Detailed history and photos of helicopter Sikorsky HO4S-3 Serial 55-580 Register 138515 used by US Navy USN Track service timeline and current status. Aircraft History 138515 US Navy 1953-11-10Sikorsky S-55 c/n 55-580, ff:? del USN as HO4S-3, 138515, 10Nov53. Send Updates Use APP to upload photo @ (optional) When Now? / / Send
