Detailed history and photos of helicopter Sikorsky HO4S-3 Serial 55-668 Register 138588 used by US Navy USN Track service timeline and current status. Aircraft History 138588 US Navy 1954-03-04Sikorsky S-55 c/n 55-668, ff:? del USN as HO4S-3, 138588, 04Mar54. Send Updates Use APP to upload photo @ (optional) When Now? / / Send
