Detailed history and photos of helicopter Sikorsky HO4S-3 Serial 55-706 Register 138597 used by US Navy USN Track service timeline and current status. Aircraft History 138597 US Navy 1954-05-10Sikorsky S-55 c/n 55-706, ff:? del USN as HO4S-3, 138597, 10May54. Send Updates Use APP to upload photo @ (optional) When Now? / / Send
