mandates. This move effectively ended production of the S-76 following the completion of the three orders that were outstanding, and represented a withdrawal by Sikorsky from the medium commercial helicopter market. Sikorsky has stated that it will continue to actively manufacture spare parts for the S-76 at its Connecticut facility. Design The S-76 is of a conventional configuration, with a four-bladed fully articulated main rotor and a four-bladed anti-torque rotor on the port side of the tailboom. It is powered by a pair of turboshaft engines, which are located above the passenger cabin. On the prototypes and initial production aircraft, these engines were Allison 250-C30s, a variant of the popular Allison 250 engine that was developed specially for the S-76l it had a single-stage centrifugal compressor instead of the multi-stage axial/centrifugal compressor of earlier models of the engine, rated at for takeoff. These engines are connected to the main rotor by the main gearbox, a three-stage unit with a bull gear as its final stage, rather than the planetary gear that had been used by previous generations of Sikorsky helicopters. This arrangement has 30% fewer parts and lower costs than a more conventional design. The main rotor is furnished with a single piece aluminum hub fitted with elastomeric bearings, which are designed not to require lubrication or any other kind of maintenance throughout its design life. The main rotor blades have titanium spars and incorporate a ten degree twist to provide an even loading when hovering, while they use a non-symmetrical airfoil section with a drooped leading edge. The rotor tips are tapered and swept back. The rotor blades on later-build S-76s feature ice protection measures. The flight controls are servo-assisted and have a Stability Augmentation System fitted. A retractable nosewheel undercarriage is fitted, the reduced drag from this arrangement is credited with increasing the S-76A's cruising speed by . Emergency flotation gear can be fitted, which uses helium-filled bags to increase buoyancy in the event of a forced landing on water. The fuselage of the S-76 is made from both metal and composite materials; while the nose is composed of fiberglass, the cabin area primarily employs a light alloy honeycomb structure, the semi-monocoque tailboom is also constructed of light alloy. A pair of pilots are typically seated in a side-by-side arrangement in the cockpit, situated ahead of the cabin, which can accommodate a further 12 passengers in three rows