Helicopter Sikorsky H-19B Chickasaw Serial 55-439 Register 51-3945 used by US Air Force USAF. Built 1953. Aircraft history and location Aircraft History 51-3945 US Air Force 1953-06-11Sikorsky S-55 c/n 55-439, ff:? del USAF as H-19B, 51-3945, 11Jun53. Send Updates Use APP to upload photo @ (optional) When Now? / / Send