Detailed history and photos of helicopter Sikorsky HO4S-3 Serial 55-604 Register 138519 used by US Navy USN Track service timeline and current status. Aircraft History 138519 US Navy 1953-11-30Sikorsky S-55 c/n 55-604, ff:? del USN as HO4S-3, 138519, 30Nov53. Send Updates Use APP to upload photo @ (optional) When Now? / / Send
