Sikorsky Aircraft has initiated the first elements of a mucn anticipated S-76 model upgrade, designed to provide even higher levels of performance and reliability for the company's flagship commercial aircraft. The improvements are targeted for delivery in 2005.

The new S-76 aircraft will include Turbomeca Arriel 2S2 engines, boasting six percent more power than the current Arriel 2S1 engine and offering a dual channel digital engine control. The 2S2 will combine improved hot-high performance with a simpler and more reliable control system. Sikorsky and Turbomeca signed the formal agreement to develop and certify the Arriel 2S2 for the S-76 in November 2002.

Additional features for the S-76 model upgrade include the S-76 Quiet Tail Rotor, new proprietary quiet gearbox technology and rotor de-ice capability, which is derived from the system designed for the recently-certified Sikorsky S-92. All model upgrade improvements will retrofit the S-76C+, and some elements will be available to the S-76B and S-76A versions.

"We constantly identify opportunities to keep the S-76 the most modern aircraft in its class," said Tommy Thomason, Vice President-Civil Programs. "The improvements planned for future S-76 production should also be available to the customers who have purchased previous versions of the S-76."
While progress is underway on the model upgrade, simultaneous work is on track to further enhance the state-of-the-art safety, reliability and maintainability of the existing S-76 fleet.

In 2002, the commitment to S-76 improvement yielded the following:

• A solid construction servo input rod that reduces maintenance;
• A new procedure allowing customer replacement of the swashplate uniball bearing shim;
• Fuzz burn chip detectors for the Arriel 2S1 engines;
• 2,000 hour tail rotor retention plate life increase.

"Operator data directs our S-76 improvements, so we are confident that the benefit to the customer is real," said Thomason. The diverse reliability and maintainability improvements being fielded in 2003 include:

• Field-replaceable main gearbox upper main rotor shaft seal;
• Improved corrosion resistance of the landing gear;
• "Smart contactor" design to preserve correct electrical system switching
• New engine vent line that improves Arriel breathing while reducing leakage and oil consumption;
• Increased life for the tail rotor horn;
• Enhanced Mark XXII EGPWS for better GPS reception, in conjunction with Honeywell.

Customer feedback through the operator-led Maintenance Review Steering Group (MRSG) directs Sikorsky's priority list for product improvements, thereby ensuring continued reliable operation of even the earliest S-76 versions. The MRSG is composed of customers representing the spectrum of S-76 applications and worldwide environments dedicated to tailoring the maintenance requirements as the fleet matures and expands into new markets and missions. Operating in 44 countries by 192 operators, more than 530 Sikorsky S-76 helicopters have accumulated over 3 million flight hours.

FMI: www.sikorsky.com