Helicopter Sikorsky H-37A Mojave Serial 56-138 Register 58-993 used by US Army Aviation Army. Built 1959. Aircraft history and location Aircraft History 58-993 US Army Aviation 1959-10-10Sikorsky S-56, c/n 56-138, ff:? del US ARMY as H-37A, 58-993, 10Oct59 redesig CH-37A, Oct 62 conv CH-37B, unk wfu & soc unk. Send Updates Use APP to upload photo @ (optional) When Now? / / Send