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Sikorsky SH-3 Sea King
Sikorsky SH-3 Sea King
Sikorsky SH-3 Sea King
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SH-3 Sea King dipping a sonar, 1983

Key Information

The Sikorsky SH-3 Sea King (company designation S-61) is an American twin-engine anti-submarine warfare (ASW) helicopter designed and built by Sikorsky Aircraft. A landmark design, it was one of the first ASW rotorcraft to use turboshaft engines.[1]

The Sea King has its origins in efforts by the United States Navy to counter the growing threat of Soviet submarines during the 1950s. Accordingly, the helicopter was specifically developed to deliver a capable ASW platform; in particular, it combined the roles of hunter and killer, which had previously been carried out by two separate helicopters. The Sea King was initially designated HSS-2, which was intended to imply a level of commonality to the earlier HSS-1; it was subsequently redesignated as the SH-3A during the early 1960s.

Introduced to service in 1961, it was operated by the United States Navy as a key ASW and utility asset for several decades prior to being replaced by the non-amphibious Sikorsky SH-60 Seahawk in the 1990s. 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. The Sea King also performed various other roles and missions such as search-and-rescue, transport, anti-shipping, medevac, plane guard, and airborne early warning operations.

The Sea King has also proved to be popular on the export market with foreign military customers, and has also been sold to civil operators as well. As of 2024, many examples of the type remain in service in nations around the world, although some major users have begun to retire the type. The Sea King has been built under license by Agusta in Italy, Mitsubishi in Japan, Canada by United Aircraft of Canada, and by Westland in the United Kingdom as the Westland Sea King. The major civil versions are the S-61L and S-61N. The S-61R was another important variant, which was the CH-3C/E Sea King, used by the U.S. Coast Guard as the HH-3F Pelican, and the Air Force's HH-3E Jolly Green Giant; this version had a ramp at the rear among other changes.

Development

[edit]

Origins

[edit]

During the Cold War, the Soviet Navy built up a large and varied fleet of submarines which at one point was in excess of 200 operational submarines. The US Navy countered this threat by the improvement and development of various anti-submarine warfare (ASW) capabilities, which resulted in the development of the Sea King.[2] During the late 1950s, the US Navy took advantage of recent aerospace advances, such as the turboshaft engine, by commissioning the development of a new large naval helicopter. Sikorsky received a request from the service to design a new turbine-powered helicopter that would be capable of performing the ASW mission. The specification included a dipping sonar, mission endurance of four hours, and the ability to support a weapons load of 380 kg (840 lb).[3]

XHSS-2 Sea King prototype

In 1957, Sikorsky was awarded a contract to produce an all-weather amphibious helicopter for the US Navy. As per the earlier specification, this new rotorcraft was to excel at ASW; specifically, it would combine the roles of hunter and killer, as these two duties had previously been carried out by two separate helicopters.[3][4] It was also the first helicopter to be procured under the US Navy's new weapon system concept, under which Sikorsky was responsible not only for the design and production of the airframe, but all major onboard systems, such as the sonar, navigational equipment, electronic devices, and support equipment. As such, the navigation suite for the rotorcraft was developed jointly by Sikorsky and the US Navy.[5]

Key features of the emerging ASW helicopter included its amphibious hull, which enabled the rotorcraft to readily perform water landings, and its adoption of a twin-turboshaft engine arrangement that enabled it to be larger, heavier and better-equipped than had been possible with prior helicopters.[4][5][6] The designation HSS-2 was applied, allegedly to imply a level of commonality to the earlier HSS-1, should political sentiment turn against the development of an entirely new rotorcraft.[3] A total of ten prototypes were produced to support the development program.[7]

Into flight

[edit]
SH-3As of HS-6 above Kearsarge in the early 1960s

On 11 March 1959, the first prototype conducted its maiden flight.[4] During early 1961, a pair of prototypes were stationed on board the aircraft carrier Lake Champlain to fulfill a demand for carrier suitability trials. These trials, which involved testing the folding mechanism of the main rotor blades and a series of takeoffs performed during winds of up to 50 mph (80 km/h), were completed successfully in mid-1961.[7][8] Shortly after the completion of suitability trials, the US Navy formally accepted delivery of the first HSS-2 rotorcraft, which was subsequently re-designated as the SH-3A, in September 1961.[9]

In late 1961 and early 1962, a modified US 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 (338.9 km/h).[10][11] This record was broken by a modified French Sud-Aviation Super Frelon helicopter on 23 July 1963 with a speed of 217.77 mph (350.47 km/h).[12]

Further developments

[edit]
SH-3A landing on the sea in 1964

The base design of the Sea King had proved sound and several aspects were judged to be potentially useful for other operators, thus Sikorsky elected to pursue the further development of the rotorcraft for other markets beyond the US Navy.[7] One of the major variants of the Sea King to be produced was a model for civil operators, which was designated as the Sikorsky S-61L. The first operator of the S-61L was Los Angeles Airways, who introduced the type to service on 11 March 1962.[13][14] Another noteworthy Sea King variant, the significant change this time being the adoption of a conventional fuselage, the Sikorsky S-61R, was also concurrently developed for transport and search and rescue (SAR) duties, this type being extensively operated by the U.S. Air Force and the U.S. Coast Guard.[15]

In U.S. Navy service, the initial SH-3A model of the Sea King would be progressively converted into the improved SH-3D and SH-3H variants; these featured more powerful engines and improved sensors that gave the type greater operational capabilities as an ASW platform. It was also common for Sea Kings to be converted for non-ASW activities, these roles included minesweeping, combat search and rescue, and as a cargo/passenger utility transport.[4] The aircrew on ASW-tasked Sea Kings were routinely trained to carry out these secondary roles as aircraft could often be quickly adapted to perform different missions in the face of operational needs.[16]

The NH-3A prototype, which tested outfitting a Sea King with fixed wings and jet engines

The NH-3A (S-61F) was an experimental high-speed compound helicopter based on the Sea King tested in the 1960s.[17] 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.[18]

A minesweeper version of the Sea King for the U.S. Navy was made, with nine converted from SH-3A aircraft and then called the RH-3A.[19]

In addition to those Sea Kings that were manufactured by Sikorsky, several license agreements were enacted with other firms to produce the type. These included the Japanese conglomerate Mitsubishi and the Italian aerospace company Agusta. Another licensee was the British helicopter manufacturer Westland Helicopters, which substantially redesigned the Sea King to produce various models of their own, collectively referred to as the Westland Sea King.[20][21][22] In contrast to the US Navy's Sea Kings, the Westland Sea King was intended for greater operational autonomy.[23] In total, Westland produced 330 Sea Kings; outside of its British-based operators, various export customers were found for the Westland Sea King. including the Indian Naval Air Arm, the German Navy, the Royal Australian Navy, and the Royal Norwegian Air Force.[24]

While Sikorsky opted to terminate its own Sea King production line during the 1970s, the type has had a lengthy service life. In September 2009, it was reported that nearly 600 Sea Kings were believed to still be operational.[25]

Production

[edit]

The Sea King was produced in the USA, and under license in the U.K. by Westland, Italy by Augusta, Canada by United Aircraft of Canada, and in Japan by Mitsubishi.[26] Total production was about 1100 to 1300.[citation needed] The S-61 family includes the S-61L and S-61N, which are commercial models. The S-61R, which is the CH-3C/E Sea King, HH-3E Jolly Green Giant, and HH-3F Pelican. The S-61 license built by Westland had different engines and is usually called the Westland Sea King. Canadian Sea Kings were called CH-124 and license made by United Aircraft of Canada. They were made in Italy by Agusta and called AS-61 and ASH-3. In Japan, the Mitsubishi version was called the HSS-2.[26]

Design

[edit]

The Sikorsky SH-3 Sea King is a twin-engine medium-sized amphibious rotorcraft. Many of the features on board the Sea King represented a considerable advancement over preceding helicopters. In addition to being fully amphibious and capable of operating under all weather conditions, it is the first operational American helicopter to be able to simultaneously hunt and destroy submarines.[5] Its twin-turboshaft powerplant layout gave the SH-3 a higher payload and greater reliability than previous anti-submarine helicopters.[4] In the event of a single engine failing, the Sea King could continue flying on a single engine.[27] The powerplant used on the Sea King was the General Electric T58-GE-8B, which was initially capable of generating up to 1,250 shp (930 kW) each.[5]

SH-3H deploying a dipping sonar, 1989

In normal operations, the Sea King typically would have a four-man crew on board; these being a pilot and copilot in the cockpit, and two aircrew stationed within the main cabin area. When conducting anti-submarine missions, the rear aircrew operated the aircraft's sensors and interpreted the generated data.[28] For search-and-rescue missions, the Sea King's cabin could accommodate up to 22 survivors. In a medical layout, a maximum of nine stretchers plus two medical officers could be carried. In the troop transport role, up to 28 soldiers can be accommodated.[29]

The Sea King features many design elements to support naval-orientated operations. The main rotor blades and the tail section can be folded via fully automated systems for storage on board ships.[5] The adoption of an amphibious hull allowed a Sea King to conduct a water landing and, being completely watertight, would enable the rotorcraft to remaining floating for prolonged periods on the ocean's surface. Deployable airbags in the aircraft's sponsons added to the rotorcraft's stability and buoyancy, resisting pitching and rolling.[6] The hull design was compatible with landing on challenging terrain, including ice, snow, swamp land, and tundra.[5] Wheels are installed in the sponsons for land operations.[5]

The armament fitted upon a Sea King could vary considerably. For anti-submarine missions, the aircraft could carry 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.[30] The Sea King could also be fitted to deploy the B57 nuclear bomb.[31] ASW equipment used on Sea Kings has included the AQS-13A/B/E dipping sonar which included specialized computers for processing sonar and sonobuoy data, various models of sonobuoys, ARR-75 Sonobuoy Receivers, and the ASQ-81 magnetic anomaly detector. The commonly fitted AKT-22 data link enabled the rapid dissemination of sonar information to other friendly elements.[32] Some later Sea King models featured the TACNAV digital navigation system (first generation GPS) and overhauled cockpit instrumentation for night vision compatibility.[33]

Operational history

[edit]
Helicopter Anti-Submarine Squadron HS-12 "Wyverns" flying SH-3H Sea Kings in formation, 1985
Several UH-3H Sea Kings taking flight to fight the Cedar Fire in San Diego, California, in 2003

During June 1961, the Sea King became operational with the US Navy as the HSS-2; at the time, it was not only the largest amphibious helicopter in the world, but was also the first all-weather rotorcraft to reach production status for the US Navy.[5] When the unified aircraft designation system was introduced, the rotorcraft's designation was changed to SH-3A. It was used primarily for anti-submarine warfare: the largely involved the detection and tracking of Soviet submarines. In the event of open warfare breaking out between the two powers, Sea Kings would have been used to attack these submarines with the intent to sink them.[34]

The Sea King was able to operate from the flight decks of many of the US Navy's vessels as well as shore bases. It could also operate from offshore platforms to extend their surveillance and strike ranges. The type was capable of conducting nighttime ASW operations, albeit these usually posed considerable difficulty for the flight crew.[35][36]

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 near the carrier as a plane guard, ready to rescue air crew who crashed during takeoff or landing.[37] They were routinely used in a logistical capacity at sea, transferring personnel, mail, and other lighter cargoes between vessels.[35]

The Royal Canadian Navy (RCN) became a major operator of the Sikorsky CH-124 Sea King following its introduction to service in 1963. It remained Canada's dominant maritime helicopter for over 50 years, finally being withdrawn in 2018.[38] One notable innovation in Canadian operations, which was subsequently adopted by several other nations, was the use of a winch 'hauldown' landing and securing method, referred to as a 'Beartrap'. This device considerably increased the ability of Sea Kings to land in difficult conditions, such as on small flight decks or during poor weather conditions.[38][39]

The Sea King was exported in large numbers to various nations, such as Brazil, Italy, Japan and the United Kingdom.[40] Several operators have kept their Sea Kings in use for more than 50 years.[41][42]

During the Vietnam War, SH-3s rescued the crews of downed aircraft at sea and over land, typically being equipped with self-sealing fuel tanks, multiple machine guns and heavy armor when performing such missions.[43] Due to the type's greater range and the safety of having two engines, it was often used during rescue sorties into North Vietnam to retrieve downed aircrew.[7] The Sea King was also used for medical evacuations and disaster relief efforts.[35]

U.S. Marine Corps VH-3 Sea King, operating as Marine One, landing on the south lawn of the White House

The SH-3 was the primary helicopter for retrieving crewed space capsules starting with Mercury-Atlas 7 in May 1962.[44] Helicopter 66 was the primary recovery vehicle for Apollo missions 8 and 10 to 13.[45] In February 1971, an SH-3A, operating from the amphibious assault ship USS New Orleans, recovered Apollo 14.[46] A specialist search and rescue variant of the SH-3, the HH-3, also performed in this capacity.[6]

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 was pending under the VXX program.[47][48] In 1992, the US Justice Department sued Sikorsky over allegations of overcharged component pricing and deliberately misleading US Navy negotiators.[49] In 1997, the Justice Department issued further accusations against Sikorsky of willful overcharging on a contract to upgrade the Navy's Sea Kings.[50] In 2024, the VH-3D was replaced by the VH-92 Patriot as the Marine One helicopter.[51]

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.[52] 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).[53] They have been replaced by increasingly advanced variants of the SH-60 Sea Hawk.[35] In the early 21st century, following their drawdown in US service, there have been a number of initiatives to refurbish ex-military Sea Kings for continued operations; in addition to civil operators, nations such as Egypt and India acquired refurbished former US Sea Kings to supplement their own aging fleets.[54][55][56]

Variants

[edit]
A SH-3G Sea King helps recover Apollo 17. Ticonderoga is in the background
HH-3A on Bon Homme Richard
Army One, a VH-3A "Sea King" that served in the Presidential fleet from 1961 to 1976, on permanent display at the Nixon Library
SH-3G in 1981

US military

[edit]
XHSS-2
The only prototype of the H-3 Sea King.[19]
YHSS-2
Pre-production S-61 aircraft, seven built for the U.S. Navy,[57] re-designated YSH-3A in 1962.[19]
HSS-2
Original designation of the Sea King. Changed to SH-3A by the 1962 United States Tri-Service aircraft designation system
SH-3A
Anti-submarine warfare helicopter for the U.S. Navy; 245 built. Originally designated HSS-2.[4]
HH-3A
Combat search and rescue helicopter for the U.S. Navy. 12 converted from SH-3A.[4]
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.[58]
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.[citation needed] 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.[18]
RH-3A
Minesweeper helicopter for the U.S. Navy. Nine converted from SH-3A aircraft.[19]
VH-3A
VIP transport (Better known as Marine One or Army One 1957–76) helicopter for the U.S. Army and Marine Corps; originally designated HSS-2Z. Eight built, plus two SH-3A conversions rebuilt from damaged helicopters (one YHSS-2 and one SH-3A).[citation needed] The rest were returned to the U.S. Navy in 1975–76 and replaced by the VH-3D.
CH-3B
Military transport helicopter for the U.S. Air Force.[57]
SH-3D
Anti-submarine warfare helicopter for the U.S. Navy. 73 built and two conversions from SH-3As.[4]
VH-3D
VIP Presidential transport helicopter (better known as Marine One) for the U.S. Marine Corps, 11 built. It entered service in 1976.[59]
SH-3G
Cargo, utility transport helicopter for the U.S. Navy. 105 conversions from SH-3A and SH-3D.[4]
SH-3H
Upgrade of the SH-3G as an anti-submarine warfare (ASW) helicopter for the U.S. Navy.[4] It included SH-3G features with improvements for ASW, anti-ship missile detection and other airframe improvements. 163 SH-3A/D/Gs were upgraded to SH-3H configuration.[59]
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.[59]

Sikorsky designations

[edit]
S-61
Company designation for the Sea King.[4]
S-61A
Export version for the Royal Danish Air Force. Wider pontoons without flotation bags, a 530-liter center tank instead of a dipping sonar and no automatic powered folding system.[60]
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.[57]
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
Main article: Sikorsky S-61
Civil versions of the Sea King.
S-61R
Main article: Sikorsky 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").[61]

United Aircraft of Canada

[edit]
Main article: CH-124 Sea King
Canadian Sikorsky CH-124A Sea King
CH-124
Anti-submarine warfare helicopter for the Royal Canadian Navy (41 assembled by United Aircraft of Canada).[62]
CH-124A
The Sea King Improvement Program (SKIP) added modernized avionics as well as improved safety features.[62]
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.[62]
CH-124B2
Six CH-124Bs were upgraded to the CH-124B2 standard in 1991–1992. The revised CH-124B2 retained the sonobuoy processing gear to passively detect submarines but was 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.[62]
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.[62]
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.[62]

Westland

[edit]
Main article: Westland Sea King
Westland Sea King AEW.2A of the Royal Navy in 1998
German Navy Sea King in 1980, made by 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 was until 2017 also used by the Royal Air Force in a search and rescue capacity, and has been sold to many countries around the world.

Agusta

[edit]
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.[63]
AS-61N-1 Silver
License built model of the S-61N, with a shortened cabin.
AS-61R
version basing upon Sikorsky S-61R
AS-61VIP
VIP transport helicopter.[63]
ASH-3A (SH-3G)
Utility transport helicopter
ASH-3D
Anti-submarine warfare helicopter. Flown by the Italian, Brazilian, Iranian, Peruvian and Argentinian navies.[63]
ASH-3TS
VIP, executive transport mission helicopter. Also known as the ASH-3D/TS, the Italian Air Force operated 2 from 1975 until 2012.[63][64]
ASH-3H
Anti-submarine warfare helicopter.[63]

Mitsubishi

[edit]
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

[edit]
Map with current operators of the SH-3 in blue and former operators in red. This does not include S-61R or Westland users

Current

[edit]
A Brazilian Sea King
 Argentina
 Indonesia
An Iranian Navy Sea King in 2012
 Iran
 Peru
 Ukraine
 United States
A Sikorsky S-61 of the Japan Maritime Self Defense Force
 Venezuela

Former

[edit]
 Brazil
 Canada
 Denmark
 India
 Iraq
LASD's Rescue 5, flies offshore near Rancho Palos Verdes.
 Italy
 Japan
 Malaysia
 Saudi Arabia
 Spain
 United States

Aircraft on display

[edit]

Argentina

  • 0675 – S-61D-4 on static display at the Argentine Naval Aviation Museum in Bahia Blanca, Buenos Aires.[89][90]

Denmark

India

United States

An SH-3 Sea King on display at the Patuxent River Naval Air Museum.
Sikorsky SH-3H Sea King at the Hornet Carrier museum in California.

Accidents and incidents

[edit]
  • Malaysia (Royal Malaysia Airforce)
Further information: Category:Accidents and incidents involving the Sikorsky S-61

Specifications (SH-3D)

[edit]
Orthographically projected diagram of the SH-3 Sea King
Orthographically projected diagram of the SH-3 Sea King
External videos
video icon SH-3 at NAS Oceana Airshow, 2004
video icon External and cockpit footage of Sea King start up and take off

Data from Jane's All the World's Aircraft 1979-80[109]

General characteristics

  • Crew: 2 flight crew + 2 sonar operators
  • Capacity: (S-61A transport) 26 troops, or 15 stretchers, or 12 VIP passengers
  • Length: 54 ft 9 in (16.69 m)
  • Width: 16 ft 4 in (4.98 m) (rotors folded)
  • Height: 16 ft 10 in (5.13 m)
  • Empty weight: 11,865 lb (5,382 kg)
  • Gross weight: 18,626 lb (8,449 kg) (ASW mission)
  • Max takeoff weight: 21,500 lb (9,752 kg)
  • Powerplant: 2 × General Electric T58-GE-10 turboshaft engines, 1,400 shp (1,044 kW) each (total power limited to 2,500 hp (1,864 kW) by main gearbox)[110]
  • Main rotor diameter: 62 ft 0 in (18.90 m)
  • Main rotor area: 3,019 sq ft (280.5 m2)
  • Blade section: NACA 0012[111]

Performance

  • Maximum speed: 144 kn (166 mph, 267 km/h)
  • Cruise speed: 118 kn (136 mph, 219 km/h) for max range
  • Range: 542 nmi (625 mi, 1,005 km) with max fuel, 10% reserves
  • Service ceiling: 14,700 ft (4,480 m)
  • Rate of climb: 2,200 ft/min (11.2 m/s) at sea level
  • (All performance figures at weight of 20,500 lb (9,300 kg))

Armament

  • Up to 840 lb (380 kg) of weapons total
  • 2× Mk 46/44 anti-submarine torpedoes (SH-3H)
  • Various sonobuoys and pyrotechnic devices
  • B57 nuclear depth charge

See also

[edit]

Related development

Aircraft of comparable role, configuration, and era

Related lists

References

[edit]

Further reading

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Sikorsky SH-3 Sea King

View on Grokipedia
from Grokipedia
The Sikorsky SH-3 Sea King (company designation S-61) is an American twin-engine (ASW) helicopter designed and built by , featuring an all-metal, amphibious fuselage with retractable landing gear and a fully articulated five-blade main rotor system powered by two engines. First flown on March 11, 1959, as the HSS-2 prototype, it entered U.S. Navy service in September 1961 as the world's first amphibious ASW helicopter capable of deploying dipping sonar and torpedoes from a single platform, replacing earlier hunter-killer teams. Developed in response to Cold War-era threats from Soviet submarines, the Sea King incorporated advanced features like automatic stabilization equipment, Doppler navigation, and all-weather hovering capabilities, enabling operations from aircraft carriers and over-water environments. Its design marked a significant advancement as the first production helicopter to use turboshaft engines, providing greater power (up to 1,400 shp per engine in later variants) and reliability compared to piston-powered predecessors like the Sikorsky HSS-1. The helicopter achieved notable milestones early in its career, including becoming the first to exceed 200 mph in level flight during an official trial in February 1962 and completing a non-stop transcontinental flight across the in March 1965. Over its production run from 1959 to 1981, Sikorsky manufactured 794 units, with an additional 679 built under license by companies in the United Kingdom (Westland), Italy (Agusta), and Japan (Mitsubishi), for a total exceeding 1,400 aircraft worldwide. The SH-3 family served in diverse roles beyond ASW, including search and rescue (as the HH-3 Jolly Green Giant), VIP transport for the U.S. President (VH-3D "Marine One"), mine countermeasures (RH-3), vertical replenishment, and even airborne early warning in conflicts like the Falklands War. In U.S. service, it played critical parts in the Vietnam War—rescuing downed pilots and conducting combat search and rescue—and in NASA's Gemini and Apollo programs for astronaut recovery from ocean splashdowns. The U.S. Navy phased out most SH-3 variants by 2006, though the VH-3D was used by the Marine Corps until the mid-2020s, being replaced by the VH-92A Patriot, while international operators continue flying upgraded models into the 21st century, amassing over 24 million flight hours collectively. Key specifications for the baseline SH-3A include a of 22,050 lb (10,000 kg), a range of 621 mi (1,000 km), a service ceiling of 14,700 ft (4,481 m), and armament provisions for two Mk 44 or Mk 46 torpedoes, sonobuoys, and depth charges. Its dimensions—72 ft 7 in (22.1 m) overall length, 62 ft (18.9 m) rotor diameter, and 16 ft 10 in (5.1 m) height—allowed carrier operations, while the watertight hull supported water landings for rescue missions.

Development

Origins

In the mid-1950s, amid escalating tensions and the proliferation of Soviet submarines, the U.S. sought to modernize its (ASW) fleet by developing a more capable platform. In 1957, the issued a formal requirement for a twin-engine ASW to replace the Sikorsky HSS-1 Seabat, prioritizing all-weather operational capability, amphibious design for seamless shipboard and water-based deployments, integration, and the ability to carry approximately 381 kg of ordnance. This requirement aimed to consolidate functions into a single versatile airframe, enhancing efficiency for carrier-based operations. Sikorsky Aircraft responded in 1958 with a proposal for what would become the company's S-61 project, led by founder , who drew foundational influences from the earlier S-56 (military H-34) design while scaling up for greater endurance and payload. The proposed helicopter featured a larger to house ASW equipment, a of four, and sufficient fuel for up to four hours of operation, alongside an automatic flight control system (AFCS) for improved stability and an automatic hovering coupler to facilitate deployment in rough seas. Retractable was incorporated to minimize aerodynamic drag during flight and enable smooth transitions between wheeled and water landings. Central to the S-61's were decisions tailored to naval demands, including a boat-hull with a 12-degree deadrise angle and stabilizing sponsons for effective amphibious performance on water surfaces. The configuration adopted a five-bladed main rotor for enhanced lift and reduced noise, complemented by a four-bladed for precise control, with provisions for automatic blade folding to fit carrier storage constraints. Sikorsky's S-61 proposal competed against designs from Kaman Aircraft and Vertol, but the selected Sikorsky for the development contract in 1959, paving the way for prototype construction and evaluation.

First flight and testing

The prototype Sikorsky XHSS-2 Sea King (BuNo 147137) was constructed at the company's facility in , and completed in early 1959. The aircraft's occurred on March 11, 1959, piloted by Sikorsky's assistant chief Robert Stewart Decker, during which it demonstrated excellent stability, hovering performance, and amphibious landing capability on water. These initial tests validated the design's twin-engine layout and all-weather potential, paving the way for further evaluations. U.S. Navy evaluation trials spanned from 1959 to 1962, encompassing (ASW) simulations with the integration of the AN/AQS-13 dipping sonar, carrier compatibility assessments aboard USS Lake Champlain (CVS-39) in mid-1961, and amphibious operations including ditching tests to confirm the watertight hull's effectiveness. Refinements to the automatic flight control system (AFCS) were also addressed during this period to enhance stability in adverse conditions, enabling reliable operations in rough seas and low visibility. In February 1962, the prototype set international speed records for helicopters over distances of 3 km, 100 km, 500 km, and 1,000 km, averaging over 200 mph, underscoring its performance envelope. Certification milestones followed swiftly: the issued a for the civil S-61L variant on November 24, 1961. The U.S. declared initial operational capability (IOC) for the SH-3A in September 1961, with the first production deliveries equipping antisubmarine squadrons HS-3 and HS-10. These achievements marked the transition from prototype testing to fleet integration, confirming the Sea King's role as a pioneering amphibious ASW platform.

Production

The U.S. awarded Sikorsky an initial production for 72 SH-3A helicopters in 1960, leading to manufacturing at the company's facility beginning in 1961, with the first delivery to the fleet occurring in September 1961. Sikorsky ultimately produced approximately 543 SH-3 variants for the U.S. military through the 1970s, encompassing the original SH-3A model as well as subsequent models like the SH-3D, which incorporated upgraded T58-GE-10 engines for enhanced performance. Production rates peaked at 10-12 units per month during the mid-1960s to meet growing demand, with each SH-3A costing around $1.2 million in 1961 dollars. Licensed manufacturing expanded the Sea King's global footprint, with in the assembling approximately 330 units starting in 1966, including for service and exports. In Italy, began production in 1968, delivering more than 130 Sea Kings, primarily for the Italian Navy's anti-submarine and utility roles. Mitsubishi Heavy Industries in assembled 185 helicopters from 1965 onward under license, equipping the with locally produced HSS-2 variants. U.S. production wound down in the as focus shifted to upgrades and exports, with the final assemblies supporting international orders; overall global output for the family exceeded 1,200 units when including all licensed builds.

Upgrades and

The upgrade from the SH-3A to the SH-3D variant in the late involved retrofitting over 100 existing SH-3A airframes with the AN/AQS-13 dipping sonar, which featured a longer deployment line for deeper operational depths, along with an improved AN/APS-44 for enhanced search capabilities. This program addressed limitations in the SH-3A's original AN/AQS-10 sonar and systems, significantly boosting (ASW) effectiveness without requiring full new production. In 1962, the VH-3A executive transport variant was developed specifically for presidential and VIP duties, with eight new-build airframes and one conversion from an SH-3A, incorporating luxurious interior modifications such as reinforced flooring, specialized seating, and secure communications equipment. To achieve extended range for over-water operations, the VH-3A included 92-inch rotor blade extensions for improved stability and a 180-gallon , enabling up to 540 miles of flight distance. During the 1970s, the SH-3H variant emerged as a key upgrade, with 163 SH-3A/D/G airframes modified to include advanced acoustic processing systems for data analysis and the AN/AQS-13B dipping for refined ASW detection. In the 1980s, further enhancements integrated (FLIR) sensors under the nose for night and low-visibility targeting, alongside compatibility for anti-ship missiles such as the AGM-119 Penguin, expanding the platform's roles to include surface strike missions beyond traditional ASW. Internationally, the Westland variant, produced under license for the Royal Navy and exported operators, incorporated country-specific enhancements like electronic countermeasures (ECM) suites for improved survivability in contested environments, alongside troop transport configurations. Similarly, the Agusta-built ASH-3D for the featured tailored ECM systems and upgraded for Mediterranean ASW operations, with 12 airframes later evolved into ASH-3H standards for extended acoustic and sensor integration. Amid delays in the MH-60R Seahawk replacement program during the and early , mid-life upgrades under the Service Life Extension Program (SLEP) were applied to SH-3D and SH-3H airframes, replacing dynamic components and extending airframe life from 4,000 to 10,000 flight hours to maintain fleet readiness until full retirement in the mid-.

Design

Airframe and configuration

The Sikorsky SH-3 Sea King features a twin-engine, all-weather configuration optimized for and maritime operations, incorporating an amphibious boat-hull that enables water landings and enhances buoyancy during over-water missions. The has a length of 54 feet 9 inches and an overall height of 16 feet 10 inches, providing a robust structure for shipboard storage with foldable rotors and tail section. The system consists of a five-blade main with a of 62 feet, constructed from all-metal blades for durability and equipped with hydraulic controls in a fully articulated hub to manage lift and maneuverability in adverse conditions. Complementing this is a four-blade anti-torque , which provides and yaw control during flight. For ground and deck handling, the SH-3 employs retractable tricycle landing gear paired with stabilizing floats that deploy to prevent tipping on carrier decks or rough surfaces. The utilizes corrosion-resistant materials, including specialized alloys and coatings, to mitigate the effects of saltwater exposure and ensure longevity in environments. Crew accommodations include a raised with side-by-side seating for two pilots, offering improved communication and visibility, while the main cabin provides space for two (ASW) operators at console stations and integrates a rescue hoist capable of 600-pound lifts for search-and-rescue tasks. The has an empty weight of 11,865 pounds (5,382 kg) and a of 22,050 pounds (10,000 kg), balancing capacity with operational range. Internal fuel is housed in bladder tanks with a capacity of 658 gallons (2,490 liters), supporting extended missions without frequent refueling.

Propulsion and powerplant

The Sikorsky SH-3 Sea King is powered by two engines mounted side-by-side above the cabin roof for optimal weight distribution and protection. Early production models, such as the SH-3A, utilized T58-GE-6 or T58-GE-8 variants rated at approximately 1,050 horsepower (military power) or 1,250 shaft horsepower (shp) maximum each. Later variants, including the SH-3D, incorporated upgraded T58-GE-10 engines delivering 1,400 shp each, enhancing performance in and utility roles. Some executive transport models, like the VH-3D, employed T58-GE-400B engines with similar 1,400 shp output for reliable operation in presidential missions. The power from these engines is transmitted through a main gearbox located directly aft of the engine compartment, designed with a reduction ratio of nearly 100:1 to convert the high engine RPM (up to 20,000) into suitable rotor speeds. The initial gearbox was rated for 2,300 shp total, while upgraded systems in later models handled up to 2,500 shp, incorporating freewheeling clutches to allow in case of engine failure and a to the gearbox. This transmission setup, connected to intermediate and tail gearboxes, ensures efficient power delivery to the five-bladed main rotor and four-bladed . The system features bladder-type tanks integrated into the forward and hull structure for balance and amphibious compatibility, with a standard capacity of 658 gallons (2,490 liters) across primary cells. Self-sealing tanks were incorporated in combat-configured variants to enhance survivability against battle damage, complemented by crash-resistant designs that minimize rupture risks during impacts. For extended missions, auxiliary tanks adding up to 244 gallons (924 liters) could be fitted, extending operational range to approximately 500 nautical miles depending on load and conditions. consumption averages about 1,200 pounds per hour across flight regimes, supporting the helicopter's versatile maritime operations. Maintenance of the propulsion system emphasizes accessibility, with modules designed for straightforward removal and installation via the upper cowlings. Routine inspections, including hot-section checks on the components, follow manufacturer intervals to ensure reliability in harsh naval environments, often supported by specialized contractors for prevention in saltwater operations.

Avionics, sensors, and armament

The Sikorsky SH-3 Sea King featured core avionics systems designed to support all-weather (ASW) operations, including the autostabilization system for precise vertical station-keeping and hover control, Doppler navigation radar such as the AN/APN-130 for velocity measurement over water, and tactical air navigation (TACAN) for accurate positioning relative to carrier-based forces. These elements enabled stable flight in adverse conditions, with the Doppler system providing ground-speed data essential for deployment and tactical maneuvering. ASW sensors formed the backbone of the SH-3's detection capabilities, centered on the AN/AQS-13 dipping sonar, which could be lowered on a 500-foot cable to depths of approximately 150 to 500 feet for active and passive acoustic interrogation of submerged targets. Complementing this was the AN/ASQ-81 (MAD), towed as a "" to sense distortions in the caused by , often deployed at low altitudes for maximum sensitivity. The helicopter could also deploy up to 20 sonobuoys for broader acoustic surveillance, processing their data through onboard computers to localize threats. For surface and environmental search, early variants incorporated the AN/APS-44 radar, while later upgrades in some models added infrared detection capabilities akin to the AN/AAS-44 system for night operations. Armament provisions emphasized ASW lethality, with internal bays accommodating two Mk 44 or Mk 46 homing torpedoes for engaging detected submarines, though early SH-3A models could carry up to four. Alternative loads included conventional s or, in specialized configurations, the B57 nuclear for strategic deterrence. Upgraded variants like the SH-3H integrated external hardpoints for anti-ship missiles, expanding beyond pure ASW to surface strike roles. For self-defense, door-mounted 7.62 mm machine guns provided limited protection against small surface threats. Communication systems ensured seamless integration with carrier strike groups, featuring UHF and VHF radios for voice coordination, alongside HF for extended range, and secure data links for real-time tactical updates. These were augmented by IFF (Identification Friend or Foe) transponders and encrypted channels to maintain operational security during ASW missions.

Operational history

United States service

The Sikorsky SH-3 Sea King entered service in September 1961, with Helicopter Antisubmarine Squadron 3 (HS-3) becoming one of the first operational units equipped with the type for (ASW) duties aboard antisubmarine carriers. HS-3's HSS-2 (later redesignated SH-3) helicopters, deployed on (CVS-18), played a key role in ASW patrols during the Cuban Missile Crisis in October 1962, supporting the naval quarantine of by conducting surveillance and escort missions near the island. During the Vietnam War, SH-3s conducted extensive carrier-based ASW patrols in the Gulf of Tonkin to counter potential Soviet submarine threats, while also performing search and rescue (SAR) missions for downed aircrews over water; squadrons such as Helicopter Combat Support Squadron 1 (HC-1) accumulated significant flight hours in these roles, with HC-1 alone rescuing 36 personnel, including 15 pilots, during operations in 1972. The helicopter's amphibious capabilities and speed enabled rapid response in hostile environments, contributing to the Navy's overall SAR efforts that saved thousands of lives throughout the conflict. SH-3 Sea Kings from Helicopter Combat Support Squadron 1 (HC-1) also supported NASA's Gemini and Apollo programs by recovering astronauts from ocean splashdowns, including the Apollo 17 mission in December 1972. In utility roles, the U.S. Air Force adapted the H-3 airframe as the HH-3E Jolly Green Giant for (CSAR) missions in from 1965 to 1975, featuring added armor plating to protect against ground fire, in-flight refueling probes for extended range, and defensive armament including miniguns. These modifications allowed HH-3Es to penetrate deep into enemy territory, often under heavy fire, to extract pilots and conduct medical evacuations. The SH-3 also served in presidential transport as the VH-3D variant, operated by for duties since 1976, equipped with secure communications systems for classified operations and anti-missile countermeasures such as infrared flares and radar chaff dispensers. The VH-3D's spacious cabin and reliability made it ideal for executive transport, with ongoing upgrades maintaining its role into the . The SH-3 was progressively phased out by the MH-60R Seahawk starting in the early 2000s for ASW missions, with the last operational Navy unit, Helicopter Combat Support Squadron 2 (HC-2), decommissioning its UH-3H variants in 2006 after over four decades of service.

International military operations

The Royal Canadian Navy acquired the CH-124 Sea King in the early 1960s primarily for (ASW) roles during the , deploying them aboard destroyers and frigates to patrol Atlantic and Pacific sea lanes against Soviet submarine threats. These s conducted routine ASW exercises and surveillance missions, contributing to operations in the North Atlantic. In 1991, during as part of the coalition, CH-124s supported maritime interdiction and logistics from Canadian replenishment ships, performing alongside ASW patrols in the . The fleet underwent multiple upgrades for extended service, but aging airframes led to its retirement on December 31, 2018, after over 55 years of operation, replaced by the CH-148 Cyclone. The Royal Navy's , a licensed British variant of the SH-3, entered service in 1969 and saw extensive use in ASW and utility roles. During the 1982 , Sea Kings from and other carriers provided critical ASW protection against Argentine submarines, while HC.4 troop transport variants ferried and supplies to contested islands, logging over 4,600 flight hours in harsh South Atlantic conditions. Later adaptations included (SAR) configurations, with HAS.5 models converted for utility and commando support. The Royal Navy continued employing Sea Kings for SAR missions until their final retirement on September 26, 2018, marking the end of nearly 50 years of service. The Italian Navy's Agusta-built ASH-3D Sea King, introduced in the 1970s, focused on ASW but evolved to include capabilities through integration of the , enabling strikes against surface vessels from 20-30 km range. In 1991, during the , Italian ASH-3Ds operated from the as part of the coalition, conducting ASW patrols and reconnaissance in the to secure maritime routes. The helicopters played a similar role in 2011 during NATO's over , providing ASW cover for Italian task groups enforcing the and arms embargo in the Mediterranean. Japan's Maritime Self-Defense Force (JMSDF) operates the Mitsubishi-built S-61 (HSS-2/SSH-1) variants since 1960, primarily for ASW patrols in the to counter regional threats. These helicopters, equipped with dipping and torpedoes, routinely deploy from destroyers like the Hatakaze-class for amid ongoing territorial disputes, contributing to JMSDF's operations. Similarly, the Brazilian Navy's SH-3 s, acquired in the , support utility and patrol missions, including riverine operations in the for and anti-smuggling efforts aboard multipurpose ships. During the Iran-Iraq War (1980-1988), Iran's Imperial Iranian Navy-operated SH-3 Sea Kings, acquired pre-revolution, conducted ASW and transport missions in the , protecting oil tankers amid the Tanker War phase where Iraqi forces targeted shipping. These helicopters, despite maintenance challenges from sanctions, provided reconnaissance and utility support from bases like .

Civilian and utility roles

The civilian variants of the , derived from the SH-3 Sea King, were certified by the for commercial operations in 1961, with the S-61L marking the first multi-engine turbine helicopter approved for scheduled airline passenger service. Airways introduced the S-61L into revenue service on , 1962, operating it as a 28-passenger transport on routes between and , among other short-haul flights. The S-61N variant, certified in 1962 with amphibious floats retained from the military design, followed suit for overwater passenger and utility missions, including shuttles to offshore oil platforms. From the 1970s onward, S-61N helicopters became integral to offshore support operations, transporting personnel and equipment to rigs in the and . deployed S-61Ns in the starting in 1972 under contract with Shell, leveraging the aircraft's range and stability for harsh marine environments. In the , operators like Offshore Logistics utilized similar S-61Ns for routine rig shuttles, benefiting from the helicopters' ability to interface with dynamically positioned platforms via advanced navigation aids. Search-and-rescue (SAR) adaptations of the S-61 extended its utility into humanitarian roles, particularly through the HH-3F Pelican variant operated by the U.S. from 1969 until its on May 6, 1994. The HH-3F, equipped with amphibious and kits, conducted over 23,000 missions and rescued more than 23,000 lives during its service. Internationally, Norway's Mk 43B, a licensed S-61 derivative, performed SAR operations until its in late 2023, with full replacement by the AW101 completed that year. Firefighting conversions further diversified the S-61's civilian applications, with operators like Carson Helicopters modifying S-61Ns into "Fire King" configurations starting in the 1980s for U.S. Forest Service contracts. These aircraft, fitted with 1,000-gallon water buckets or tanks, were deployed against wildfires through the 2000s, including notable incidents like the 2008 Weaverville crash during a Forest Service operation. Additional utility setups included interiors for remote area response, enhancing the platform's role in disaster relief. As of 2025, civilian S-61 operations are limited to a small number of private heavy-lift contractors, focusing on utility tasks in remote regions such as Alaska's and construction sectors. Operators like CHI Aviation maintain S-61Ns for external load missions up to 10,000 pounds, supporting infrastructure projects where fixed-wing access is impractical.

Variants

U.S. military variants

The Sikorsky SH-3 Sea King entered U.S. primarily as an (ASW) for the , with subsequent variants adapted for utility, VIP transport, and roles across the , Marine Corps, , and . These variants were developed from the baseline S-61 design, incorporating enhancements in engines, sensors, and mission-specific equipment to meet evolving operational needs during the era. Production and conversions emphasized amphibious capabilities, all-weather performance, and integration with carrier-based operations. The SH-3A was the initial production ASW variant for the U.S. Navy, entering service in 1961 with 245 built. It featured twin T58-GE-8 engines providing 1,250 shaft horsepower each and was equipped with the AN/AQS-10 dipping sonar for submarine detection, along with provisions for Mk 44 or Mk 46 torpedoes. The SH-3A also supported secondary roles such as (SAR), mine countermeasures, and astronaut recovery missions, demonstrating its versatility early in its career. The SH-3D, introduced in 1966, represented an upgraded ASW model with 156 new-build aircraft for the , becoming the most numerous and widely used variant. It incorporated more powerful T58-GE-10 engines rated at 1,400 shaft horsepower each, improving range and payload capacity, and featured the advanced AN/AQS-13 dipping sonar for enhanced passive and active detection. Additional improvements included better in-flight refueling provisions and upgraded for sonobuoy processing, enabling more effective coordination with surface ships in anti-submarine screens. Over time, many SH-3Ds were repurposed for non-ASW duties before eventual retirement. In the 1970s, the Navy converted 87 surplus SH-3D airframes to the SH-3G utility and transport configuration to support logistics and cargo operations. These conversions removed ASW-specific equipment like the dipping sonar, added larger cargo doors on both sides of the fuselage, and included provisions for external fuel tanks to extend ferry range. The SH-3G retained the T58-GE-10 engines and amphibious hull, allowing it to carry up to 12 passengers or 4,000 pounds of cargo in ship-to-shore resupply missions, particularly aboard aircraft carriers. The SH-3H, developed in the mid-1970s, upgraded 163 SH-3A, SH-3D, and SH-3G aircraft to improve ASW and anti-ship capabilities amid advancing threats. First flight of a converted occurred in 1972, featuring the AN/AQS-13B sonar variant, AN/ASQ-81 , and advanced for data analysis. It also added radar warning receivers for detecting incoming anti-ship missiles, with structural reinforcements for extended . The SH-3H served as a bridge to more modern platforms like the SH-60 Seahawk, remaining operational into the 2000s. The VH-3A and VH-3D variants were specialized executive transport models for the U.S. Marine Corps' squadron, serving as "" for presidential transport starting in 1962. Eight VH-3A were built with luxurious interiors, soundproofing, and secure communications, powered by the standard T58-GE-8 engines but without ASW gear. In the 1970s, eight additional VH-3D airframes were produced with T58-GE-402 engines for greater power, along with updated and systems; these continue limited service today for VIP missions. The HH-3F Pelican, a variant based on the Air Force's HH-3E Jolly Green Giant, was adapted for long-range SAR with 40 entering service in the late 1960s. Derived from S-61R airframes, it included in-flight refueling probes, a nose-mounted AN/APS-94 radar for over-water searches, and auxiliary fuel tanks for extended loiter times, enabling operations far offshore. Unlike the Navy's SH-3 series, the HH-3F emphasized rescue hoists and , crediting it with thousands of lives saved during its four-decade career.

Licensed production variants

The Sikorsky SH-3 Sea King was produced under by several international manufacturers, adapting the design for local military requirements in (ASW), (SAR), and transport roles. These variants incorporated indigenous engines, avionics, and weapons systems while retaining the core and twin-engine configuration of the original. totaled over 600 across four primary nations, enhancing and allied naval capabilities during the era. In the , manufactured the Sea King family starting in 1965 under a license agreement with Sikorsky. The initial HAS.1 variant served as an ASW helicopter for the Royal Navy, equipped with Rolls-Royce engines, MEL ARI 5995 I-band , and Plessey Type 195 ; 56 were built and entered service that year. The HC.4 followed as a troop transport and utility variant in 1979, featuring fixed undercarriage and uprated 1400-1 engines for improved payload; 42 were produced, some later adapted for SAR duties. Upgrades culminated in the HAS.6, which modernized earlier airframes with enhanced including Orange Reaper electronic support measures and deeper-dipping , while retaining I-band capabilities; at least 78 were upgraded between the 1980s and 1990s. Agusta in Italy began licensed production of the ASH-3D in 1968, focusing on ASW for the Marina Militare. This variant mirrored the SH-3D but integrated Italian avionics and engines; 25 were built (one by Sikorsky and 24 by ), armed with AS.12 anti-ship missiles and capable of deploying torpedoes or depth charges. The design emphasized amphibious operations from destroyers, with production continuing into the 1970s to support requirements. Mitsubishi Heavy Industries in Japan produced the HSS-2 starting in 1965 for the (JMSDF), incorporating indigenous , Japanese-manufactured engines, and systems tailored for Pacific ASW patrols. Approximately 77 were built through the 1980s, serving on helicopter destroyers and frigates until phased out by the SH-60J in the early . United Aircraft of Canada assembled the CH-124 from 1963 onward for the Royal Canadian Navy, with 37 of the total 41 aircraft built locally from kits under license. These ASW and SAR helicopters featured Canadian integrations and entered service for Atlantic and Pacific operations; later upgrades in the 1980s improved and navigation systems on select airframes.

Civilian and export variants

The Sikorsky S-61L was developed in 1961 as a commercial passenger transport variant, featuring a fuselage extended by 4 feet 3 inches compared to the military HSS-2 to accommodate greater payload capacity, and powered by two 1,350 shp CT58-140 engines. It first flew on November 2, 1961, and received FAA certification shortly thereafter, with 13 units produced for short-haul airline operations capable of carrying up to 28 passengers. Initial deliveries went to Airways, which operated the type on intra-California routes until the early 1970s. Closely related, the S-61N variant first flew on August 7, 1962, and was optimized for overwater missions with the retention of amphibious floats from the HSS-2 design, later updated to the Mk II standard with CT58-110 engines for improved performance in offshore environments. A total of 123 were built, with the last delivery in May 1980, and the type found widespread use in oil rig support and utility roles by operators including and the , where examples remained active into the 2010s. The S-61R emerged as a utility and heavy-lift derivative in the mid-1960s, with its first flight in 1963, incorporating a redesigned with a rear loading ramp, watertight hull, and retractable tricycle landing gear to facilitate cargo handling in and applications. Approximately 13 former military airframes were converted to civilian standards for non-military heavy-lift tasks, emphasizing external load capabilities for industries such as and development. Beyond dedicated civilian models, numerous SH-3 Sea Kings were exported for military and search-and-rescue roles outside standard U.S. or licensed production lines. Iran acquired over 20 SH-3D helicopters prior to 1979 for anti-submarine warfare and utility missions with the Imperial Iranian Navy, supplemented by additional units from international suppliers. Iraq received a limited number of SH-3 variants in the 1980s for naval operations during regional conflicts, though operational details remain sparse due to wartime losses. Saudi Arabia operated AS-61 Sea Kings in both anti-submarine and VIP transport configurations, including six Mark 47 ASW models delivered in the 1980s for Royal Saudi Navy service. In more recent decades, integrated SH-3H variants into its navy starting in the 1990s, with a significant acquisition of six ex-Spanish SH-3H helicopters in 2022 for a nominal , redesignated as SH-3G and entering service by mid-2024 to bolster and search-and-rescue capabilities. Malaysia's S-61A-4 , a derivative, served in utility and SAR roles until its retirement in 2020, marking the end of over 50 years of operation with the Royal Malaysian Air Force. The HH-3E "Jolly Green Giant" configuration, while primarily U.S. Air Force-operated for , influenced international adaptations, such as Egypt's use of SH-3 variants for similar overwater SAR missions since the 1970s. As of 2025, ongoing civilian conversions of S-61 airframes for persist, with operators like Coulson Aviation and Carson Helicopters equipping them with 1,000-gallon water tanks for , leveraging the type's robust heavy-lift heritage.

Operators

Current operators

The Sikorsky SH-3 Sea King and its derivatives remain in limited military and civilian service worldwide as of November 2025, primarily in anti-submarine warfare, search and rescue (SAR), utility transport, and heavy-lift roles. India
The Indian Navy operates the Sea King Mk42 and Mk47 variants, with a fleet of approximately 17 helicopters dedicated to anti-submarine warfare in the Indian Ocean and utility/SAR missions, bolstered by ongoing mid-life upgrades to enhance avionics and sensors. These aircraft continue to perform critical operations, including medical evacuations at sea, as demonstrated in late 2025 deployments from bases like INS Shikra. Peru
The Peruvian commands one of the largest remaining Sea King fleets in , utilizing SH-3D and recently acquired SH-3H variants for transport, SAR, surveillance, and support in the Amazon and Pacific regions. The fleet, numbering around a dozen aircraft, underwent modernization efforts in recent years, including the integration of six additional SH-3H units from in 2023 to sustain operational readiness. United States
The United States Marine Corps operates approximately eight VH-3D Sea King helicopters in a limited VIP transport role, including as "Marine One" for presidential duties, as of November 2025, while transitioning to the VH-92A Patriot. Pakistan
The Pakistan Navy continues to operate Sea King helicopters, including upgraded ex-UK variants inducted in recent years, for , SAR, and maritime support roles. The fleet remains active, participating in multinational exercises such as AMAN-25 in February 2025. Brazil
The Brazilian operates approximately nine SH-3A and SH-3H Sea King helicopters for , SAR, and missions as of 2025. Civilian operators
In the United States, private firms maintain significant S-61 fleets for commercial applications. Carson Helicopters operates around 12 S-61 variants equipped with composite rotor blades for enhanced performance in and heavy-lift tasks. Similarly, Croman Corporation employs 11 S-61 series helicopters, including S-61N, S-61A, and modified SH-3H models, for , logging, and operations across domestic and international contracts. These civilian adaptations emphasize the type's enduring reliability in demanding environments.

Former operators

The United States Navy retired its SH-3 Sea King fleet in 2006 after over 40 years of service, with the last operational H-3 helicopters decommissioned and replaced by the more advanced SH-60 Seahawk variants for and utility roles. The phased out its HH-3F Pelican variant in 1994, ending the amphibious era of its aviation assets and transitioning to non-amphibious helicopters like the HH-60 Jayhawk for missions. Similarly, the retired its HH-3E Jolly Green Giant by the end of 1995 following its use in combat rescue operations during the , succeeded by improved HH-60 Pave Hawk models. In the , the Royal Navy retired its variants in September 2018 after nearly 50 years of service, including and duties post-Falklands War and in , with over 100 helicopters operated in total and replaced by and helicopters. The Royal Air Force followed suit, retiring its Sea King HAR.3 search and rescue helicopters in 2016, marking the end of their utility in civilian-contracted SAR operations. Canada operated 41 CH-124 helicopters, which were retired on December 31, 2018, after more than 55 years and over 550,000 flight hours, primarily in anti-submarine and roles, and replaced by the CH-148 . Australia's retired its fleet of 18 Mk.50 helicopters in December 2011 after 36 years of service, accelerated following a fatal crash in 2005 that highlighted challenges, and transitioned to the MH-60R Seahawk for maritime operations. Among other nations, Belgium's Air Component retired its five Westland Sea King Mk.48 helicopters in March 2019 after 43 years, primarily used for , and replaced by the NH90 NFH. Denmark's retired its S-61 Sea Kings in 2011 following 45 years of service in , with the fleet sold off afterward. retired its Westland Sea King Mk.43B fleet in December 2023 after 50 years and over 200,000 flight hours in missions, succeeded by the AW101 SAR Queen. On the civilian side, major airlines and operators phased out S-61L/N variants by the 1980s due to high fuel consumption and the rise of more efficient twin-rotor designs like the S-92, though specialized and roles continued with converted ex-military airframes into the .

Preservation and incidents

Surviving aircraft and displays

Several notable examples of the Sikorsky SH-3 Sea King and its variants are preserved in the United States. The in , displays an SH-3D Sea King, highlighting its role as an early that entered service in the . A VH-3D presidential transport variant, which served during multiple administrations including that of , is exhibited at the Richard Nixon Presidential Library and Museum in . Additionally, the National Museum of the in , features an HH-3E Jolly Green Giant (serial number 67-14709), a that completed over 32 months of service in , rescuing 27 airmen during the . Internationally, preserved Sea Kings reflect the type's global adoption. In the , the at RNAS Yeovilton houses a Westland-built Sea King HAS.5 (XZ574), a veteran that underwent upgrades from HAS.2 to HAS.6 standards during its operational life. preserves a CH-124 Sea King at the National Air Force Museum of Canada in , commemorating its 55 years of service in maritime surveillance and anti-submarine roles for the Royal Canadian Air Force. In , an Agusta-built ASH-3D Sea King is on static display at the in Vigna di Valle, representing the variant's utility in transport and VIP missions. A number of Sea King airframes remain airworthy, primarily in civilian heavy-lift applications. In the United States and elsewhere, upgraded S-61 variants continue operations in , , and , with ongoing modernization programs extending their service life into 2025. As of 2025, dozens of SH-3 Sea King airframes and derivatives survive worldwide in museums, static displays, and limited operational roles, underscoring the helicopter's enduring legacy despite widespread retirements from frontline military service. In 2023, retired its Sea King Mk.43B fleet after 51 years, with one example preserved at the Norwegian Aviation Museum in .

Notable accidents and incidents

The Sikorsky SH-3 Sea King and its variants experienced numerous accidents and incidents throughout their operational history, reflecting the challenges of , combat operations, and aging airframes. The Network records 83 hull-loss accidents for the S-61 family, including military and civilian variants, with fatalities ranging from single-crew losses to multi-personnel tragedies. Common contributing factors included mechanical issues such as engine or rotor failures, during complex missions, and environmental hazards like or enemy action. During testing in the early , the SH-3A suffered a significant setback when aircraft BuNo. 149686 crashed into the approximately 6 miles west of , on 30 January 1964. The , conducting a high-altitude evaluation flight, experienced an in-flight breakup and plummeted from 1,500 feet, killing all three crew members on board. This incident highlighted early design and structural challenges in the Sea King's development. In the Vietnam War era, Sea Kings were frequently exposed to combat risks, leading to several losses. On 19 July 1967, SH-3A BuNo. 151538 from Helicopter Anti-Submarine Squadron 4 (HS-4) was shot down by North Vietnamese ground during a (CSAR) support mission near Phu Ly, . All four members—Lt. Dennis Peterson, Ens. Donald Frye, 2nd Class William Jackson, and 2nd Class Donald McGrane—were killed in the crash. The incident underscored the vulnerability of s in hostile environments, with HH-3E "Jolly Green Giant" variants suffering additional losses in CSAR roles, including a 15 April 1970 crash of HH-3E 66-13280 near Kontum that killed two of five amid . The on also damaged multiple aircraft, including SH-3s from HS-3 squadron, contributing to broader operational disruptions though specific helicopter losses were not total write-offs. The in 1982 saw licensed variants in high-risk operations, culminating in a tragic ditching on 19 May when RAF Sea King HC.4 ZA294, carrying SAS troops from , crashed into the South Atlantic due to a bird strike. Of the 31 on board, 22 were killed (including 2 crew), with 9 survivors rescued after enduring in freezing waters; this remains the worst single accident for British special forces. The sinking of HMS Coventry on 25 May by Argentine bombs prompted extensive Sea King rescue efforts, though no additional ditchings were reported in that specific operation. Peacetime incidents highlighted ongoing mechanical concerns. In , the Royal Australian Navy's Sea Kings faced scrutiny after a series of mishaps, including a 2 April 2005 crash of N16-100 during a humanitarian mission on Nias Island, , which killed nine personnel and led to fleet grounding and safety reviews; this accelerated the decision to retire the type in December 2011 after 37 years of service. Overall, these events prompted design modifications, such as improved rotor systems and crashworthy features, to mitigate risks in subsequent variants. Some wreckage from lost Sea Kings has been preserved for study or display, providing insights into failure modes.

Specifications

General characteristics (SH-3D)

The Sikorsky SH-3D Sea King featured a crew of four, comprising two pilots and two (ASW) operators responsible for and weapons systems operation. Its dimensions were optimized for shipboard operations, with an overall length of 72 ft 7 in (22.15 m), a main rotor diameter of 62 ft (18.90 m), and a height of 16 ft 10 in (5.13 m). The empty weight stood at 11,865 lb (5,382 kg), while the maximum takeoff weight reached 22,050 lb (10,000 kg), allowing for substantial payload capacity in ASW configurations. Power was supplied by two T58-GE-10 engines, each rated at 1,400 shp (1,044 kW), providing reliable performance for maritime environments. The SH-3D's armament consisted of two Mk 46 torpedoes for engaging , complemented by provisions for sonobuoys to detect underwater threats. The fuel capacity was 1,553 L (410 US gal) internal, supporting extended patrol durations.

Performance (SH-3D)

The SH-3D Sea King demonstrated a maximum speed of 166 mph (267 km/h, 144 kn) at sea level, enabling effective deployment in (ASW) operations over maritime environments. This top speed supported to search areas while maintaining stability for sensor deployment. In cruise configuration, the helicopter achieved 136 mph (219 km/h, 118 kn), balancing fuel efficiency with mission requirements during typical patrols. Operational range with standard internal fuel was 540 nmi (621 mi, 1,000 km), sufficient for carrier-based ASW missions without refueling, though extended ferry range reached approximately 540 nmi (621 mi, 1,000 km) using auxiliary tanks for relocation or prolonged transits. The service stood at 14,700 ft (4,480 m), allowing operations above most surface threats, complemented by a of 1,410 ft/min (7.2 m/s) for quick altitude gains during evasion or positioning. Hover performance included a of 10,500 ft (3,200 m) in ground effect (IGE), critical for dipping in littoral zones, with typical ASW mission endurance of 4 hours factoring in weapon loads and loiter time. Structural limits permitted g-loads of +3.5/-1.0, ensuring maneuverability within safe envelopes for evasive actions or recoveries without risking integrity. These parameters defined the SH-3D's , prioritizing endurance and low-speed handling over high-performance , as suited to its naval role.
Performance ParameterValue
Maximum speed (sea level)166 mph (267 km/h, 144 kn)
Cruise speed136 mph (219 km/h, 118 kn)
Range (standard fuel)540 nmi (621 mi, 1,000 km)
Ferry range (auxiliary fuel)540 nmi (621 mi, 1,000 km)
Service ceiling14,700 ft (4,480 m)
Rate of climb1,410 ft/min (7.2 m/s)
Hover ceiling (IGE)10,500 ft (3,200 m)
Endurance (typical ASW mission)4 hours
G-limits+3.5/-1.0

References

  1. https://sikorskyarchives.com/home/sikorsky-product-history/helicopter-innovation-era/sikorsky-s-61/
  2. https://www.history.navy.mil/content/history/museums/nnam/explore/collections/aircraft/s/sh-3a-sea-king.html
  3. https://www.usni.org/magazines/naval-history-magazine/2012/january/historic-aircraft-king-sea
  4. https://www.midway.org/visit/aircraft-gallery/sh-3-sea-king
  5. https://www.twz.com/air/vh-92-patriot-taking-over-marine-one-duties-full-has-slipped-till-end-of-decade
  6. http://www.aviastar.org/helicopters_eng/sik_s-61.php
  7. https://www.militaryfactory.com/aircraft/detail.php?aircraft_id=280
  8. https://www.thisdayinaviation.com/11-march-1959/
  9. https://www.navair.navy.mil/node/22401
  10. https://xplanereviews.com/forums/topic/121-aircraft-review-sikorsky-sh-3-sea-king-s-61-by-virtavia-and-dawson-design/
  11. https://apps.dtic.mil/sti/tr/pdf/ADA086529.pdf
  12. https://www.nytimes.com/1961/11/24/archives/helicopter-approved-twinturbine-sikorsky-s61l-is-certified-by-faa.html
  13. https://jproc.ca/rrp/rrp3/seaking.html
  14. https://www.airvectors.net/avs61_1.html
  15. https://www.airvectors.net/avs61_2.html
  16. https://www.seaforces.org/marint/Royal-Navy/AIRCRAFT/Sea-King-RN.htm
  17. https://www.helis.com/database/model/Mitsubishi-Sea-King/
  18. https://tailhooktopics.blogspot.com/2013/02/us-navy-asw-sh-3-sea-king-variations.html
  19. https://www.seaforces.org/marint/Italian-Navy/Aviation/ASH-3-Helicopter.htm
  20. https://www.navy.mil/Resources/Fact-Files/Display-FactFiles/Article/2166700/vh-3d-sea-king-helicopter/
  21. https://vertipedia.vtol.org/aircraft/getAircraft/aircraftID/181
  22. https://www.globalsecurity.org/military/systems/aircraft/sh-3.htm
  23. https://www.airfighters.com/aircraft-data/sikorsky-sh-3d-sea-king
  24. https://www.globalsecurity.org/military/systems/aircraft/uh-3.htm
  25. https://www.history.navy.mil/content/history/museums/nnam/explore/collections/aircraft/v/vh-3-marine-one.html
  26. https://jproc.ca/rrp/rrp3/seaking_equipment_details.html
  27. https://avgeekery.com/built-to-hunt-soviet-subs-the-sea-king-dominated-every-mission-it-tackled/2/
  28. https://www.history.navy.mil/content/dam/nhhc/research/publications/Publication-PDF/CordonOfSteel.pdf
  29. https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/196060/sikorsky-hh-3e-jolly-green-giant/
  30. https://thecanadianencyclopedia.ca/en/article/ch-124-sea-king
  31. https://airforcemuseum.ca/aircraft/ch-124-sea-king/
  32. https://www.canada.ca/en/department-national-defence/maple-leaf/rcaf/migration/2018/final-farewell-to-the-sea-king.html
  33. https://planehistoria.com/westland-sea-king/
  34. https://www.royalnavy.mod.uk/news/2018/september/26/180926-final-flight-sea-king
  35. https://www.milavia.net/specials/italian-navy-sea-king/
  36. https://www.usni.org/magazines/proceedings/1991/july/special-foreign-aircraft-carrier-redux
  37. https://www.seaforces.org/marint/Japan-Maritime-Self-Defense-Force/AIRCRAFT/Mitsubishi-HSS-2.htm
  38. https://russiancouncil.ru/en/analytics-and-comments/analytics/vmf-brazilii-na-zashchite-dikovinnykh-beregov/
  39. https://www.key.aero/article/running-empty-how-budget-cuts-have-damaged-iranian-naval-aviation
  40. https://www.thisdayinaviation.com/1-march-1962/
  41. https://www.globalair.com/aircraft-for-sale/specifications?specid=693
  42. https://the-norwegian.com/north-sea-helicopter-incidents-1964-1993/
  43. https://www.bristowgroup.com/news-media/articles/detail/7513/from-humble-beginnings-to-one-of-the-largest-civilian
  44. https://www.history.uscg.mil/browse-by-topic/aviation/significant-dates/
  45. https://verticalmag.com/news/norway-retires-sea-king-welcomes-new-leonardo-aw101-for-search-and-rescue/
  46. https://www.linkedin.com/pulse/carsons-fireking-challenges-performance-s-61-carson-helicopters-inc
  47. https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR1006.pdf
  48. https://www.fairlifts.com/helicopters/the-sikorsky-s-61-helicopter-a-heavy-lift-workhorse-in-the-sky/
  49. https://chiaviation.com/fleet/
  50. https://www.uswarplanes.net/seaking.pdf
  51. https://www.usni.org/magazines/naval-history-magazine/2024/february/presidential-helicopters
  52. https://www.history.navy.mil/content/history/museums/nnam/explore/collections/aircraft/h/hh-3f-pelican.html
  53. https://www.armedconflicts.com/Agusta-Sikorsky-ASH-3D-Sea-King-t212568
  54. https://www.helis.com/database/model/ASH-3D/
  55. https://www.helis.com/database/model/681/
  56. https://www.key.aero/article/peruvian-navy-presses-new-sea-kings-service
  57. https://www.flightglobal.com/helicopters/spain-agrees-sale-of-six-sea-kings-to-peru-for-symbolic-600-fee/150433.article
  58. https://www.shephardmedia.com/news/defence-helicopter/malaysia-decides-retire-nuri-helicopter-fleet/
  59. https://coulsonaviation.com/aerial-firefighting/
  60. https://wildfiretoday.com/information-about-the-carson-s-61-helicopters/
  61. https://www.scribd.com/document/887058128/Indian-Naval-Aviation-2025
  62. https://indiannavy.gov.in/content/seaking-42b
  63. https://www.riotimesonline.com/peruvian-navy-modernizes-amazon-fleet/
  64. https://seawaves.com/bap-pisco-travelling-to-rota-to-embark-six-sea-kings/
  65. https://theaviationist.com/2025/01/23/vh-3d-and-joint-base-andrews-once-again-play-key-roles-in-u-s-presidential-inauguration/
  66. https://khabarkada.com/aman-2025-concludes-with-major-display-of-pakistan-navys-capabilities/
  67. https://www.airhistory.net/photo/700286/N-3012
  68. https://www.carsonhelicopters.com/s-61-crmb
  69. https://croman.net/entire-fleet/
  70. https://www.patriotspoint.org/things-to-do/aircraft/sh-3g-sea-king
  71. https://cgaviationhistory.org/hangar-flying/pelican-tales-the-last-of-the-coast-guards-amphibious-aircraft/
  72. https://www.militaryfactory.com/aircraft/detail.php?aircraft_id=129
  73. https://www.airtattoo.com/riat-2022/aircraft/westland-sea-king-har3-civilian/
  74. https://verticalmag.com/press-releases/canadian-armed-forces-honor-the-long-serving-ch-124-sea-king-helicopter/
  75. https://downunderaviationnews.wordpress.com/ran-sea-king-retirement/
  76. https://www.naval-technology.com/news/newsran-decommissions-sea-king-helicopters/
  77. https://www.key.aero/article/last-belgian-sea-king-retires
  78. https://www.airforce-technology.com/news/news115711-html/
  79. https://www.aero-news.net/index.cfm?do=main.textpost&id=c1230439-c81a-4621-893d-633cc1bf0168
  80. https://abpic.co.uk/pictures/view/1260005
  81. https://www.jetphotos.com/photo/11258757
  82. https://www.key.aero/article/norway-bids-farewell-abdicating-sea-kings
  83. https://asn.flightsafety.org/asndb/type/S61
  84. https://asn.flightsafety.org/wikibase/275248
  85. https://asn.flightsafety.org/wikibase/155791
  86. https://aviation-safety.net/wikibase/71053
  87. https://www.usni.org/magazines/naval-history-magazine/2022/april/failure-falklands
  88. https://www.check-six.com/Helo66/h-seaking.htm
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