Helicopter Sikorsky H-37A Mojave Serial 56-121 Register 57-1656 used by US Army Aviation Army. Built 1959. Aircraft history and location Aircraft History 57-1656 US Army Aviation 1959-06-23Sikorsky S-56, c/n 56-121, ff:? del US ARMY as H-37A, 57-1656, 23Jun59 redesig CH-37A, Oct 62 conv CH-37B, unk wfu & soc unk. scr 1970 Send Updates Use APP to upload photo @ (optional) When Now? / / Send