Beartrap (hauldown device)

A helicopter hauldown and rapid securing device (HHRSD) or beartrap enables helicopters to land on and depart from smaller ships in a wide range of weather conditions. Similar devices are referred to as RAST and TRIGON.

The beartrap was developed in response to the difficulties encountered when attempting to land larger helicopters on smaller ships. Until the hazard was effectively addressed, it was impractical to conduct such operations, thus multiple navies looked into various methods of easing ship-based landings under adverse conditions. During the late 1950s, the Royal Canadian Navy refitted the frigate HMCS Buckingham with an experimental flight deck with the prototype beartrap; it underwent successful testing with Sikorsky HO4S-3 and Sikorsky H-34 helicopters. A second series of trials onboard HMCS Assiniboine (DDH 234) during the early to mid-1960s led to the beartrap being cleared for operational use with the Royal Canadian Navy during April 1967. The Sikorsky CH-124 Sea King was the first Canadian helicopter to operationally use this landing system.

Other navies promptly introduced this technology, or similar counterparts. The Royal Navy and the United States Navy were early adopters after the Royal Canadian Navy's positive experience. The system is not only used by helicopters, but also for the retrieval of unmanned aerial vehicles (UAVs). It continues to be routinely used, largely unchanged since its original development, into the twenty-first century.