The year was 1972. The year when the USAF had learn their lessons in the Vietnam War. This year gave the need to replace Bell’s Huey series and produce more reliable and versatile helicopter. And so, the US Army commissioned the Sikorsky and Boeing-Vertol to produce and initially test 3 prototypes helicopters that were robust, simple, and within the requirements of the UTTAS or the Utility Tactical Transport Aircraft System.