The fortunes of the Bell/Agusta BA609 are closely linked to those of the U.S. Marines’ MV-22 Osprey tiltrotor transport, still grounded following a pair of well-publicized fatal accidents and even more sensational charges of records falsification and related wrongdoing by senior Marine program managers. In a recent interview, undersecretary of defense Pete Aldridge said he doubted the Marines’ remaining fleet of eight Ospreys would return to flight status before the end of the year.

Bell and program partner Agusta wanted to get their BA609 prototype airborne before the end of the year but have admitted to delays. Work on the first and second prototype BA609s is now proceeding in the same Bell Helicopter hangars from which the first prototype V-22 Ospreys rolled out some 13 years ago in Arlington, Texas, and while the Marines’MV-22 has suffered through an agonizing, sometimes tragic decade-and-change of design, redesign, modification, cancellation and resurrection, the Bell/Agusta BA609 has had smoother sailing so far.

The first BA609 had its Pratt & Whitney Canada PT6C-67A engines installed in mid-July, with ground runups set to begin early next month and first flight expected to slip into January.

Systems testing of the first BA609, especially of its Rockwell Collins Pro Line 21 avionics, is ongoing. Early summer saw shipment to Bell of the BA609’s flight control software from BAE Systems in Santa Monica, Calif. (Among the honors of being the first production civil tiltrotor and the first production pressurized rotorcraft, the BA609 will also be the world’s first fly-by-wire general aviation aircraft.)

The basic fuselage of the second prototype is nearly complete. Upon completion, it will be used for mandatory proof-loads testing of the cockpit and prop-rotor structure. The aeroelastic stability of the wing and tilting nacelles will also be evaluated using this aircraft.

An Airplane or a Helicopter?

All of these tests are required by the FAA, which, like Agusta and Bell, is breaking ground in the BA609 certification process by combining relevant elements of FAR Part 25 (airworthiness requirements for transport category airplanes) with rules from Part 29 (airworthiness requirements for rotorcraft). The unique nature of tiltrotor technology (is it an airplane or a helicopter?) provides aeronautical certification authorities with a “neither fish nor fowl” conundrum.

To smooth the BA609’s path to international acceptance, Bell some time ago applied to Europe’s Joint Aviation Authorities (JAA) for certification of the civil tiltrotor. However, daunted by the JAA process, Bell has since withdrawn that application, opting instead for certification in non-U.S. nations on a case-by-case basis. (This money-saving move is likely driven by the fact that the bulk of BA609 sales have come from U.S. buyers.)

Future operators of the BA609 in the U.S. and elsewhere will be both cheered and sobered by the first flight of a production-configured civil tiltrotor aircraft late this year, for when that first BA609’s wheels clear the tarmac, the first payment on the roughly $10 million aircraft, set at 25 percent of the purchase price, will be due.

Bell maintains that while there has been some order turnover in recent months, prompted by a combination of the ongoing economic downturn and uncertainties over tiltrotor technology raised by the well-publicized problems with the U.S. Marines’ MV-22 Osprey program, new orders have arisen to replace those lost. Total backlog for the Osprey stands at “more than 80,” according to Donald Barbour, Bell/Agusta Aerospace marketing director.

In its nine-passenger initial configuration (there is talk of later, stretched, higher-capacity editions of the BA609) the world’s first civil tiltrotor is designed to be a 16,800-lb-mtow aircraft with a 5,500-lb useful load and enough power to perform Category-A operations at its maximum weight. That payload will be transported over a no-fuel-reserve range of 750 nm with a designed cruise speed (airplane mode) of 275 kt. With an operational ceiling of 25,000 ft, the BA609 will be the world’s first commercial pressurized production rotorcraft, with a cabin designed to a cruise pressure differential of 5.5 psi (The MV-22 is also pressurized).

A total of four BA609 test items are planned, with one of them intended as a static and fatigue test article. That series of tests, aimed at putting the airframe through the equivalent of 40,000 flight hours, will begin this month and is scheduled to conclude in 2003.

Not all of the flight tests will be in Texas. Under the terms of the Bell/Agusta agreement, half of that work will take place at Agusta’s Cascina Costa, Italy plant, where Agusta will have two of the prototype BA609s. Assuming all goes well, FAA certification will be granted in December 2003, with launch customer deliveries beginning a month later.

Ironically, if the convention had gone as scheduled last month, attendees would not have seen the BA609 mockup because it was in Duxford, England, for Helitech 2001 (September 25 to 28). With NBAA 2001 now scheduled for December, the mockup just might make the show.