Sikorsky announced yesterday that the third prototype of the S-76D medium-twin helicopter joined the test fleet, having made its first flight probably in July or August, AIN understands. Sikorsky had planned to reach this milestone early this year. “D3” will be used for avionics and electrical system certification. In conjunction with this announcement, yet another program delay has thus appeared for the S-76D–certification is now pegged for the first quarter of next year. Meanwhile, the first two test aircraft have logged more than 500 flight hours. An “indirect lightning test” was completed last month, demonstrating that “essential avionics and electrical equipment” are protected. The latest iteration of the S-76 features a dual-speed main rotor with a quiet mode, a digital four-axis autopilot and Thales TopDeck avionics. The Pratt & Whitney Canada PW210S turboshafts give the helicopter 14 percent more takeoff power and 8 percent better fuel efficiency over its predecessor. Some customers have been given the opportunity to fly in the test aircraft.