Helicopter Sikorsky HO4S-3 Serial 55-627 Register 138527 used by US Navy USN. Built 1954. Aircraft history and location Aircraft History 138527 US Navy 1954-01-04Sikorsky S-55 c/n 55-627, ff:? del USN as HO4S-3, 138527, 04Jan54. Send Updates Use APP to upload photo @ (optional) When Now? / / Send