Helicopter Sikorsky HO4S-3 Serial 55-554 Register 138507 used by US Navy USN. Built 1953. Aircraft history and location Aircraft History 138507 22Oct53 US Navy 1953-10-22Sikorsky S-55 c/n 55-554, ff:? del USN as HO4S-3, 138507, 22Oct53. 1955 A Ellsworth Stationwith VX-6 at Ellsworth Station until c 1958 VXE-6 Send Updates Use APP to upload photo @ (optional) When Now? / / Send