Sikorsky S-61

S-61L/S-61N
	HeliJet's S-61N at Vancouver International Airport
Role	Medium-lift transport/airliner helicopter
Manufacturer	Sikorsky Aircraft
First flight	March 11, 1959
Introduction	September 1961
Status	Active service
Primary users	VIH Aviation Group; CHC Helicopter Bristow Helicopters ; HeliJet
Number built	119
Developed from	SH-3 Sea King
Variants	Sikorsky S-61R

S-61N of Air Greenland for Passenger/Cargo operations at Narsarsuaq Airport, Greenland

An S-61 helitanker uses a snorkel to refill its internal water tanks

The Sikorsky S-61L and S-61N are civil variants of the successful SH-3 Sea King helicopter. They are two of the most widely used airliner and oil rig support helicopters built.^[1]

Design and development

In September 1957, Sikorsky won a United States Navy development contract for an amphibious anti-submarine warfare (ASW) helicopter capable of detecting and attacking submarines.^[1] The XHSS-2 Sea King prototype flew on 11 March 1959. Production deliveries of the HSS-2 (later designated SH-3A) began in September 1961, with the initial production aircraft being powered by two 930 kW (1250shp) General Electric T58-GE-8B turboshafts.

Sikorsky was quick to develop a commercial model of the Sea King.^[1] The S-61L first flew on 2 November 1961, and was 4 ft 3in (1.27m) longer than the HSS-2 in order to carry a substantial payload of freight or passengers. Initial production S-61Ls were powered by two 1350shp (1005 kW) GE CT58-140 turboshafts, the civil version of the T58. The S-61L features a modified landing gear without float stabilisers.

Los Angeles Airways was the first civil operator of the S-61^[2] introducing them on 11 March 1962, for a purchased price of $650,000 each.^[3]

On 7 August 1962, the S-61N made its first flight.^[1] Otherwise identical to the S-61L, this version is optimized for overwater operations, particularly oil rig support, by retaining the SH-3's floats. Both the S-61L and S-61N were subsequently updated to Mk II standard with improvements including more powerful CT58-110 engines giving better hot and high performance, vibration damping and other detail refinements.

The Payloader, a stripped down version optimised for aerial crane work, was the third civil model of the S-61.^[1] The Payloader features the fixed undercarriage of the S-61L, but with an empty weight almost 2000 lb (900 kg) less than the standard S-61N.

Carson Helicopters was the first company to shorten a commercial S61. The fuselage is shortened by 50in (1.6m) to increase single engine performance and external payload.^[4]

A unique version is the S-61 Shortsky conversion of S-61Ls and Ns by Helipro International.^[1] VIH Logging was the launch customer for the HeliPro Shortsky conversion which first flew in February 1996.

One modification for the S-61 is the Carson Composite Main Rotor blade. These blades replace the original Sikorsky metal blades which are prone to fatigue. The Carson Composite Main Rotor blades permit a modified aircraft to carry an additional 2,000 lb (907 kg) load, fly 15 kn (28 km/h) faster and increases range 61 nmi (113 km).^[4]

The latest version is the modernized S-61T helicopter. The US State Department has signed a purchase agreement for up to 110 modernized S-61T aircraft for passenger and cargo transport missions in support of its worldwide operations. The first two modernized S-61 aircraft will support missions for the U.S. Embassy in Afghanistan.^[5]

Variants

S-61L: Non-amphibious civil transport version. It can seat up to 30 passengers (13 Built).
S-61L Mk II: Improved version of the S-61L helicopter, equipped with cargo bins.
S-61N: Amphibious civil transport version.
S-61N Mk II: Improved version of the S-61N helicopter.
S-61 Payloader: Stripped down machine optimised for aerial crane work; features the fixed undercarriage of the S-61L, but with an empty weight almost 900 kg (2000 lb) less than the standard S-61N.
S-61 Shortsky: Shortened conversion of the S-61L and N, designed to increase single engine performance and external payload.
S-61T Triton: S-61 modernized upgrade by Sikorsky and Carson; initial models converted were S-61N^[6]

Operators

Former operators are marked by italics
Argentina

Argentine Air Force - One S-61N^[7]

Brunei

Brunei Shell Petroleum

Canada

Spain

Sociedad de Salvamento y Seguridad Marítima (Helicsa)

Greenland

Air Greenland

Ireland

Irish Coast Guard (CHC Helicopter)

Lebanon

3 Sikorsky S-61N operated by the Lebanese Air Force on behalf of the Ministry of Interior for firefighting purposes

Maldives

Hummingbird Helicopters

Netherlands

Norway

Helikopter Service

Pakistan

Pakistan International Airlines

United Kingdom

BEA Helicopters
Bristow Helicopters
British Airways Helicopters
British Caledonian Helicopters
British International Helicopters
Her Majesty's Coastguard - operating Sikorsky S-61N

United States

Carson Helicopters
Columbia Helicopters
Croman Corporation
Helicopter Transport Services
Los Angeles Airways
New York Airways
ERA Helicopters
U.S. State Department two units^[8] (108 units on order^[6])

Notable accidents

N300Y, the S-61L prototype, departing from Disneyland Heliport on a flight five years prior to its accident flight.

On 22 May 1968, Los Angeles Airways Flight 841 crashed near Paramount, California, resulting in the loss of 23 lives. The accident aircraft, N303Y, serial number 61060, was a Sikorsky 61L en route to Los Angeles International Airport from the Disneyland Heliport in Anaheim, California.

On 14 August 1968, Los Angeles Airways Flight 417 crashed in Compton, California, while en route to the Disneyland Heliport in Anaheim, California from Los Angeles International Airport, resulting in the loss of 21 lives. The accident aircraft, N300Y, serial number 61031, was the prototype of the Sikorsky S-61L.^[9]

On 25 October 1973, an Air Greenland S-61N, OY-HAI "Akigssek" ("Grouse") crashed about 40 km south of Nuuk, resulting in the loss of 15 lives. It was en route to Pamiut from Nuuk. The same aircraft had an emergency landing on the Kangerlussuaq fjord 2 years earlier, due to double flameout on both engines because of ice in the intake.^{[citation needed]}

On 16 May 1977, New York Airways' commercial S-61-L, N619PA, suffered a static rollover onto its starboard side at the heliport on top of the Pan Am Building while boarding passengers. The accident killed four boarding passengers and one woman on the street. 17 additional passengers and the three flight crew members were uninjured.^[10] The landing gear collapse was a result of metal fatigue in the helicopter's main landing gear shock-absorbing strut assembly, which caused the helicopter to tip over without warning. The accident resulted in the permanent closure of the Pan Am Building heliport.^[11]

On 16 July 1983, British Airways Helicopters' commercial S-61 G-BEON crashed in the southern Celtic Sea, in the Atlantic Ocean, while en route from Penzance to St Mary's, Isles of Scilly in thick fog. Only six of the 26 on board survived. It sparked a review of helicopter safety and was the worst civilian helicopter disaster in the UK until 1986.^{[citation needed]}

On March 20, 1985, an Okanagan Heliocpters S-61N (C-GOKZ) ditched in the Atlantic Ocean off of Owl's Head, Nova Scotia. The aircraft was enroute from the MODU Sedco 709 offshore Nova Scotia to the Halifax International Airport(YHZ)when it suffered total loss of transmission fluid from the Main Gear Box. There were 15 passengers and 2 crew on board. There were no injuries during the ditching, however several passengers suffered from varying degrees of hypothermia. As a result of this incident, there was a dramatic increase in thermal protection and other advancements in helicopter tranportation suits for offshore workers on the east coast of Canada.

12 July 1988 a British International Helicopters S-61N ditched into the North Sea, no injuries.

On 5 August 2008, two pilots and seven firefighters assigned to the Iron Complex fire in California's Shasta-Trinity National Forest, were killed when Carson Helicopters Sikorsky S-61N helicopter N612AZ crashed on take-off. Of the 13 people reported to be on-board, one other pilot and three firefighters survived the crash with serious or critical injuries. Both FAA and National Transportation Safety Board are investigating.^[12]^[13]

Specifications (S-61N Mk II)

Data from International Directiory of Civil Aircraft^[1]

General characteristics

Crew: 2 pilots
Capacity: up to 30 passengers

Performance

References

^ ^a ^b ^c ^d ^e ^f ^g ^h Frawley, Gerard: The International Directory of Civil Aircraft, 2003-2004, p. 194. Aerospace Publications Pty Ltd, 2003. ISBN 1-875671-58-7.
^ Apostolo, G. "Sikorsky S-61".The Illustrated Encyclopedia of Helicopters. Bonanza Books, 1984. ISBN 0-517-439352.
^ "The Self-Supporting Helicopter" Time Magazine December 26, 1960
^ ^a ^b Carson Helicopters (2009). "About Carson Helicopters". Retrieved 2009-01-12.
^ Press Releases: U.S. State Department Accepts Modernized S-61TM Helicopters for Use in Afghanistan
^ ^a ^b Sikorsky S-61T gains new life in State Department program
^ S-61 in FAA
^ Press Releases - U.S. State Department Accepts Modernized S-61TM Helicopters for Use in Afghanistan
^ Aircraft Accident Report. Los Angeles Airways, Inc. S-61L Helicopter, N300Y, Compton, California, Adopted: August 27, 1969
^ UPI. Helicopter Crash Kills Five. Beaver County (Pa.) Times: Tuesday, 17 May 1977, A-13.
^ Schneider, Daniel B. "F.Y.I.", July 25, 1999. Accessed September 30, 2007. "Q. Back in the 1960's and 70's, helicopters bound for Kennedy International Airport used to take off from a deck atop the old Pan Am Building. Why was the service halted? A. As many as 360 helicopter flights a day were planned by New York Airways after the 59-story Pan Am building was completed in 1963, but a bitter public outcry delayed the first few flights until Dec. 21, 1965.... The operation proved unprofitable, however, since the helicopters carried an average of only eight passengers, and the heliport, which had cost $1 million to build, closed in 1968.... After another round of hearings -- and renewed protests -- flights resumed in February 1977. Three months later, the landing gear on one of the Sikorsky S-61 helicopters collapsed while passengers were boarding, flipping it on its side and sending a 20-foot rotor blade skidding across the roof and over the west parapet wall.... Within hours, the heliport was closed indefinitely."
^ "USFA Fatality Notice". United States Fire Administration. 2008-08-06. Retrieved 2008-08-11.
^ "FAA/NTSB Investigations". Los Angeles Injury Law Firm (See post #4 titled "Nine Firefighters Believed Dead After Helicopter Crash in California"). 2008-08-06. Retrieved 2009-02-03.

External links

[Frawley_Civil_43-1] ^ ^a ^b ^c ^d ^e ^f ^g ^h Frawley, Gerard: The International Directory of Civil Aircraft, 2003-2004, p. 194. Aerospace Publications Pty Ltd, 2003. ISBN 1-875671-58-7.

[Apostolo-2] Apostolo, G. "Sikorsky S-61".The Illustrated Encyclopedia of Helicopters. Bonanza Books, 1984. ISBN 0-517-439352.

[3] "The Self-Supporting Helicopter" Time Magazine December 26, 1960

[CarsonAbout-4] Carson Helicopters (2009). "About Carson Helicopters". Retrieved 2009-01-12.

[5] Press Releases: U.S. State Department Accepts Modernized S-61TM Helicopters for Use in Afghanistan

[ussd_s61t-6] Sikorsky S-61T gains new life in State Department program

[7] S-61 in FAA

[utcs61eis-8] Press Releases - U.S. State Department Accepts Modernized S-61TM Helicopters for Use in Afghanistan

[Report-9] Aircraft Accident Report. Los Angeles Airways, Inc. S-61L Helicopter, N300Y, Compton, California, Adopted: August 27, 1969

[19770517+Beaver+Helicopter-10] UPI. Helicopter Crash Kills Five. Beaver County (Pa.) Times: Tuesday, 17 May 1977, A-13.

[11] Schneider, Daniel B. "F.Y.I.", July 25, 1999. Accessed September 30, 2007. "Q. Back in the 1960's and 70's, helicopters bound for Kennedy International Airport used to take off from a deck atop the old Pan Am Building. Why was the service halted? A. As many as 360 helicopter flights a day were planned by New York Airways after the 59-story Pan Am building was completed in 1963, but a bitter public outcry delayed the first few flights until Dec. 21, 1965.... The operation proved unprofitable, however, since the helicopters carried an average of only eight passengers, and the heliport, which had cost $1 million to build, closed in 1968.... After another round of hearings -- and renewed protests -- flights resumed in February 1977. Three months later, the landing gear on one of the Sikorsky S-61 helicopters collapsed while passengers were boarding, flipping it on its side and sending a 20-foot rotor blade skidding across the roof and over the west parapet wall.... Within hours, the heliport was closed indefinitely."

[12] "USFA Fatality Notice". United States Fire Administration. 2008-08-06. Retrieved 2008-08-11.

[13] "FAA/NTSB Investigations". Los Angeles Injury Law Firm (See post #4 titled "Nine Firefighters Believed Dead After Helicopter Crash in California"). 2008-08-06. Retrieved 2009-02-03.

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v t e Sikorsky aircraft
Fixed-wing aircraft (company designations)	S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 S-12 S-13 S-14 S-15 S-16 S-17 S-18 S-19 S-20 S-21 S-22/23/24/25/26/27 S-28 S-29-A S-30 S-31 S-32 S-33 S-34 S-35 S-36 S-37 S-38 S-39 S-40 S-41 S-42 S-43 VS-44 S-45
Fixed-wing aircraft (military designations)	C-6 C-28 JRS JR2S PS P2S RS XBLR-3 XPBS XSS XV-2
Helicopters (company designations)	VS-300 (S-46) S-47 S-48 S-49 S-50 S-51 S-52 S-53 S-54 S-55 S-56 S-57 S-58 S-59 S-60 S-61 S-61L/N S-61R S-62 S-63 S-64 S-65 S-66 S-67 S-68 S-69 S-70 S-71 S-72 S-73 S-74 S-75 S-76 S-80 S-92 S-95 S-97 S-100 S-102 S-103 S-300 S-333 S-434
Helicopters (military designations)	SH-3 Sea King HH-3E/F R-4 H-5 H-6 H-18 H-19 Chickasaw H-34 Choctaw CH-37 Mojave XH-39 HH-52A Seaguard CH-53 Sea Stallion CH-53E Super Stallion CH-53K King Stallion MH-53 CH-54 Tarhe UH-60 Black Hawk HH-60G Pave Hawk HH-60J/MH-60T MH-60R/S Seahawk SH-60B/F Seahawk H-60J/K VH-60 RAH-66 Comanche VH-92 Patriot CH-124 Sea King CH-148 Cyclone HLH
Experimental aircraft	Cypher/Cypher II Firefly Raider Raider X SB-1 X2 XBLR-3 XV-2

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