Helicopter Sikorsky HO4S-3 Serial 55-631 Register 138580 used by US Navy USN. Built 1954. Aircraft history and location Aircraft History 138580 US Navy 1954-01-05Sikorsky S-55 c/n 55-631, ff:? del USN as HO4S-3, 138580, 05Jan54. 1957-07-12 A NZPG Accident crashed with VX-6, while returning to McMurdo Sound, just short of the base. VXE-6 Send Updates Use APP to upload photo @ (optional) When Now? / / Send