Sikorsky Aircraft has begun delivering S-76 helicopters equipped as standard with a Parker Gull integrated instrument-display system (IIDS). Consisting of three liquid-crystal displays replacing the conventional engine and rotor instruments, the IIDS complements the Honeywell four-tube electronic flight-instrument system which has been standard in the S-76 for some time.

The system is the helicopter manufacturer's second attempt at installing a flat-panel IIDS in the S-76. The Rogerson-Kratos system selected originally has failed to meet reliability targets, but Sikorsky describes initial experience with the Parker Gull equipment as "terrific".

Mike Moran, director of commercial programmes, expects the new IIDS to achieve a mean time between unscheduled removals of "6,000-10,000h", compared with 700h for the original system.

The IIDS is the latest in a series of improvements to the S-76. Enhancements in the pipeline, Moran reveals, include a quiet tail-rotor, active noise and vibration control, an advanced health- and usage-monitoring system and composite rotor blades.

Sikorsky has standardised production on the S-76C+, which is powered by Turboméca Arriel 2S1s, and will deliver the 101st and final Pratt & Whitney Canada PT6B-powered S-76B in December. Previously, the B was produced alongside the Arriel-powered S-76C.

The S-76B was developed to provide improved single-engine performance for the corporate market, but the uprated and digitally controlled Arriel 2S1 gives the S-76C+ "a single-engine climb rate slightly better than that of the B", while retaining the longer range of the Arriel-powered S-76C, Moran says.

Sikorsky has completed flight testing of the quiet tail-rotor. This has four curved blades and "-substantially softens" the characteristic tail-rotor noise of the S-76, Moran says. A more-efficient aerofoil also allows tail-rotor speed to be reduced while producing the same thrust, requiring less power.

Source: Flight International