According to Stratford, Conn.-based Sikorsky, two more S-76D prototypes will soon join the helicopter test program, which is expected to conclude next year with certification and first deliveries. Meanwhile, the company said last week at the Paris Air Show that it is continuing envelope expansion on the first prototype, dubbed D1, which has been flying since February 7. Since then, milestones reached by the aircraft include raising the landing gear, flying at various speeds, conducting maneuvers and flying with different loads as test pilots study the prototype’s performance. As of late last month, the aircraft had achieved forward flight at 120 knots and 25-degree-bank turns. The testing has also verified the performance and vibration characteristics of the new main rotor blades, which have flown to 155 knots on a flight-test S-76C, Sikorsky said. “We are getting ready to transition to a full ‘D’ aircraft with all components, so the program is truly reaching a new peak in terms of testing the boundaries of what this aircraft can do,” said S-76D program manager Jason Durno. Aero Vodochody in the Czech Republic is currently building the first production aircraft, for delivery to Sikorsky later this year.