Sikorsky S-76 Helicopter

Sikorsky S-76 is a multi-role, medium-size utility helicopter manufactured by Sikorsky Aircraft, a subsidiary of Sikorsky Aircraft. It was principally designed and developed for CHC Helicopter Corporation, Canada. The maiden flight of S-76 took place on 13 March 1977. More than 800 S-76 helicopters have been delivered to various operators worldwide.

Operations carried out by the S-76 include executive passenger transport (VIP), emergency medical services (EMS), search-and-rescue operations (SAR) and offshore passenger and material transportation. The S-76 can accommodate 14 people including two pilots. It has a retractable landing gear.

Sikorsky Aircraft Corporation received Federal Aviation Administration (FAA) certification for its S-76C++, a variant of the S-76, in January 2006.

In October 2012, the FAA issued the Type Certificate for S-76D helicopter, the newest variant of S-76. The first S-76D helicopter was delivered in the last quarter of 2013.

In April 2014, the Civil Aviation Administration of China (CAAC) issued a validation type certificate for the S-76D helicopter.

S-76 variants

The S-76 is available in ten variants: S-76A, S-76A Utility, S-76A+, S-76A++, S-76A Mk II, S-76B, S-76C, S-76C+, S-76C++ and S-76D.

The S-76A is the first model in the S-76 series. About 284 S-76A helicopters have been manufactured. The second variant, the S-76A Utility, is an advanced version of the S-76A. The S-76A Utility is fitted with sliding doors and a strengthened floor.

The S-76A+ variant has two Turbomeca Arriel 1S turbo shaft engines. An all-weather transport model, the S-76A Mk II variant was derived from the S-76A+ by equipping the latter helicopter with powerful engines.

S-76Bs were equipped with two Pratt and Whitney PT6B-36A or PT6B-36B turbo shaft engines. An upgrade of the power capacity of the engines to 539kW led to the development of the S-76C.

Another variant, S-76C+, was developed by upgrading the S-76B engine with full-authority digital engine controls (FADEC). The S-76C+ is powered by enhanced Arriel 2S1 turboshafts.

Another new variant, S-76C++, was developed by overhauling the engines, avionics and new gearboxes of the S-76C. The presence of powerful engines in the S-76C++ increased the takeoff weight by 450lbs. The S-76C++ also includes a new cabin for VIP transport.

Orders and deliveries

Offshore Logistics Inc (OLOG) procured 35 S-76 helicopters and also purchased rights for an additional 24 S-76s on 14 June 2005.

Two S-76 helicopters were acquired by China Eastern General Aviation Corporation (EGAC) on 1 August 2005 to affirm oil offshore operations in the Bohai Bay area of northern china.

On 27 October 2005 JC Bamford Excavators bought an S-76C++ helicopter. US Helicopter Corporation procured an order for four S-76C++ helicopters from Sikorsky on 27 February 2006. Sikorsky also received an order for three new-build S-76C++ helicopters from Malaysian Helicopter Service (MHS) on 29 June 2006.

Two S-76C++ helicopters were acquired by Macau-based Wynn Resorts on 17 October 2006. Aero Med Spectrum Health of Grand Rapids, Michigan bought an S-76C++ helicopter from Sikorsky Aircraft Corporation on 17 October 2006.

Sikorsky Aircraft Corporation signed a contract with Boston MedFlight to supply an S-76C++ helicopter for air medical transports. EraMed, LLC operates S-76C++ in place AS-365N2 Dauphin.

In November 2007 the Royal Household, UK awarded a contract to Sikorsky Aircraft Corporation to provide an S-76C++. It was delivered to the Royal Travel Office on November 2009.

In June 2011, SonAir Servico Aereo of Angola and Heli-Union of France took deliveries of six and two S-76C++ helicopters respectively.

In February 2012, Sikorsky received orders for the delivery of four S-76D helicopters from the Japan Coast Guard. Air Engiadina of Switzerland placed an order for one S-76D helicopter during the same month.

Sikorsky Aircraft and Chinese Ministry of Transport’s (MOT) Rescue and Salvage Bureau signed a contract for four Sikorsky S-76D search and rescue helicopters in March 2013. An option for four more helicopters was added in July 2013.

In March 2013, Bristow Group signed an agreement with Sikorsky for up to 26 S-76D helicopters. The first helicopter was delivered in December 2013.

Arkansas Children’s Hospital (ACH) placed a contract with Sikorsky for two S-76D helicopters in March 2013.

Mitsubishi Corporation placed an order for 11 S-76D helicopters for the Japan Coast Guard (JCG) in June 2013. The first helicopter was delivered in mid 2014.

Development

Sikorsky Aircraft Corporation commissioned the development of a medium business helicopter, UH-60 Black Hawk, in the 1970s. The company focused on airlines that were using medium business helicopters and the oil drilling industry. Sikorsky built the S-74, which was renamed the S-76 Spirit. The S-76 Spirit was equipped with two Allison 250 C30 turbo shafts with the capacity to generate 478kW of power each.

In 1982 the S-76A, also known as the S-76 Mk II, was developed. The S-76A provides high-range climbing. It is being operated by Helijet Airways of Vancouver, British Columbia, Canada.

In 1987 an advanced version, S-76B, was introduced. It can fly at speeds of 155k at sea level. About 500 S-76s were delivered by early 2001. Turbomeca Arriel 2S1 engines were deployed in the S-76C+ until December 2005. The main rotor of the S-76C+ was manufactured using composite material. Increased active noise and vibration dampers were used to provide more comfort for passengers. Production of the S-76C+ was completed in December 2005.

The S-76C++, which features an intake air filter and an improved and quieter transmission, was launched later. It is equipped with upgraded interior equipment and electronics. The production of S-76C++ was completed in January 2006. The helicopter is powered by a Turboméca Arriel 2S2 turbo shaft engine.

The S-76D is equipped with a Pratt and Whitney 210S engine. The dual FADEC-controlled engine can produce about 1,050shp of power. Active Vibration Control System (AVCS) and four-bladed composite main rotor are installed for smooth operation.

The revolutions per minute (rpm) of the rotor are self-adjusted. The higher rpm is applied during takeoff and lower rpm setting is applied for enhancing cruise range.

The maiden flight of S-76D took place in February 2009. The helicopter entered production phase in December 2009. Final assembly production started a year later in December 2010, with the first flight test of the second prototype complete in March 2010.

Cabin of S-76C aircraft

The S-76C++ helicopter has a large rectangular cabin. The length and width of the cabin are 2.41m and 1.93m respectively. The height and area of the cabin are 1.35m and 4.65m² respectively. The baggage volume and cabin volume are 1.08m³ and 5.78m³ respectively.

The helicopter also has a spacious cabin interior, an AVCS, reduced interior noise, two cabin doors with pop-out windows and two cockpit doors.

S-76C Cockpit

The cockpit is equipped with a Honeywell primus weather radar, dual comm / nav radios, an automatic direction finder, dual attitude and heading reference systems (AHRS) and air data computers, a radio altimeter, a mode C transponder, dual VORs with glideslope, distance measuring equipment (DME) and a cockpit voice recorder (CVR).

Avionics

The avionics suite installed in the cockpit of the S-76C++ includes a Honeywell four-tube electronic flight instrument system (EFIS), a four-axis fully coupled autopilot, an integrated instrument display system (IIDS) and a Honeywell enhanced ground proximity warning system (EGPWS).

The S-76D’s cockpit is fitted with an avionics suite that includes a Thales Top Deck avionics system, four-axis fully coupled autopilot, an EGPWS, a traffic collision avoidance system (TCAS1), a Honeywell Primus 660 weather radar, a health usage monitoring system (HUMS), a Thales digital map and a Collins Pro Line 21 comm / nav radio suite.

Engine

The S-76 is powered by two Turbomeca Arriel 2S2 turbo shaft engines. Each engine can produce a takeoff power of 688kW. The length and height of the engine are 1.156m and 0.6m respectively. The engine can generate maximum continuous power of 621kW.

The engine has simple design that consists of five modules. This provides simpler maintenance and reduces operating cost through optimised acceleration modes. The Arriel 2S2 turbo shaft engine produces 6% more power than the Arriel 2S1 turbo shaft engine. It is also equipped with a double-channel electronic engine control unit (EECU), which measures fuel, ignition timing and other parameters. The endurance of the Arriel 2S2 is 3,000h.

The Arriel 2S2 is suitable for helicopter carrying missions such as EMS, SAR, police, VIP, aerial work, corporate and off-shore liaison.

Performance

The S-76 can fly at a maximum speed of 287km/h. The ferry range and service ceiling of the helicopter are 639km and 4.572m respectively. The maximum takeoff weight of the S-76 is 5,306kg while the empty weight is 3,177kg.