The Boeing Vertol (formerly Piasecki) H-21A was a single engine, tandem rotor helicopter acquired by the RCAF in 1954 and used primarily for search and rescue work. The Piasecki was also used by the RCAF in transport duties associated with the construction of the various radar chains across Canada.
The H-21 was employed in Comox by 442 Squadron in the SAR role until replaced by the Boeing Vertol Labrador.
The Piasecki at the Comox Air Force Museum