Detailed history and photos of helicopter Sikorsky HO4S-3 Serial 55-632 Register 138581 used by US Navy USN Track service timeline and current status. Aircraft History 138581 US Navy 1954-01-05Sikorsky S-55 c/n 55-632, ff:? del USN as HO4S-3, 138581, 05Jan54. Send Updates Use APP to upload photo @ (optional) When Now? / / Send
