Helicopter Sikorsky H-19B Chickasaw Serial 55-760 Register 53-4421 used by US Air Force USAF. Built 1954. Aircraft history and location Aircraft History 53-4421 US Air Force 1954-09-02Sikorsky S-55 c/n 55-760, ff:? del USAF as H-19B, 53-4421, 02Sep54. Send Updates Use APP to upload photo @ (optional) When Now? / / Send