A major factor in reducing the pilot's workload is the cursor control device (CCD), a raised housing containing a roller ball sitting toward the front of the center console. Each pilot has a CCD, and uses the trackball to move a cursor around the display screens. The pilot can rest his hand on the housing to provide stability in flight, then use his fingers to move the cursor wherever he wants on the MFD or PFD. Once the cursor is positioned, a button is pushed and the command inputted, just like a left or right click with a mouse.
Also new to the S-76D is the installation of a United Technologies Aerospace Systems (formerly Goodrich) Vigor health and usage monitoring system (HUMS) as a baseline item. This feeds information on the drivetrain and other components to Sikorsky's Fleet Management Operations Center, where usage is monitored and analyzed for trends and exceedances to drive maintenance. Hunter says the HUMS comes from the S-92 program, where it has allowed operators to go to 9,400 hr. between overhauls, from 4,700 hr., on the swashplate alone.
The D is also equipped with a Moog active vibration-suppression system, using force generators that measure the vibration frequencies and produce opposing forces to suppress the vibration. Operators can fit up to six of these force generators, although each one adds weight and cost. While each operator will determine how much vibration is acceptable to its mission, Hunter expects “three to four” force generators to be the average installation.
Active vibration suppression is one of only three systems on the aircraft that use AC power. The two others are windshield heat and the RIPS. All other systems are driven by a 28-volt DC electrical system developed by Sikorsky for the S-76D. Two AC generators for the RIPS are mounted on the engines for redundancy and because the system will be used only in cold weather when the engines have power to spare.
The D model has been designed to carry more fuel, which combined with the improved engines will provide greater range. But the added components, such as HUMS and vibration suppression, add weight, which reduce range, “and you never, ever want to deliver an aircraft with less range than its predecessor,” Hunter says. So Sikorsky plans to increase the maximum gross weight to 11,875 lb. this summer, from 11,700 lb. “That essentially will get us back on parity with the C++ across the spectrum,” he says.
Sikorsky offered Aviation Week an opportunity to fly the new S-76 shortly after it received certification, so I arrived at its West Palm Beach, Fla., test facility on a beautiful day in late November, a perfect day for flying, but a terrible day for a flight evaluation as winds were light at around 17 kt., temperature was 78F, altitude was a mere 20 ft. and the aircraft weighed in at 9,494 lb., well below its 11,700-lb. maximum.
With twin PW210S engines producing 1,077 shp each, pushing the aircraft to its limits was unlikely. But what I really wanted to experience was just how much the pilot's workload was reduced by the new Thales TopDeck cockpit—and an hour's flight with Greg Barnes, project pilot for the S-76D program, more than met the need.
The initial part of the demonstration flight in aircraft N767J was fairly standard, with me sitting in the right seat and Barnes in the left. Start-up was the easiest I can remember in a helicopter. Power is controlled by two overhead “T”-shaped throttles, each with a start button at the end of one arm of the T. Push the button, the engine starts. Push the throttle forward and you have full power. The power can be applied slowly, in stages, or in one quick thrust—the pilot's choice. You probably would not want to make it one quick thrust on an icy helipad.
Taxiing from the helipad to the runway was basically as in any wheeled helicopter—put in a little power, push the cyclic forward a bit to get it started, then steer with the pedals while using just a bit of cyclic pitch input during a turn to keep the aircraft level. We taxied out to the active runway, where Barnes started by showing me that the D can do a 360-deg. turn around its own axis.