Sikorsky Continues To Expand S-76D’s Flight Envelope

The new Sikorsky S-76D medium twin recently performed high-altitude takeoff and landing tests at Colorado’s Lake County Airport, the helicopter manufacturer announced last week. The trials, which took place at almost 10,000 feet msl, were part of a so-called envelope-expansion program.

The Pratt & Whitney Canada PW210S-powered helicopter showed a significant improvement in its handling qualities in the Cat B envelope, compared with the legacy S-76 model, according to Sikorsky. In the Cat B envelope, an engine failure may result in an unscheduled landing, so engine failures were thus simulated during takeoffs and landings.

Testing also included autorotation flares with power recoveries at the helicopter’s 11,875-pound mtow. Finally, the high-altitude effort involved low-speed handling qualities and controllability testing at up to 35 knots in all directions. Malfunctions of the autopilot were included.

Separately, the S-76D has undergone high-intensity radiated field protection testing at the Naval Air Warfare Center Aircraft Division in Patuxent River, Md. The latest iteration of the medium twin received a “baseline” certification last October but the first delivery, originally scheduled for last month, has not happened yet.