Sikorsky SH-3 Sea King

The Sikorsky SH-3 Sea King (company designation S-61) is an American twin-engined anti-submarine warfare (ASW) helicopter designed and built by Sikorsky Aircraft. It was a landmark design, being the first ASW helicopter to take advantage of turboshaft engines, as well as being the first amphibious helicopter in the world. Introduced in 1961, it served with the United States Navy, and remains in service in many countries around the world. The Sea King has been built under license in Italy and Japan, and in the United Kingdom as the Westland Sea King. The major civil versions are the S-61L and S-61N.

Origins
As the Cold War between the US and the Soviet Union developed, the Soviet Navy had elected to construct a large fleet of over 200 submarines, the US Navy chose to counter this threat by investing in newer and increasingly capable ASW technologies and platforms such as the Sea King. In 1957, Sikorsky was awarded a contract to develop an all-weather amphibious helicopter for the U.S. Navy. The new helicopter would excel at anti-submarine warfare (ASW) and would combine the roles of hunter and killer, previously these had to be performed by two separate helicopters. The key features of the emerging ASW helicopter would include its amphibious hull for landing on the water, and its twin-turboshaft engines that enabled a larger, heavier and better-equipped aircraft than prior helicopters.



The first prototype took flight for the first time in March 1959. Carrier suitability trials were conducted on board the USS Lake Champlain; the trials were completed successfully in mid-1961. Production deliveries of the HSS-2 (later designated SH-3A) to the US Navy began in September 1961, these initial production aircraft were each powered by a pair of General Electric T58 turboshaft engines.

Sikorsky also developed a variant of the Sea King for the civil market, designated Sikorsky S-61L. The first operator of the S-61L was Los Angeles Airways, who introduced them to service on 11 March 1962. Another variant with a conventional hull, the Sikorsky S-61R, was also concurrently developed for transport and search and rescue (SAR) duties, this type was extensively operated by the U.S. Air Force and the U.S. Coast Guard.

In late 1961 and early 1962, a modified U.S. Navy HSS-2 Sea King was used to break the FAI 3 km, 100 km, 500 km and 1000 km helicopter speed records. This series of flights culminated on 5 February 1962 with the HSS-2 setting an absolute helicopter speed record of 210.6 mph. This record was broken by a modified Sud Super Frelon helicopter on 23 July 1963 with a speed of 217.7 mph.

Further developments
In the early 21st century, following their drawdown in US service, there has been multiple initiatives to refurbish ex-military Sea Kings for continued operations; in addition to civil operators, nations such as Egypt and India acquired refurbished Sea Kings to supplement their own aging fleets. While Sikorsky formally ended production of the helicopter model in the 1970s, in 2009, it was reported that nearly 600 Sea Kings were in operational service.

Design
When introduced, the Sea King was a considerable advancement over previous helicopters; its twin-turboshaft powerplant layout gave the SH-3 a payload capacity and level of reliability far in excess of previous anti-submarine helicopters. In the event of an engine failure, the Sea King can maintain flight on a single engine alone. Sea Kings operating in an anti-submarine capacity typically had a four man crew; a pilot and copilot in the cockpit and two aircrew in the cabin area to operate and monitor the aircraft's detection equipment and to interpret the sensor data; the two rear aircrew were retained in other mission roles such as cargo transfer and rescue operations. The cabin can accommodate up to 22 survivors or nine stretchers in addition to two medical officers in a SAR capacity; up to 28 soldiers can be accommodated when operated as a troop transport.

The Sea King features many design elements to support naval-orientated operations; the main rotor blades and the tail section could be folded for storage when deployed onboard ships. An amphibious hull allows most Sea Kings to land on and remain on the ocean's surface as a matter of operational routine; for stability and increased flotation, the aircraft's sponsons contain deployable airbags for use when the Sea King planned to come into direct contact with the sea.

Depending upon their intended mission, the armament fitted upon a Sea King could vary considerably. A typical armament configuration in an anti-submarine capacity could include up to four torpedoes or four depth charges. For anti-ship duties some models were outfitted to carry one or two missiles, typically Sea Eagles or Exocets. The Sea King had also the option of being outfitted to deploy the B57 nuclear bomb.

ASW equipment used onboard Sea Kings has included the AQS-13A/B/E dipping sonar, specialised computers for processing sonar and sonobuoy data, various models of sonobuoys, ARR-75 Sonobuoy Receivers, and Magnetic Anomaly Detectors. The commonly-fitted AKT-22 data link enabled the rapid dissemination of gathered sonar information to other friendly elements in range. Some later Sea King models featured digital navigation systems and overhauled cockpit instrumentation for night vision compatibility.

Operational history


The Sea King became operational with the United States Navy in June 1961 as the HSS-2; the aircraft's designation subsequently changed to SH-3A when the unified aircraft designation system was introduced. It was used primarily for anti-submarine warfare, detecting and tracking Soviet submarines and, in time of war, would be used to attack enemy submarines as well. Night-time ASW operations were possible, with considerable difficulty. The Sea King was widely exported, particularly for its anti-submarine capabilities, and was operated in large numbers by several nations, including Brazil, Italy, Japan and the United Kingdom.

The Sea King also performed various other roles and missions such as search and rescue, transport, anti-shipping and airborne early warning operations. Aircraft carriers would typically deploy Sea Kings to operate in the close vicinity of the carrier in order to act as a plane guard, ready to respond to another aircraft that crashed during takeoff or landing. Providing a safety margin for other operations, and transferring personnel and mail in between vessels were routine, if less prestigious, duties for the US Navy Sea Kings.

During the Vietnam War, SH-3s were used to rescue the crews of downed aircraft both at sea and over land; the Sea Kings were regularly tasked with retrieval operations in hostile territory were outfitted with self-sealing fuel tanks, machine guns and armor. The Sea King has significantly useful for medical evacuations and disaster relief efforts throughout its service life.



The SH-3 became the primary helicopter for the retrieval of manned space capsules, starting with the recovery of Mercury-Atlas 7 in May 1962. In February 1971, a SH-3A, operating from the amphibious assault ship USS New Orleans, performed the recovery mission of Apollo 14. A specialist search and rescue variant of the SH-3, the HH-3, also performed in this capacity.

Several Sea Kings, operated by the United States Marine Corps's HMX-1 unit, are used as the official helicopters of the President of the United States; in this capacity, the call sign 'Marine One' is used by the helicopter currently occupied by the President. As of 2012, a replacement helicopter fleet for the Sea King is pending under ongoing the VXX program.

In 1992, the US Justice Department sued Sikorsky over allegations of overcharged component pricing and deliberately misleading US Navy negotiators. In 1997, the Justice Department accused Sikorsky of willful overchanging on a contract to upgrade the Navy's Sea Kings.

During the 1990s, the Sea King was replaced in the ASW and SAR roles by the U.S. Navy with the newer Sikorsky SH-60 Sea Hawk. However, the SH-3 continued to operate in reserve units in roles including logistical support, search and rescue, and transport. On 27 January 2006, the SH-3 was ceremonially retired at NAS Norfolk, Virginia, by Helicopter Combat Support Squadron 2 (HC-2). They have been replaced by increasingly advanced variants of the SH-60 Sea Hawk.

US military

 * XHSS-2: The only prototype of the H-3 Sea King.
 * YHSS-2: Pre-production S-61 aircraft, seven built for the U.S. Navy, re-designated YSH-3A in 1962.
 * SH-3A : Anti-submarine warfare helicopter for the U.S. Navy; 245 built. Originally designated HSS-2.
 * HH-3A: Combat search and rescue helicopter for the U.S. Navy. 12 converted from SH-3A.
 * CH-3A: Military transport version for the U.S. Air Force; three converted from SH-3As into CH-3A configuration; they later became CH-3Bs.
 * NH-3A (S-61F): Experimental high speed compound helicopter, with extensive streamlining, no floats, short wings carrying two turbojet engines for extra speed; one converted from SH-3A. Later modified with a tail rotor able to rotate 90° to serve as a pusher propeller; this helicopter demonstrated "Roto-Prop" pusher propeller for Sikorsky's S-66 design.
 * RH-3A: Minesweeper helicopter for the U.S. Navy. Nine converted from SH-3A aircraft.
 * VH-3A: VIP transport helicopter for the U.S. Army and Marine Corps; originally designated HSS-2Z. Eight built, plus two SH-3A (STAKE) conversions rebuilt from damaged helicopters (one YHSS-2 and one SH-3A).  One (Army operated) was given to Egypt in 1972 and one (also Army operated) crashed at Walker Key, Bahamas in 1973.  The rest were returned to the U.S. Navy (HC-6) in 1975–76 and replaced by the VH-3D.  At least two have subsequently been placed in museums.
 * CH-3B: Military transport helicopter for the U.S. Air Force.
 * SH-3D (S-61B, HSS-2A): Anti-submarine warfare helicopter for the U.S. Navy. 73 built and two conversions from SH-3As.
 * VH-3D: VIP transport helicopter for the U.S. Marine Corps. It entered service in 1976.
 * SH-3G: Cargo, utility transport helicopter for the U.S. Navy. 105 conversions from SH-3A and SH-3D.
 * SH-3H (HSS-2B): Upgrade of the SH-3G as an anti-submarine warfare (ASW) helicopter for the U.S. Navy. It included SH-3G features with improvements for ASW, anti-ship missile detection and other airframe improvements.  163 SH-3Gs were upgraded to SH-3H configuration.
 * SH-3H AEW: Airborne early warning version for the Spanish navy.
 * UH-3H: Cargo, utility transport version for the U.S. Navy; converted from SH-3H by removing ASW systems.

Sikorsky designations

 * S-61: Company designation for the Sea King.
 * S-61A: Export version for the Royal Norwegian Air Force equipped for search and rescue role with anti-submarine warfare hardware removed.
 * S-61A-4 Nuri: Military transport, search and rescue helicopter for the Royal Malaysian Air Force. It can seat up to 31 combat troops. 38 built.
 * S-61A/AH: Utility helicopter for survey work and search and rescue in the Antarctic.
 * S-61B: Export version of the SH-3 anti-submarine warfare helicopter for the Japanese Maritime Self Defense Force.
 * S-61D-3: Export version for the Brazilian Navy.
 * S-61D-4: Export version for the Argentine Navy.
 * S-61NR: Search and rescue version for the Argentine Air Force.
 * S-61V: Company designation for the VH-3A. One built for Indonesia.


 * S-61L/N:


 * Civil versions of the Sea King.


 * S-61R:


 * The S-61R served in the United States Air Force as the CH-3C/E Sea King and the HH-3E Jolly Green Giant, and with the United States Coast Guard and the Italian Air Force as the HH-3F Sea King (more commonly referred to by the nickname "Pelican").

United Aircraft of Canada



 * CH-124: Anti-submarine warfare helicopter for the Royal Canadian Navy (41 assembled by United Aircraft of Canada).
 * CH-124A: The Sea King Improvement Program (SKIP) added modernized avionics as well as improved safety features.
 * CH-124B: Alternate version of the CH-124A without a dipping sonar but formerly with a MAD sensor and additional storage for deployable stores. In 2006, the five aircraft of this variant were converted to support the Standing Contingency Task Force (SCTF), and were modified with additional troop seats, and frequency agile radios. Plans to add fast-rope capability, EAPSNIPS (Engine Air Particle Separator / Snow & Ice Particle Separator) did not come to fruition.
 * CH-124B2: Six CH-124B's were upgraded to the CH-124B2 standard in 1991–1992. The revised CH-124B2 retained the sonobuoy processing gear to passively detect submarines but, the aircraft was now also fitted with a towed-array sonar to supplement the ship's sonar. Since anti-submarine warfare is no longer a major priority within the Canadian Forces, the CH-124B2 were refitted again to become improvised troop carriers for the newly formed Standing Contingency Task Force.
 * CH-124C: One CH-124 operated by the Helicopter Operational Test and Evaluation Facility located at CFB Shearwater. Used for testing new gear, and when not testing new gear, it is deployable to any Canadian Forces ship requiring a helicopter.
 * CH-124U: Unofficial designation for four CH-124s that were modified for passenger/freight transport. One crashed in 1973, and the survivors were later refitted to become CH-124A's.

Westland


The Westland Sea King variant was manufactured under license by Westland Helicopters Ltd in the United Kingdom, who developed a specially modified version for the Royal Navy. It is powered by a pair of Rolls-Royce Gnome turbines (license-built T58s), and has British avionics and ASW equipment. This variant first flew in 1969, and entered service the next year. It is also used by the Royal Air Force in a search and rescue capacity, and has been sold to many countries around the world.

Agusta

 * AS-61: Company designation for the H-3 Sea King built under license in Italy by Agusta.
 * AS-61A-1: Italian export model for the Royal Malaysian Air Force.
 * AS-61A-4: Military transport, search and rescue helicopter.
 * AS-61N-1 Silver: License built model of the S-61N, with a shortened cabin.
 * AS-61VIP: VIP transport helicopter.
 * ASH-3A (SH-3G): Utility transport helicopter
 * ASH-3D: Anti-submarine warfare helicopter. Flown by the Italian, Brazilian, Iranian, Peruvian and Argentinian navies.
 * ASH-3TS: VIP, executive transport mission helicopter. Also known as the ASH-3D/TS.
 * ASH-3H : Anti-submarine warfare helicopter.

Mitsubishi

 * S-61A: License-built version of the S-61A as Search-and-Rescue and Utility helicopters for the Japan Maritime Self Defense Force. 18 built.
 * HSS-2: License-built version of the S-61B as an Anti-submarine warfare helicopter for the Japan Maritime Self Defense Force. 55 built.
 * HSS-2A: License-built version of the S-61B(SH-3D) as an Anti-submarine warfare helicopter for the Japan Maritime Self Defense Force. 28 built.
 * HSS-2B: License-built version of the S-61B(SH-3H) as an Anti-submarine warfare helicopter for the Japan Maritime Self Defense Force. 23 built.

Operators

 * Argentine Naval Aviation
 * Brazilian Navy
 * Royal Canadian Air Force (See: CH-124 Sea King)
 * Indian Navy
 * Islamic Republic of Iran Navy
 * Italian Navy
 * Peruvian Navy
 * Spanish Navy
 * United States Marine Corps
 * HMX-1
 * Italian Navy
 * Peruvian Navy
 * Spanish Navy
 * United States Marine Corps
 * HMX-1
 * Spanish Navy
 * United States Marine Corps
 * HMX-1
 * HMX-1

Former operators

 * Royal Canadian Navy
 * Royal Danish Air Force
 * Japan Maritime Self Defense Force
 * Iraqi Air Force
 * Royal Saudi Air Force
 * United States Navy
 * Los Angeles County Sheriff's Department
 * Iraqi Air Force
 * Royal Saudi Air Force
 * United States Navy
 * Los Angeles County Sheriff's Department
 * United States Navy
 * Los Angeles County Sheriff's Department

Aircraft on display

 * SH-3G, BuNo 149932, display aboard USS Yorktown (CV-10), Patriot's Point Naval and Maritime Museum, Charleston, South Carolina.
 * SH-3H, BuNo 149695, permanent static display, NAS Jacksonville, Florida.
 * SH-3H, BuNo 148042, permanent static display, NS Norfolk/Chambers Field (formerly NAS Norfolk), Virginia adjacent to Gate #4
 * SH-3H, BuNo 149738, Quonset Air Museum, Quonset State Airport (former NAS Quonset Point), North Kingston, Rhode Island.
 * UH-3H, BuNo 149711, display aboard USS Midway (CV-41) Museum, San Diego, California.
 * VH-3A, BuNo 150613, National Museum of Naval Aviation, NAS Pensacola, Florida.
 * VH-3A, BuNo 150611, Ronald Reagan Presidential Library, Simi Valley, California.
 * VH-3A, BuNo 150617, Richard Nixon Presidential Library and Museum, Yorba Linda, California.
 * UH-3H Sea King on display at Evergreen Aviation & Space Museum, McMinnville, Oregon. Painted as Apollo 11 recovery helicopter.
 * S-61A, 61-240, static display at Danmarks Flymuseeum, Stauning, Denmark.