Helicopter Sikorsky H-19B Chickasaw Serial 55-436 Register 51-3942 used by US Air Force USAF. Built 1953. Aircraft history and location Aircraft History 51-3942 US Air Force 1953-06-12Sikorsky S-55 c/n 55-436, ff:? del USAF as H-19B, 51-3942, 12Jun53. Send Updates Use APP to upload photo @ (optional) When Now? / / Send