Detailed history and photos of helicopter Sikorsky HO4S-3 Serial 55-722 Register 138599 used by US Navy USN Track service timeline and current status. Aircraft History 138599 US Navy 1954-06-02Sikorsky S-55 c/n 55-722, ff:? del USN as HO4S-3, 138599, 02Jun54. Send Updates Use APP to upload photo @ (optional) When Now? / / Send
