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Background  —  CF Naval Helicopter  —  CH-124 Sea King  Variants

This page is provided as background for the  Maritime Helicopter Project  and  the oft-rumoured deploying of  Sea Kings to Afghanistan.

Canada’s Sea Kings first entered service in 1963 as the Royal Canadian Navy’s CHSS-2 (right). Airframe components were made by Sikorsky in Connecticut but most Canadian Sea Kings were assembled in Montreal by United Aircraft. (The Sea King was not the Navy’s first choice – the RCN would have preferred smaller helicopters. But US Navy Sea Kings had shown  the type’s suitability to anti-submarine warfare missions as well as its reliability. The Helicopter Haul-down Rapid Securing Device or ‘Beartrap’ tailored the Sea King to Canadian destroyer decks. Upon unification of  Canada’s Forces, the CHSS-2 was re-designated CH-124.

“Old boots were once new ...” – SKIP CH-124A Upgrades
After a decade of service, the sub-hunting electronics and radar of Canadian Sea Kings was obsolescent. In 1972 the Sea King Improvement Program began. The CH-124A (as SKIP Sea Kings were redesignated) had a new surveillance radar (Litton APS-503) in a distinctive fuselage-top radome and largely modernized avionics as well as improved safety features.  Improvements to the dipping sonar [1] were done and sono- buoy chutes added in the late ’70s. This mid-life rebuild (done by original Sea King assemblers, United Aircraft of Canada) brought CH-124As up to then-current standards for Sea Kings in other navies.

Tweaking the Sea Kings – “Gulf Mods”
There have been two attempts to replace CF Sea Kings. The New Shipboard Heli- copter ( EH-101 ) was to be in service by 1995 but Canada found itself involved in the Persian Gulf  in 1990. The Sea Kings lacked  night-vision and  defensive aids. A “Gulf  Mods” defensive aids package was mounted on eight CH-124 airframes.

Passive Agressive Tendencies – the ‘Bravo’
‘Gulf  Mods’ could be applied to two models of Sea King for, in the mid-’80s, 7 CH-124As were converted into ‘Bravos’. The CH-124Bs differed in ASW kit. Whereas ‘Alphas’ used active sonar (dip or sonobuoy), the ‘Bravos’ employed passive listening. The CF planned to replace these aircraft with CH-148 Petrels with towed sonar arrays. The next Sea King sub-model could be seen as a lead-in trainer.

HELTAS  –  the  HELicopter Towed-Array Support
In 1991-92 six Bravos were upgraded as CH-124B-2s. The revised ’B-2 retained the sonobuoy processing gear to passively detect submarines but, the aircraft was now also fitted with a towed-array sonar. While HELTAS (applied to both ’B-2 and the towed-array) supplemented ships sonar, other Sea King avionics were obsolete.  ASW is no longer a priority and  the ’B-2 were refitted as ad hoc SCTF [3] troop carriers.

A One-Off  and the Sea King Designation Oddities
One other Sea King sub-type is operated by the CF – the sole CH-124C. Often used as a testbed for the Helicopter Operational Test and Evaluation Facility (HOTEF) at Shearwater NS, when the CH-124C isn’t testing new gear, ‘Charlie’ is deployed aboard  ship like any other Sea King.  Significant changes to CF aircraft do not always result in a new designation – the eight ‘Gulf Mod’ CH-124A/’Bs received none – while at other times unofficial designations are widely used –  such as the ‘CH-124Us’.[4]

Note  for a review of individual CH-124 Sea King variant changes by serial number, see: Bill Walker’s CH-124 Sea King Detailed List page.

[1] The CH-124A uses active sonar – the Bendix AN/AQS-502 ( Canadian AQS-13B ), a dipping transducer ball on a 135 metre-long cable.
[2] Although meant to protect Sea Kings patrolling for unauthorized merchant vessels in 1991, the defensive aids installation wasn’t fully pursued until 2002 other than a handful of E/O turrets shared among the fleet.  For more on the ‘Gulf Mods’, see:  Sea King Troop Carrier.
[3] The Standing Contingency Task Force is a high-readiness special operations force meant to be ready to deploy within 10 days’ notice.
[4] Four CH-124s modified for passenger/freight transport were dubbed CH-124Us. One crashed in 1973, the survivors became CH-124As.

Photo Credits — side views: Stephen Priestley, other images: CF/DND, except bottom left: Texel Airport, and right: © Michael Durning