The angled blades you see on the front of many helicopters are not radio antennas or hood ornaments as many might believe. They are the components that make up the Wire Strike Protection System (WSPS). Developed between 1977-1979 – in response to a request from the Canadian Forces – Bristol Aerospace in Winnipeg invented this simple system to protect helicopters from the often fatal results of a wire strike in low-level flight. Using this lightweight – under 10 kg – system, helicopters are able to vastly increase their chances of surviving a wire strike. The WSPS can cut multiple cables and provides up to a 95% chance of flying away from an encounter with a wire.


The WSPS was developed by a mixed team of personnel from Bristol Aerospace that included one of the Museum’s founding members Doug Emberly and members of the Canadian Forces. Tests were done in Winnipeg and Gimli using several different set-ups, including some 48 runs at different speeds and with different wires using a truck-mounted CH 136 helicopter fuselage.

Further tests were conducted at the Langley Research Center’s Crash Impact Dynamics Research Facility in Hampton, Virginia.  Flight was simulated by using an OH-58 Kiowa as the weight of a 200-foot giant pendulum that swung the helicopter into sets of suspended wires.


The WSPS received DOT and FAA certification by 1980 and has since been adapted to most helicopter types. It is still being manufactured and is in use on helicopters around the world today.

Nelson Chan, the engineer at Bristol who designed the WSPS, was selected as the 1980 recipient of the Romeo Vachon award. This award is presented annually to recognize an outstanding display of initiative, ingenuity and practical skills, in the Art, Science and Engineering of Aeronautics and Space in Canada.