In December 1957, the US Navy began a new program to develop a high performance helicopter to replace the outdated S-58 (HSS-1). Sikorsky Aircraft proposed a large twin turbine helicopter with a boat-type hull and retractable landing gear for amphibious operations. The S-61 aircraft, first designated as HSS-1, then HSS-2, made its first public factory flight on March 11, 1959. The US Navy ordered the first ten S-61B/HSS-2 for delivery starting in September 1961. One year later, the HSS-2 was redesignated to SH-3A (H-3A, D, G, H). The H-3 helicopter was the first helicopter to incorporate an automatic blade fold system. It was also the first helicopter to fly faster than 160 mph (257 kph).

In 1960, the Royal Canadian Navy decided to procure the HSS-2 helicopter for use in the ASW hunter-killer role and flying off the flight decks of destroyers. Operating such a large aircraft from a very small flight deck resulted in the development of the "Beartrap", a helicopter hauldown device which is explained in detailed in an accompanying document. Flight operations are possible without the Beartrap but the Beartrap allows flight operations in higher sea states.

Initially designated the CHSS-2, it was August 1st 1963 when the first Sea King helicopters landed at Shearwater N.S. and taken on strength. The first four of  forty-one CHSS-2s were identical to the USN SH-3A and Assembled by Sikorsky while the remainder were assembled from kits in Longeuil, Quebec by United Aircraft of Canada. These incorporated minor changes including flotation bags on the sponsons and FOD (Foreign Object Damage) deflectors. All machines were delivered by 1969 to HS-50 and HU 21 squadrons of the Royal Canadian Navy, who in turn, provided detachments to ships as required.

The Sea Kings all entered service with the designation CHSS-2 and serial numbers from 4001 to 4041. For the survivors, the designation changed to CH-124 effective 27 July 1970 and the serials to the 12401 to 12441 range effective 14 August 1970. Those that were still in service underwent SKIP (Sea King Improvement Programme) in 1975/76 and were redesignated as CH-124A.

Decked out in the traditional Royal Canadian Navy colors, with their bright orange noses and vintage roundels, aircraft 401, 402 and 403 began what is now over 46 years of integral helicopter support to naval operations. After the Canadian Armed Forces integrated in 1968, the Sea King designator changed to that of CH-124.

Taken at Halifax , N.S on September 9, 2006. (Canadian Forces photo #SW2006-0343-66 by Private Amy Martin)

Crew: Two  pilots, a Tactical Coordinator (TACCO), and an Airborne Electronic Sensor Operator (AESOP)
Quantity ordered : 41
Quantity on strength as of 2007: 27
Taken on strength: Between 1963 and 1969
Capacity: Up to 3 passengers
Length: 54 ft 9 in (16.7 m)
Rotor diameter: 62 ft (19 m)
Height: 16 ft 10 in (5.13 m)
Empty weight:11,500 lb (5,216 kg) [1]
                     11,865 lb (5,382 kg) [2]
Loaded weight: 19,100 lb (8,664 kg) [1]
                        18,626 lb (8,449 kg) [2]
Max takeoff weight: 22,050 lb (10,000 kg)
Original Powerplant: 2 × General Electric T58-GE-8 turboshafts, 1250 shp. Later upgraded to T58-GE-8F-100 standards which produced 1500 shp. These 1500 shp powerplants are the most powerful which are available for the Sea Kings.
Fuel type: F-44 (JP-5)
Fuel capacity: Two tanks whose total capacity is 583 Imp gal.
Oil capacity: Two tanks. One for each engine. Each tank has a capacity of 2.25 Imp. gal.

Maximum speed: 166 mph (267 km/h) [2]
Range: 621 mi (1,000 km) [2]
Service ceiling: 14,700 ft (4,481 m)  [2]
Rate of climb: 1,310-2,220 ft/min (400-670 m/min) [2]

Original Armament:

With four external weapons carriers mounted, each can carry: a Mk 43 torpedo, MK 44 torpedo, or a Mk 54 depth bomb. The starboard forward carrier was modified to enable the fitting of a MK 101 depth bomb.

Ian Snow provides some details about the double bomb carrier originally fitted to the Sea King. " I do remember this device although it wasn't used for carrying bombs.  It mounted on the port-rear weapon station and was used for the carriage of parachute flares or more likely sonobouys (ASW stores) back when HMCS Bonaventure was still in service.    It carried four stores, two side by each forward, two aft.  Each had it's release mechanisms, the same solenoid used for the release of a torpedo or depth charge.  The pilot(s) could sequentially release the stores using the normal weapon release mechanism in the cockpit.  I've seen it installed on a Sea King at Shearwater but never on a Detachment bird.  When I flew with it we had paraflares for night overeater SAAR sorties.

The rack would have been a casualty of the Sea King upgrade when internal sonobuoy launch tubes and internal storage were added".

Current Armament:

* Two x  Mk 46 Mod V anti-submarine homing torpedoes.
* Various sonobuoys and pyrotechnic devices.
* Self defence machine gun (only fitted in some variants).

Additional (current) sensors:

* Forward Looking Infrared (FLIR), Passive Active Sonar, Surface Search radar. In order to locate submarines, the Sea King's sonar lowers a transducer into the water mounted at the end of a 450 foot cable. The Sea King can also be fitted with FLIR (Forward Looking Infra-Red) to find surfaced submarines in the dark of night.

seaking_dimensions_s.jpg Sea King dimensions diagram. Click to enlarge. From  RCN Aircraft General Information Data . Dated May 1, 1963. (Provided by Leo Pettipas) 


CH-124  - This was the original helicopter ordered for the RCN. Out of the forty-one aircraft, four were assembled were assembled by Sikorsky and thirty-seven by United Aircraft of Canada.  A “Gulf  Mods” defensive aids package was mounted on six CH-124 airframes. Most of the work focused on prolonging airframe life, replacing some of the avionics which were no longer logistically supportable.

CH-124A - After a decade of service, the sub-hunting electronics and radar of Canadian Sea Kings were obsolescent. In 1972, the Sea King Improvement Program (SKIP) began. The CH-124A (as SKIP Sea Kings were redesignated) had a new surveillance radar (Litton AN/APS-503) with a distinctive fuselage-top radome and largely modernized avionics as well as improved safety features.  Improvements were made to the dipping sonar and sonobuoy chutes added in the late ’70s. This mid-life rebuild, performed by United Aircraft of Canada, brought CH-124As up to then-current standards for Sea Kings in other navies.

CH-124B -  In the mid-’80s, six CH-124As were converted into ‘Bravos’. 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. A Vertical Insertion Search and Inspection Team (VISIT) capability was practised ,but , plans to install EAPSNIPS (Engine Air Particle Separator / Snow & Ice Particle Separator) did not come to fruition.  The CH-124Bs differed in ASW kit. Whereas ‘Alphas’ used active sonar (dipping or active sonobuoys), the ‘Bravos’ employed passive sonobuoy processing.

CH-124B2 -  Six CH-124B's were upgraded to the CH-124B2 standard in 1991-1992. The revised CH-124B2 retained the sonobuoy processing gear to passively detect submarines.  The passive sonobuoy capability was used to localize submarine contacts detected by the ships’ passive Towed Array Sonar (TAS). Since anti-submarine warfare is no longer a major priority within the Canadian Forces, the CH-124B2s were refitted again to become improvised troop carriers for the newly formed Standing Contingency Task Force. The SCTF is a high-readiness special operations force meant to be ready to deploy within 10 days notice.

CH-124C -  One CH-124C is operated by the Helicopter Operational Test and Evaluation Facility (HOTEF) located at CFB Shearwater. It is used for testing new gear, and when not testing new gear, it is deployable to any Canadian Forces ship requiring a helicopter. This helicopter is rotated periodically with other helicopters in the fleet.

CH-124U -  Unofficial designation for four CH-124's that were modified for passenger/ freight transport by the IMP Group, Halifax. One crashed in 1973. The surviving aircraft were later refitted to become CH-124A's. One of them is the single "water bird".  It has all non-essential avionics removed and non-critical holes permanently covered over with plates.  It is used for training the pilots in ditching and single-engine water take-off techniques in MacDonald's Lake.  This lake is located on the east side of the main Shearwater runway.  The water bird can be easily identified in photos as a result of  yellow tape which has been applied to seal the access bay panels and the passenger door seals.  The water bird is actually a different aircraft for each water bird training season. Canadian Sea King pilots undergo one hour of waterbird training yearly. All that training has been instrumental in the successful ditching and in some cases subsequent recovery, of several helicopters at sea.  All of these "U" variants could be reconfigured to ASW status in fairly short order.



Initially the Sea King was  permitted to fly into icing conditions, however this was determined to be problematic at a later time. One major problem which was addressed with the CH-124A modifications was that of icing. Ian Snow recalls those issues.   "In early pictures  of the Sea King (mostly USN), you clearly see the front intakes of the two engines.  There was a problem with ice being ingested into the engine and destroying it.  The "FOD Mod", a Canadian development adopted by all military operators of the Sea King, was a fiberglass moulding that sits on atop the cabin over the pilots and in front of the engines.  It has a sloped face and flat top.  There is a vertical bulkhead running fore and aft between the engines, so air is taken in from the side versus the front.  The FOD mod resulted in about a 5% loss of engine efficiency but that was balanced against the icing risk.  It also has an integral electric heater to prevent ice accumulation.

The CH-124A programme included an attempt to add electrical de-icing on both the main and tail rotor blades.  It was a good idea but the de-icing boots were bonded to the leading edge of the rotors.  At the hub end, the electrical cable left the boot at a 90 degree angle to the spar and after approximately 1.5 inches made a 90 degree bend towards the blade attachment bolts.  After about 6 inches,  there was a fitting with a Canon plug where the boot was connected to the aircraft wiring.

The first problems arose with the tail rotor blades.  Essentially, the centrifugal forces were such that the bond between the blade and the base of the electrical cable would pull away and begin progressing down the blade spar.  We (HMCS Huron Detachment) discovered this while in the Puerto Rico operational areas and messaged the situation back to Shearwater, with a recommendation to revert our two "at-sea trials version" CH-124A's back to the original tail rotor system while the situation was investigated further.  I was astonished to receive a message back in very short order to the effect that the problem had already been noted at home base, in a test flight by a CH-124A . Two complete rotor systems would be shipped later the same day.  This was very indicative of the very proactive support system we enjoyed at Shearwater.  As I recall the "fix" was to redesign the plug bracket to relieve the back-pressure on the electrical pigtail.

As I recall the problem with the main rotor blade system manifested itself later.  It wasn't the delaminating problem experienced with the tail rotor but the control unit 'frying' itself.  When selected to "On" and when temperature dropped to the appropriate setting, the control unit would begin "pulsing" current directly from the AC generators to the blades.  A very crude way to do the job but I suppose in a civilian helicopter probably very effective.  In a military helicopter, stuffed full of a lot of electronic sensors, it could have some mysterious effects.  I don't know what the ultimate 'fix' was for this problem bit it was still an open issue when I left the scene in 1986.

For the aircrew, the bottom line was that even if the system working as intended it still would not have allowed us to fly into forecasted icing conditions (e.g. freezing level on the ground over the hills between Shearwater and Greenwood NS so we really didn't see the value of spending that kind of money on a lot of dead weight that shortened our endurance."

David Wall, a Sea King pilot from the mid-1960s era, remembers one trip in particular.  " I had an interesting trip one evening returning from Ontario (with ice deflector installed) when we picked up a load of ice crossing the Bay of Fundy. There were no control problems, since we rattled the cyclic around every few minutes to shake it off but with Shearwater weather very poor we diverted into Greenwood and when we engaged the rotor brake after shutdown, we were suddenly the centre of a 62 foot diameter of ice cubes that came fell over us when we stepped out of the helicopter".


Between 1998 and 2002, Canadian Forces Sea Kings had their 1250 shp T58-GE-8F turboshafts upgraded to T58-GE-100 standards. These 1500 shp powerplant are the most powerful available for Sea Kings.


By 1998, each of the operational helicopters had accumulated between 10,000 and 12,000 hours of flight time and also showing serious signs of wear. At the time each aircraft required 25.2 hours of maintenance for every hour of flight time.

Fatigue cracking in load bearing frames at Flight Stations 243.5 and 290, caused largely by the extended life of the aircraft and operational loads, necessitated a comprehensive solution if the helicopters had to remain operational until 2005. This was addressed by the Centre Section Repair (CSR) program. By the spring of 1998, eight aircraft had their centre sections replaced at a cost of $500,00 per helicopter. Another eleven refits were also authorized at that time.

The centre section replacement was incorporated into the Depot Level Inspection and Repair (DLI) program which was performed by IMP Aerospace, Halifax at the rate of four aircraft per year, Each Sea King undergoing the DUR required approximately 7,500 person hours of work and a 120 working day turnaround time. The centre section work increased the turnaround time to 145 days.

Over a seven month period, four Sea Kings had problems with their tail wheel struts. Two of them broke upon landing, and cracks were found in two others. A reinforced tail wheel strut program was then proposed to address the problem..


By 1998 , the helicopter's inverters and the transformer rectifier units were replaced in order to improve the quality of the available power  The power supplied by the original electrical system was not pure enough to power digital equipment.


It is known that IMP Aerospace (at least up to the 1980's) did some of the major periodic inspections . Each one took 66 days to complete.  These inspections were done both at their own hangar and in the main hanger at Shearwater, with IMP crews working alongside with Canadian Forces crews, each with their own aircraft.

Original paint scheme from the mid 1960's: When the Sea King entered RCN service, deliveries were in the standard Dark Grey/Light Grey RCN finish, with current RCN roundels.  All were embellished with large areas of high visibility markings painted (Red Day-Glo) to the lower nose, a fuselage tail band (not completed on bottom) and horizontal tail stabilizer.  With Unification, the Sea King fleet was to receive an overall Grey 501-109 with full colour CAF Era markings, changing to Symmetrical Era markings around 1973. (From the collection of David Wall)

In the "old days" Sea King Detachments would paint the assigned ship's crest on the "FOD MOD".  In 1972, the practice was banned by 'higher authority' but today the practice has been restored.   It is a significant statement of ship/air team spirit.

Latest paint scheme: In the 1980's, the FIP (Government of Canada's corporate identity program) arrived with the Sea King adopting the overall darker Grey 26173 and the even darker Grey 26118 markings. Here, Sea King 430 is seen at  Port au Prince International Airport, Haiti on January 20, 2010. (DND photo DA2010-0004-02 taken by Master Corporal David Hardwick)

As of June 2010, all the Sea Kings remain operational but operations will start to be phased out in 2012 as the CH-148 Cyclone helicopters are taken on strength.  Aircrew and technicians will be trained on the Sea King as long as they can gain six months of experience working with the CH-124 before entering conversion training for the CH-148.

Major Wayne Joy, Staff Officer for the maritime helicopter project at 12 Wing Shearwater, is responsible for all activities related to the transition from the CH-124 Sea King to the soon-to-arrive CH-148 Cyclone. He says:

“We’re introducing night-vision goggles in the Sea King because, with the new aircraft, that’ll be part of our day-to-day operations, and operating with NVGs is significantly different from flying unaided,” Maj Joy explains. Flying with night-vision goggles means no depth perception, little to no peripheral vision and a lack of contrast in the image presented due to the green wash imposed by the goggles".
Another significant difference that Maj Joy and his team hope to prepare Sea King crews for is the overabundance of information that will be available on the Cyclone. Whereas the tactical crew on a Sea King must continually input information on contacts they are tracking, the numerous software systems in the Cyclone will enable it to track many contacts independently. This will allow the crew to take a more strategic role in analyzing the data rather than constantly updating it.

Much has been written about the very lengthy Sea King replacement program.  For any readers who wish to review  the issues surrounding this procurement, please  refer to the excellent white paper on the topic written by Aaron P. Plamondon in 2002.

There are 25 Sea King helicopters in the military's fleet as of July 2013, two of which are kept grounded to train maintenance crews. Another two are on overseas missions. DND is still awaiting delivery of the replacement CH-148 Cyclone helicopters at this time.

by Jonathan Muma and The Canadian Press
It’s a milestone many people probably never thought they’d see, or wanted to see, for that matter. The Sea King helicopter turns 50 today (Aug 1/13) . The first two Sea Kings arrived at CFB Shearwater on Aug. 1, 1963, and were expected to serve mainly as Cold War submarine hunters. But since then, the choppers have had to adapt to a variety of missions such as providing supplies to troops in Somalia and monitoring surface vessels during the First Gulf War.

Even as we celebrate the anniversary, however, the well-documented problems with the helicopters continue to be compounded by the fact we still don’t know when they’ll be replaced. As recently as this month (July 2013) , the entire fleet was grounded for four days when a Sea King tipped over while landing at CFB Shearwater, smashing its rotor blades on the tarmac.The fact the helicopters are still operational is a testament to the men and women who keep them in air, but it also shows the shortcomings of government after government who have been unable to replace the often troubled Sea Kings.

In February, defence policy expert at the University of British Columbia Dr. Michael Byers blasted the government and its deal with Sikorsky, which was supposed to start sending replacement Cyclones helicopters in 2008. He noted then that company should be facing serious penalties.  “But the government of Canada finds itself reluctant to impose any penalties because a significant cause for the delay were the actions of the Department of National Defence in requesting new equipment,” he said. Dr. Byers added even the Department’s minister admitted serious problems. “The worst procurement in the history of Canada, to quote Defence minister Peter MacKay,” he said.

From fighter jets to helicopters, it’s a situation Canada seems to keep finding itself in.

“The answer to the problem is much more stringent oversight by elected politicians over the Department of National Defence, not just at the initial approval stage, but at every stage of the procurement moving forward,” explained Dr. Byers. With no date set for the arrival of the first fully capable Cyclone, or the retirement of the last Sea King for that matter, it has many wondering how many more anniversary celebrations are ahead. None the less, 50 years is a big deal and there will be some public events in Halifax to celebrate the milestone.

Ten bells were rung today in Halifax to formally remember the Canadian air crew members who died operating Sea King helicopters over the past 50 years.

The commemoration service in the city’s Grand Parade recognized the Sikorsky helicopter’s golden anniversary in the Canadian military and included a flyover of the choppers from nearby Canadian Forces Base Shearwater.

Mark Mander, chief of the Kentville, N.S., police force, accepted a Memorial Ribbon, a decoration given to the families of people who die while serving in the Canadian Forces.


423 Maritime Helicopter Squadron conducted its final operational flight of  the CH-124A Sea King helicopter on January 26, 2018 with a flypast over Halifax Harbour and Shearwater, Nova Scotia.

423 Squadron personnel will now turn their full attention to transitioning to the CH-148 Cyclone, the Royal Canadian Air Force’s new maritime helicopter.

It’s not the last time that residents of the Halifax and Dartmouth area will see the venerable Sea King in flight, however. 443 Maritime Helicopter Squadron, located at Patricia Bay, British Columbia, will support Royal Canadian Navy operations on both coasts until the Sea King is formally retired at Patricia Bay at the end of this year. Both 443 and 423 Squadrons are part of 12 Wing Shearwater.

The Sea King has been in service with the Royal Canadian Navy and Royal Canadian Air Force for 54 years. The first Cyclone detachments onboard Navy ships are planned for mid-2018.

As of October 5/18,  the Sea King  helicopters are up for sale. Here is their status: Twenty three Sea Kings have been retired from flying status, and five are still being operated by 443 Squadron in Patricia Bay, BC.

Eight aircraft are being retained by DND/CAF for display at publicly accessible bases and museums. One aircraft is being retained by DND/CAF as a training aid and one aircraft is being transferred to the Canada Aviation and Space Museum in Ottawa for public display

After 55 years of serrvice, the Sea King will officially be retired by December 31, 2018 as the RCAF completes its transition to the new CH-148 Cyclone maritime helicopter. The CH-124 Sea King fleet has flown more than 550,000 hours, which, at a cruising speed of 162 km/h, is roughly equivalent to flying 7,200 times around the Earth,  Over its long history, the CH-124 Sea King participated in a wide variety of operations, including NATO and other international maritime operations; search and rescue; disaster relief; counter-narcotic operations; international peacekeeping; counter-piracy; and pollution and fisheries patrols.

Electronics Suite
Operational Information
Vintage Photos
T-58 Engine and Control Panels
The Beartrap
Other and Current Photos
You Tube Video Clip - A Ride in A Sea King
You Tube Video Clip - 50th Anniversary of the Sea King
You Tube Video Clip - Another 50th Anniversary tribute

[1] With original fitting of 1,250 shp engines.
[2] When fitted with 1,500 shp engines.

Credits and References:

1) Ian Snow <va3qt-4(at)>
2)  Ernest Cable <erncar(at)> Associate Air Force Historian and Shearwater Aviation Museum Historian .
3) 423 Squadron
6) HSS-2 backgrounder
7) David Wall <walld(at)>
9) Leo Pettipas <lpettip(at)>  Associate Air Force Historian. Air Force Heritage and History 1 Canadian Air Division.
Winnipeg, Manitoba.
10) Variants
11) Variants
12) Evergreen  Sea King by Sharon Dobson

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Feb 23/21