Helicopter Sikorsky H-37A Mojave Serial 56-037 Register 55-612 used by US Army Aviation Army. Built 1957. Aircraft history and location Aircraft History 55-612 US Army Aviation 1957-08-06Sikorsky S-56, c/n 56-037, ff:? del US ARMY as H-37A, 55-612, 06Aug57 redesig CH-37A, Oct 62 conv CH-37B, unk wfu & soc unk. Send Updates Use APP to upload photo @ (optional) When Now? / / Send