AgustaWestland is preparing for a ramp-up in the development of its AW609 civil tiltrotor as it moves toward the beginning of certification flights early next year.

The company, which bought out Bell Helicopter's share of the tiltrotor program back in 2011, admits progress has been slow on the project. However, officials point out that some of this has been due to preparatory work to boost aircraft performance and ultimately help lower the manufacturing cost when serial production of the aircraft begins in the coming years.

The company is now targeting 2017 for certification of the tiltrotor under the FAA's Powered Lift category, and first deliveries to customers are now expected to take place at the end of 2017 or early 2018.

AgustaWestland's tiltrotor flight- test team is closing in on the end of envelope exploration trials using the first and second prototypes of the aircraft based in Arlington, Texas—home of the U.S.-based AgustaWestland Tiltrotor Co.—and at Cascina Costa, AgustaWestland's main test facility near Milan.

Test pilots are expected to finalize the type's auto-rotation capabilities in the coming weeks, before starting aero-elastic stability flight trials for the certification program. Both prototypes have so far completed around 870 flight hours combined.

Plans to have the second pair of AW609 prototypes flying in 2013 and 2014 have now been pushed back, according to the AW609's program head Clive Scott. Both prototypes require final assembly but are currently stored at AgustaWestland's development facility here at Cascina Costa. In mid-2014, the third prototype, AC3, will be transferred to the company's main production site at Verigiate, where it will be assembled by a team in order to give production engineers experience in how to assemble the aircraft. That prototype will be used for the development of the anti-icing system, while AC4 will fly in 2015 and act as a testbed for the Rockwell Collins Fusion avionics suite.

Choice of the Fusion avionics suite— announced in July 2012—was, according to company engineers, a result of the aircraft's development legacy with Bell, and the company's initial choice of the Rockwell Collins Pro Line 21. But AgustaWestland engineers are working to ensure that the system retains commonality with other AgustaWestland products. The company is pushing its AW139, 169 and 189 as a family of aircraft delivering reduced training requirements between each model, and some level of shared parts. The new avionics suite will introduce new features such as electronic circuit breakers, which have also been adopted for use on the company's twin-engine AW169.

Production aircraft will also feature an upgraded version of the PT6 turboshaft, the PT6C-67A, which is due to be certified in 2015. BAE Systems will provide the flight control computers for the tiltrotor's complex fly-by-wire control system, which also doubles as the digital engine control system.

The pace of tests slowed during 2013 as engineers worked on a series of drag- and weight-reduction programs. The aircraft has been given a new-design vertical stabilizer and tail cone, as well as more aerodynamic engine exhaust nozzles and changes to the rotor-spinner cones. Engineers say the changes have helped to reduce drag on the aircraft by around 10% and resulted in a “significant” weight reduction.

Maximum takeoff weight of the AW609 is currently 16,800 lb., but the company plans to add the option to boost this to around 18,000 lb. with what it calls a short-takeoff capability, using a rolling takeoff. AgustaWestland had planned to conduct flight tests using a specially built STOL strip at Cascina Costa, but this facility is yet to be built, and it may struggle to proceed due to the location's close proximity to Milan's busy Malpensa Airport. Other options at nearby airfields are currently being studied.

Despite the delays caused by the change in project leadership, some customers remain eager to get their hands on the first examples. Scott says the company holds in excess of 50 letters of interest for the aircraft from private individuals, operators and also governments. Agusta Westland is firmly aiming the aircraft at the commercial market. Contractual restrictions set by Bell mean the AW609 will never be allowed to carry any weaponry, but military use for long-range search and rescue, utility and transport is not out of the question. The company has completed a mock-up of the AW609 fuselage in a search-and-rescue configuration with a hoist installed on the upper section of the aircraft's main entry door.