Helicopter Sikorsky H-19B Chickasaw Serial 55-489 Register 51-3968 used by US Air Force USAF. Built 1953. Aircraft history and location Aircraft History 51-3968 US Air Force 1953-07-27Sikorsky S-55 c/n 55-489, ff:? del USAF as H-19B, 51-3968, 27Jul53. Send Updates Use APP to upload photo @ (optional) When Now? / / Send