AW609 tiltrotor prototype AC1 arrived at the Leonardo-Finmeccanica Philadelphia plant yesterday after recently resuming flight testing in Arlington, Texas. The AW609 flight-test program had been voluntarily halted following the fatal October 2015 crash of AC2 in Italy.

Plans call for AC1 to be be based out of Philadelphia, before being shipped to Italy for updates and modifications. The AW609, slated to be certified by the FAA, will be built in Philadelphia.
In May, Italian prosecutors impounded AC3 before it could make its first flight as part of their manslaughter probe into the AC2 crash. That aircraft was released by prosecutors last month and is expected to be shipped to the U.S. to join the flight-test program in Philadelphia, wher AC4 is currently being assembled and readied for first flight in 2017.
Despite the 10-month delay in the flight-test program, as well as calls for wind tunnel retesting and redesign of the fly-by-wire flight control system by Italian ANSV aviation investigators, the company insists that the AW609 remains on track for certification in 2018.