Helicopter Sikorsky HR2S-1 Serial 56-115 Register 145873 used by US Marine Corps USMC. Built 1959. Aircraft history and location Aircraft History 145873 US Marine Corps 1959-03-25Sikorsky S-56, c/n 56-115, ff:? del USMC as HR2S-1, 145873, 25Mar59 xfer HMH-461, unk wfu & std MASDC, unk noted National Metals scrapyard, Tuscon, AZ as N73992, 06Jul01. HMH-461 1968-04-30soc 30apr68 Send Updates Use APP to upload photo @ (optional) When Now? / / Send