Helicopter Sikorsky H-19A Chickasaw Serial 55-173 Register 51-3894 used by US Air Force USAF. Built 1952. Aircraft history and location Aircraft History 51-3894 US Air Force 1952-07-03Sikorsky S-55 c/n 55-173, ff:? del USAF as H-19A, 51-3894, 03Jul52. Send Updates Use APP to upload photo @ (optional) When Now? / / Send