America.
During 1976, deliveries of production A109s commenced to civil customers. The type offered several advantages over the then-market leading Bell 206, including its greater top speed, twin-engine redundancy, and increased seating capacity. In 1975, Agusta's design team revisited the concept of a military version; to support their work, a series of flying trials were carried out between 1976 and 1977 involving a total of five A109As that had been outfitted with Hughes Aircraft-built TOW missiles. From these endeavours, two different military versions of the A109 emerged, one being intended for light attack/close air support missions while the other was optimised for shipboard operations.
Further development
Shortly following after the launch of the initial production model, Agusta begun work on additional models, primarily for the civil sector. During 1981, an A109A Mk2, that featured a widened cabin, was made available to operators. In 1993, the A109 K2 model was introduced, which was powered by alternative engine in the form of the Turbomeca Arriel 1K1. During 1996, the A109 Power was launched, which was broadly similar to the K2 except for the adoption of yet another powerplant, the Pratt & Whitney Canada PW206 engine. By 2008, according to AgustaWestland, the A109 Power was being operated across 46 countries. In 2006, an enlarged variant, the A109S Grand, was introduced.The A109 was renamed the AW109 as a consequence of the July 2000 merger of Finmeccanica and GKN plc's respective helicopter subsidiaries Agusta and Westland Helicopters to form AgustaWestland. Since the mid-1990s, fuselages for the AW109 have been manufactured by PZL-Świdnik, which became a subsidiary company of AgustaWestland in 2010. In June 2006, the 500th fuselage was delivered by the Polish aerospace company PZL-Świdnik, marking 10 years of co-operation on the AW109 between the two companies. In 2004, AgustaWestland formed a joint venture with the Changhe Aircraft Industries Corporation for the support and production of the AW109 in China; by 2009, the joint venture was reportedly capable of performing the final assembly of the AW109 in addition to independently manufacturing major sections, such as the fuselage.
In February 2014, AgustaWestland announced the development of the AW109 Trekker, an updated model. It is equipped with skid landing gear and is powered by a pair of FADEC-equipped Pratt & Whitney Canada PW207C engines; its avionics are supplied by Genesys Aerospace, which have been designed for single-pilot operations. The Trekker reportedly expands upon the utility capabilities of the standard AW109. Akin to the prior models, the final assembly of the AW109 Trekker is undertaken at sites in both the US and Italy.
Design
The AW109 is a lightweight twin-engine helicopter, known for its speed, elegant appearance and ease of control. Since entering commercial service, several revisions and iterations have been made, frequently introducing new avionics and engine technologies. AgustaWestland have promoted the type for its multirole capabilities and serviceability. The type has proven highly popular with VIP/corporate customers; according to AgustaWestland, 50% of all of the AW109 Power variant had been sold in such configurations. Other roles for the AW109 have included emergency medical services, law enforcement, homeland security missions, harbor pilot shuttle duty, search and rescue, maritime operations, and military uses. In 2008, AgustaWestland claimed the AW109 to be "one of the industry’s best-selling helicopters".A range of turboshaft powerplants have been used to power the numerous variants of the AW109, from the original Allison 250-C14 engines to the Turbomeca Arriel 1K1 and Pratt & Whitney Canada PW206 of more modern aircraft. Powerplants can be replaced or swapped for during airframe overhauls, resulting in increasing lifting capacity and other performance changes. In the case of single-engine failure, the AW109 is intended to have a generous power reserve even on a single engine. The engines drive a fully articulated four-blade rotor system. Over time, more advanced rotor blade designs have been progressively adopted for the AW109's main and tail rotors, such as composite materials being used to replace bonded metal, these improvements have typically been made with the aim of reducing operating costs and noise signature. According to Rotor&Wing, the type is well regarded for its "high, hot, and heavy" performance.
According to AgustaWestland, the AW109 Power features various advanced avionics systems, these include a three-axis autopilot, an auto-coupled Instrument Landing System, integrated GPS, a Moving Map Display, weather radar, and a Traffic Alerting System. These systems are designed to reduce pilot workload and enable the use of night vision goggles to conduct day-or-night operations. The AW109 has a forced trim system which can be readily and selectively activated by the controlling pilot using triggers located on the cyclic and collective which hold the control inputs at the last set position if activated. All critical systems are deliberately redundant for fail-safe operations; the hydraulic system, hydraulic actuators, and electrical system are all dual-redundant, while the power inverters are triple-redundant. The AW109 also has reduced maintenance requirements due to an emphasis on reliability across the range of components used.
Some models of the AW109 feature the "quick convertible interior", a cabin configuration designed to be flexibly re-configured to allow the rotorcraft to be quickly adapted for different roles, such as the installation or removal of mission consoles or medical stretchers. Mission-specific equipment can also be installed in the externally accessible separate baggage compartment, which can be optionally expanded. Optional cabin equipment includes soundproofing, air conditioning, and bleed air heating. Aftermarket cabin configurations are offered by third parties; Pininfarina and Versace have both offered designer interiors for the AW109, while Aerolite Max Bucher has developed a lightweight emergency medical service interior. The majority of AW109s are fitted with a retractable wheeled tricycle undercarriage, providing greater comfort than skids and taxiing capability. For shipboard operations, the wheeled landing gear is reinforced, deck mooring points are fixed across the lower fuselage, and extensive corrosion protection is typically applied.
Optional mission equipment for the AW109 has included dual controls, a rotor brake, windshield wipers, a fixed cargo hook, snow skis, external loudspeakers, wire-strike protection system, engine particle separator, engine compartment fire extinguishers, datalink, and rappelling fittings. A range of armaments can be installed upon the AW109, including pintle-mounted machine guns, machine gun pods, 20mm cannons, rocket pods, anti-tank missiles and air-to-air missiles. Those AW109s operated by the U.S. Coast Guard, later designated as MH-68A, had the following equipment installed: a rescue hoist, emergency floats, FLIR, Spectrolab NightSun search light, a 7.62 mm M240D machine gun and a Barrett M107 semi-automatic 12.7 mm anti-material rifle with laser sight.