The Hiller 1100 prototype, N81005 (c/n 1) first flew on on 21 January 1963. The type competed in the US Army's Light Observation Helicopter (LOH) competition and 62-4206 was the first YOH-5A. Although the serial is correct, it was found at some point that 62-4201 had been assigned twice, to a C-140 and a Bell YOH-4, and thus a few serials were changed, 4206 becoming 4207 in a paper exercise. This airframe was also NASA 530. Photo from: Wright State University