Sikorsky S-61T

Modernised and converted from the decommissioned legacy aircraft, the Sikorsky S-61T helicopter is a civil variant of the popular SH-3 Sea King series. Known as an industry stalwart for more than five decades, the aircraft has been trusted by the US Navy, Air Force, Marine Corps and Coast Guard, as well as numerous international militaries.

Originally developed in 1959 by Sikorsky as an anti-submarine warfare helicopter for the US Navy, it first flew in November 1961. Since then, more than 1,400 of these helicopters have been produced for a large variety of both commercial and military missions.

The upgrade programme transforms Sikorsky’s original S-61 helicopter into a variety of mission specific applications such as search-and-rescue, firefighting, troop transport, external lift and homeland security.

Key upgrades include composite main rotor blades, a state-of-the-art glass cockpit and modular wiring harness, which all increase the aircraft’s performance, robustness and reliability. These improvements offer increased payload, as well as reduced pilot fatigue and aircraft maintenance, increasing overall safety.

The modernised S-61T can be outfitted to meet a wide variety of requirements and is boasted of providing best-in-class value for a mid-size, multi-mission helicopter.

The S-61T helicopter modernisation and conversion programme was launched in 2010, and is jointly managed by Sikorsky Aircraft Corporation and Carson Helicopters.

The US Department of State (DoS) signed a five-year indefinite-delivery indefinite-quantity (IDIQ) agreement in 2010 with Sikorsky to purchase up to 110 refurbished and modernised S-61aircraft.

Orders and deliveries of S-61T helicopter

The first two modernised S-61helicopters were delivered to the DoS in December 2010 in support of the US Embassy’s missions in Afghanistan. Sikorsky has so far delivered 16 modernised S-61aircraft to the DoS.

Its first flight test with an integrated glass cockpit and enhanced performance capabilities was completed in November 2013. The DoS’s latest order includes 13 S-61T helicopters for use in worldwide passenger and cargo transport missions. Completion of the deliveries is expected by the end of 2014.

Design features of Sikorsky S-61T

"The helicopter is equipped with defensive systems for use in dangerous areas, and features a 6,000lb. capacity cargo hook."

The modernised S-61T helicopter features full structural refurbishment and overhaul of all major dynamic components.

The baseline S-61T incorporates a number of enhancements, including a refurbished airframe, overhauled dynamic components and new composite main rotor blades that provide additional lift capability. Key upgrades also include fixed undercarriage for reduced weight and maintenance, and a survivability suite.

In addition, the modernised S-61T has a state-of-the-art glass cockpit and all new electrical wiring and is compliant with the latest design practices, and modern redundancy requirements are addressed throughout the aircraft.

The helicopter is equipped with defensive systems for use in dangerous areas, and features a 6,000lb. capacity cargo hook.

Cabin details

The helicopter cabin offers seating for 15 passengers and two crew members. The aircraft can be customised for command and control, medical evacuation, and quick reaction or other security force missions.

Cockpit and avionics of the modernised S-61T helicopter

"The helicopter features a fully modernised glass cockpit fitted with an advanced avionics suite that reduces the pilot workload."

The helicopter features a fully modernised glass cockpit fitted with an advanced avionics suite that reduces the pilot workload, enhances safety, and improves situational awareness.

This new cockpit comprises four 6in by 8in integrated display units with quadruple redundant flight management systems, moving maps, synthetic vision, and completely integrated engine instrumentation and crew alerting system (EICAS).

Other avionics features include automatic direction finding system, distance measuring system, integrated digital audio/radio management system, and aft-cabin audio control.

Engines and performance

The helicopter is powered by two GE T58-GE-402 engines and equipped with engine air particle separator (EAPs). The engines provide more external payload than short-fuselage version helicopters.

The helicopter can take off and land at 12,000ft above sea level. It has a maximum range of 480nm.

Defence Technology