Helicopter Sikorsky H-19B Chickasaw Serial 55-544 Register 52-7594 used by US Air Force USAF. Built 1953. Aircraft history and location Aircraft History 52-7594 US Air Force 1953-10-23Sikorsky S-55 c/n 55-544, ff:? del USAF as H-19B, 52-7594, 23Oct53. Send Updates Use APP to upload photo @ (optional) When Now? / / Send